Rubber composition for tires

Abstract

[Problem] The purpose of the present invention is to provide a rubber composition for tires which is capable of improving wear resistance, while meeting fashion and design demands. Also, another purpose of the present invention is to provide a rubber composition for tires that offers a wide range of selections when coloring tires and that has excellent durability. [Solution] This rubber composition for tires contains at least a diene rubber, a bio-rubber reinforcing material, and a non-carbon black filler.

Description

Rubber composition for tires

[0001] The present invention relates to a rubber composition for tires with a high biomaterial content, in which diene rubber, non-carbon black filler, and other tire rubber materials are reinforced with a biorubber reinforcement material, and to a tire using the same. Conventional Technology

[0002] In recent years, electric scooters, electrically assisted bicycles, and small electric vehicles have become increasingly popular as means of transportation. Tires for these electric mobility vehicles are often black, with petroleum-derived carbon black used as a rubber filler. However, black tires are not a desirable choice from the perspective of fashion and design. Furthermore, most general tires use petroleum-derived materials, which can contribute to CO₂, a cause of global warming. ２ This is undesirable from an environmental perspective, as it results in large amounts of emissions. Furthermore, tire wear dust generated during driving flows into rivers and into the ocean, eventually turning into microplastics and causing marine pollution.

[0003] Patent Document 1 discloses a tire tread rubber composition for the purpose of providing a tire tread rubber composition that is used in the manufacture of white tire treads that are excellent in abrasion resistance and has an appropriate Mooney viscosity, the tire tread rubber composition being obtained by compounding 10 to 50 parts by mass of titanium oxide, 30 to 90 parts by mass of silica, and 5 to 15 parts by mass of a silane coupling agent relative to 100 parts by mass of diene rubber.

[0004] Patent Document 2 discloses a rubber mixture for colored bicycle tires, which has high abrasion resistance during riding, does not peel off the outer surface of the tire during use, and has a metallic color that is fashionable and has an excellent appearance design. The rubber mixture is made of a composition containing 5 to 20 parts by mass of small platelet mica as a metallic compounding agent and 0.05 to 10 parts by mass of a coloring pigment per 100 parts by mass of the total rubber components. The rubber mixture is intended to provide a rubber mixture for colored bicycle tires which have high abrasion resistance during riding, do not peel off the outer surface of the tire during use, and have a metallic color that is fashionable and has an excellent appearance design.

[0005] Patent Document 3 discloses a tire having at least one collar portion, the collar portion of which has a highly impermeable barrier layer and a polyurethane paint on the barrier layer, with the aim of providing a tire having at least one collar portion.

[0006] Patent Document 4 discloses a rubber composition for tires reinforced with titanium oxide, which comprises at least (i) one diene elastomer, (ii) one white filler as a reinforcing filler, and (iii) one coupling agent (white filler / elastomer), with all or part of the white filler in the composition being produced from titanium oxide having a particle size within a specific range.

[0007] JP 2000-38477 A JP 2002-128959 A WO2013 / 093895 WO00 / 073372

[0008] However, tires using the tire tread rubber composition described in Patent Document 1 have the drawback of poor tire wear. Furthermore, the colored bicycle tire described in Patent Document 2 is a metallic color tire and is limited to metallic colors, making it impossible to produce stylish colored tires. Furthermore, the tire described in Patent Document 3 has the problem of cracks and peeling in the barrier layer and polyurethane coating. Furthermore, the rubber composition described in Patent Document 4 contains a high proportion of petroleum-derived materials, and although the rubber is reinforced with titanium oxide, sufficient tire wear is not achieved.

[0009] On the other hand, the use of small mobility devices such as electric scooters and electric assist bicycles has become widespread, and there is a demand for fashion and design more than ever before. Also, in order to realize a sustainable society in various fields, there is a shift to environmentally friendly materials and the use of materials that emit less CO during use. ２ Efforts to reduce CO2 emissions are required.

[0010] In view of the above circumstances, the present invention has an object to provide a rubber composition for tires that can improve tire wear resistance while satisfying the demands for fashionability and design. Another object of the present invention is to provide a rubber composition for tires that allows for a wide range of options when coloring tires and has excellent durability.

[0011] As a result of intensive research into achieving the above-mentioned object, the inventors have found that the above-mentioned problems can be solved by a rubber composition for tires, which is prepared by uniformly dispersing a bio-rubber reinforcement material containing cellulose nanofibers and a silane coupling agent in a diene-based rubber using a kneader while heating, and then adding other tire compounding materials such as a non-carbon black filler and kneading the mixture, and by a tire using this rubber composition for tires.

[0012] That is, the rubber composition for tires includes at least a diene-based rubber, a bio-rubber reinforcement material, and a non-carbon black filler.

[0013] The present invention provides a rubber composition for tires that can improve tire wear resistance while meeting fashion and design requirements, and also provides a rubber composition for tires that allows for a wide range of options when coloring tires and has excellent durability.

[0014] 1 is a front view of a solid tire;

[0015] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0016] (Definition of Terms) Here, the main terms used in the present invention are defined. In this specification, the term "biomaterial" is a general term that refers to components of a rubber composition for a tire, primarily including natural rubber and bio-rubber reinforcements. When calculating the "biomaterial ratio," lubricants, processing aids, and the like that are compounded to improve the fluidity, etc., of natural rubber are also included in the calculation as "biomaterials." In this specification, the term "petroleum-derived material" is a general term that refers to components of a rubber composition for a tire, primarily including diene-based rubbers other than natural rubber and carbon black. When calculating the "petroleum-derived material ratio," lubricants, processing aids, and the like that are compounded to improve the fluidity, etc., of diene-based rubbers other than natural rubber are also included in the calculation as "petroleum-derived materials." In this specification, the term "inorganic chemical material" is a general term that refers to inorganic materials that are components of a rubber composition for a tire and are widely used as additives, etc., for rubber compositions for tires. Furthermore, the term "organic chemical material" in this specification is a general term for materials other than inorganic materials that are constituents of a rubber composition for a tire and are widely used as additives for the rubber composition for a tire, etc. Furthermore, the ratio of various materials is a value (%) obtained by dividing the total amount of the various materials by the total amount of the rubber composition for a tire.

[0017] The present invention relates to a rubber composition for tires, which has a biomaterial ratio of 32 to 54%, a petroleum-derived material ratio of 1 to 22%, an organic chemical material ratio of 16 to 17%, and an inorganic chemical material ratio of 29 to 30%.

[0018] As the bio-rubber reinforcement, a mixture of water-dispersed cellulose nanofibers and a thermoplastic resin dispersion, which has been dried, can be used. Specifically, nanoforest-PDP (manufactured by Chuetsu Pulp Industries Co., Ltd.), which is described in Japanese Patent No. 7175429, Japanese Patent No. 7109813, or Japanese Patent No. 6704551, can be suitably used. As the thermoplastic resin dispersion, a mixture of water-dispersed cellulose nanofibers and a biodegradable thermoplastic resin dispersion, such as polylactic acid resin or bio-polybutyl succinate (PBS), and dried can be used as the bio-rubber reinforcement, thereby further increasing the biomaterial ratio and reducing CO２ Furthermore, the biodegradability of tire wear dust will be improved.

[0019] Furthermore, bio-rubber reinforcement is white, has excellent rubber reinforcement and adsorption properties, and exhibits good color development for colorants. This makes it possible to produce colored tires with high design appeal and good fashionability. Furthermore, by using bio-rubber reinforcement in combination with non-carbon black fillers such as silica and zinc oxide, rubber with strength comparable to that of rubber reinforced with carbon black can be obtained. Furthermore, because the bio-material ratio can be increased, CO ２ Furthermore, the tire wear dust generated during driving is more biodegradable than conventional black tires containing carbon black because it contains a high proportion of biomaterials.

[0020] As the diene rubber, natural rubber or synthetic rubber such as isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, or acrylonitrile butadiene rubber can be used. Furthermore, as the natural rubber, RSS3, SVR10, SVR20, SVR3L, SVR10CV, SVRCV50, SVRCV60, SMR5, SMR20, SMR50, STR10, STR20, STR5, STRL, SIR10, SIR20, SIR5, SIRL, etc. can be used, and the most suitable one can be selected depending on the application based on the place of origin, price, and quality. Furthermore, when natural rubber is used as the diene rubber, the biomaterial ratio increases, which reduces CO₂, a cause of global warming. ２ In addition, the tire wear dust from tires made with natural rubber has a high biomaterial content and is more biodegradable than conventional tires.

[0021] Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropylmethyldiethoxysilane, 3-acryloxypropyltriethoxysilane, and Examples of usable compounds include acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltrialkoxysilane, 3-isocyanatepropyltriethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, and 3-octanoylthiopropyltriethoxysilane. The most suitable one can be selected depending on the compatibility between the filler and the rubber, and they may be used alone or in combination of two or more.

[0022] Examples of non-carbon black fillers that can be used include silica, zinc oxide, calcium carbonate, etc. These may be used alone or in combination of two or more.

[0023] As the colorant, organic pigments, inorganic pigments, titanium oxide, iron oxide, cerium oxide, natural material colorants, and the like can be used. As natural colorants, coconut shell powder, tea leaf powder, coffee grounds powder, and the like can be used. These are naturally derived components, which further reduce the environmental impact. In addition, to increase the whiteness of the rubber composition for tires, titanium oxide may be compounded in a proportion of 0.1 parts by mass or more and 10 parts by mass or less. If the amount is more than 10 parts by mass, the strength may decrease and the cost will increase. By making the rubber composition for tires white, it can be colored in various colors.

[0024] Antiaging agents that can be used include the monophenol-based Nocrac SP-N, the bisphenol-based Nocrac NS-30, the aromatic secondary amine-based Nocrac CD, the benzimidazole-based Nocrac MB, the paraffin wax Sunnock, the plant-based carnauba wax, rice wax, soybean wax, and the animal-based beeswax. Considering the risk of leakage into the ocean, a combination of the non-polluting Nocrac SP-N and the paraffin wax Sunnock is preferred, and each can be used within a range that does not impair the properties of the rubber per 100 parts by mass of rubber. Furthermore, plant-based waxes are best for reducing environmental impact.

[0025] As an additive, oil is preferably added as a plasticizer for rubber to improve crack resistance. Examples of oil include mineral oil, vegetable oil, and mixtures thereof, but vegetable oil is preferred to reduce environmental impact, and preferred are drying oils such as linseed oil, tung oil, dehydrated castor oil, semi-drying oils such as rice bran oil, soybean oil, rapeseed oil, sunflower oil, peanut oil, corn oil, non-drying oils such as castor oil, palm oil, coconut oil, olive oil, etc.

[0026] Suitable vulcanizing agents include sulfur, organic peroxides, metal oxides, organic amine compounds, peroxides, and resin vulcanizing agents.

[0027] Examples of vulcanization accelerators that can be used include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD) and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-oxyethylene-2-benzothiazolesulfenamide and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-orthotolylguanidine and orthotolylbiguanidine. These may be used alone or in combination of two or more.

[0028] Antistatic agents may be added as needed when producing non-carbon black filled rubber, and examples of such agents that can be used include Kao's Elestmaster HE-510, Electrostripper TS-5, and Emazol L-10V, and NOF's Elegan 264WE and Ekegan 264WAX.

[0029] In addition to the above-mentioned components, the rubber composition for tires of the present invention may contain other known components to the extent that the intended effect is not impaired. Specific examples of components that can be used to improve kneading properties include zinc oxide, stearic acid, a fatty acid ester mixture, a coumarone resin, an indene resin, a styrene copolymer resin, and a fatty acid ester. Addition of these components reduces adhesion of the rubber to the rolls, improving kneading properties.

[0030] (Method for Producing Rubber Composition for Tires) A ​​natural rubber composition is obtained by uniformly dispersing 10 to 60 parts by mass of biorubber reinforcement per 100 parts by mass of natural rubber using a conventional kneader, such as a Banbury mixer, pressure kneader, or two-roll mill. The remaining tire rubber composition components, including diene rubber, non-carbon black filler, colorant, silane coupling agent, antioxidant, antistatic agent, and other additives, are then added to obtain a natural rubber composition at a ratio of 1 to 20 parts by mass of biorubber reinforcement per 100 parts by mass of natural rubber. The mixture is then uniformly kneaded at a temperature above the melting point of the thermoplastic resin of the biorubber reinforcement, followed by the addition of a vulcanizing agent, vulcanization accelerator, foaming agent, expanding agent, and other additives to produce a colored tire rubber composition. It is more preferable to incorporate 2 to 12 parts by mass of biorubber reinforcement. The rubber kneading temperature after adding the vulcanizing agent, vulcanization accelerator, foaming agent, expanding agent, and other additives depends on the properties of the materials, but is preferably 60 to 80°C.

[0031] (Method for manufacturing a solid mobility tire) A solid mobility tire can be manufactured by a general method using the rubber composition for a tire according to the present invention. Specifically, the tire can be manufactured by charging the rubber composition for a tire according to the present invention into a mold and subjecting it to hot press vulcanization molding. Furthermore, by subjecting the tire to press vulcanization molding in a mold having a space in the circumferential portion, a lightweight solid mobility tire having a space in the sidewall portion of the solid tire shown in FIG. 1 can be manufactured.

[0032] To reduce the weight of mobility solid tires, it is recommended to use a low-density tire rubber composition. When creating a low-density tire rubber composition, it is recommended to add a foaming agent or an expanding agent. Examples of foaming agents that can be used include Cellmike A and Celton NP, and expanding agents include Microsquare FN-100M and FN-78. Adding 1 to 10 parts by mass of these foaming agents and expanding agents to 100 parts by mass of rubber and vulcanizing the resulting mixture produces a low-density, sponge-like solid tire with a rubber density of 0.5 to 1.1, improving impact resistance. The presence of cellulose nanofibers allows for the miniaturization and uniformity of foam cells, which is expected to improve strength. Furthermore, a vulcanization temperature of 140°C to 160°C for 20 minutes is preferred.

[0033] (Method for Manufacturing Mobility Pneumatic Tire) A mobility pneumatic tire can be manufactured using the rubber composition for tires according to the present invention by a general manufacturing method known for manufacturing bicycle tires, wheelchair tires, motorcycle tires, automobile tires, etc. These can be used for the rubber of the tread portion, sidewall portion, and shoulder portion shown in FIG.

[0034] If a rubber composition for tires containing biorubber reinforcement is used only in the tread portion of a mobility air tire or a mobility solid tire, it is preferable because it makes it easy to determine the wear state of the tread portion and makes it easy to determine when to replace the tire.

[0035] Using solid and air mobility tires with a high biomaterial ratio, such as the biorubber reinforcement, non-carbon black filler, and biomaterial-derived colorant of the present invention, it is possible to manufacture vibrantly colored tires with high fashionability and design. Furthermore, the reinforcing effect of the biorubber reinforcement improves the rebound resilience, reduces rolling resistance, and increases the driving distance per full charge. Furthermore, the reduced compression set reduces tire deformation while stopped. Furthermore, it replaces the reinforcing effect of carbon black, allowing for the production of durable colored tires. By increasing the biomaterial ratio in the tire raw materials, the tire becomes carbon-neutral, reducing CO2 emissions from tire materials and during driving. ２ In addition, the high biodegradability of tire wear dust can contribute to reducing marine pollution.

[0036] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0037] (Examples 1 to 4) 24 parts by mass of a bio-rubber reinforcement (nanoforest-PDP-N34) and 1 part by mass of stearic acid were kneaded with 100 parts by mass of natural rubber in a pressure kneader at a temperature above the melting point of the thermoplastic resin of the bio-rubber reinforcement to produce (1) a natural rubber composition in which the bio-rubber reinforcement was dispersed. The resulting natural rubber composition was blended with (2) tire compounding materials, including a diene rubber, a non-carbon black filler, a colorant (or colorants), a silane coupling agent, antioxidant A, antioxidant B, and additives, so that the bio-rubber reinforcement was present in an amount of 3 to 12 parts by mass per 100 parts by mass of the rubber component, and kneaded in a pressure kneader at 150°C. After uniform kneading, a vulcanizing agent, vulcanization accelerator A, and vulcanization accelerator B were added, and the mixture was further kneaded at temperatures between 60°C and 80°C to produce tire rubber compositions according to Examples 1 to 4 and Comparative Examples 1 and 2 in Table 1. Next, this tire rubber composition was vulcanized and molded in a mold to prepare cylindrical test pieces measuring 12.5 mm and an outer diameter of 29.5 mm, and a rubber sheet 2 mm thick was punched out with a No. 3 dumbbell mold to prepare dumbbell test pieces. For running tests, a solid tire was manufactured by hot press vulcanization molding in a 5.5-inch solid tire mold, and the solid tire was press-fitted into a wheel to prepare a test wheel.

[0038] The following products were used for (1) the natural rubber composition and (2) the tire compounding material. (1) Natural rubber composition Natural rubber (SMR-L) Bio-rubber reinforcement agent (nanoforest-PDP-N34: Chuetsu Pulp & Paper Co., Ltd.) Stearic acid (Tsubaki: NOF Corporation) (2) Tire compounding materials Diene rubber (butadiene rubber BR01: ENEOS Materials Corporation) Non-carbon black filler (precipitated silica Nipsil AQ: Tosoh Silica Corporation) Colorant (cerium oxide: Resonac Co., Ltd.) Silane coupling agent (Si69: Evonik LLC) Anti-aging agent A (Nocrac SP-N: Ouchi Shinko Chemical Co., Ltd.) Anti-aging agent B (Sunnock: Ouchi Shinko Chemical Co., Ltd.) Additive (PEG #4000: NOF Corporation) Processing aid (Coumarone G-90: Nitto Chemical Co., Ltd.) Additives: (Process oil (SNH-22): Sankyo Yuka Kogyo Co., Ltd.) Vulcanization accelerator: (Noccela: Ouchi Shinko Chemical Industry Co., Ltd.) Additives: (Zinc oxide: Seido Chemical Industry Co., Ltd.) Vulcanizing agent: (HK-200-5: Hosoi Chemical Industry Co., Ltd.)

[0039] The dumbbell specimens were subjected to the DeMatia repeated fatigue test ("Vulcanized rubber and thermoplastic rubber - Determination of flex crack resistance and flex crack growth resistance (DeMatia method)": JIS K6260:2017), tensile strength (Vulcanized rubber and thermoplastic rubber - Determination of tensile properties) JIS K6251:2017), rebound resilience ("Vulcanized rubber and thermoplastic rubber - Determination of rebound resilience": JIS K6255:2013), A-type rubber hardness ("Vulcanized rubber and thermoplastic rubber - Determination of hardness": JIS K6253:2012), and compression set ("Vulcanized rubber and thermoplastic rubber - Determination of compression set at room temperature, high temperature, and low temperature": JIS K 6262:2013). The results are shown in Table 2.

[0040] The 5.5-inch solid tire wheels were attached to the front and rear wheels of a small electric scooter, and the scooter was driven 100 km at a maximum speed of 6 km / h with a rider weighing 65 kg and a body load of 25 kg, for a total load of 90 kg. After the drive, the appearance, power consumption, and wear of the tires were measured. The results are shown in Table 2.

[0041] The appearance of the tires after running was evaluated according to the following evaluation criteria: ⊚: absolutely no cracks or chips in the tire rubber; ◯: no harmful cracks or chips in the tire rubber; △: slight cracks or chips in the tire rubber; ×: significant cracks or chips in the tire rubber.

[0042] The amount of wear was measured as follows: The amount of wear was calculated by subtracting the weight of the tire after 100 km of running from the weight of the tire before running. After running, the tire was washed with water because it had become dirty, and then dried and the weight was measured.

[0043] The dispersibility of the bio-rubber reinforcement was evaluated by visually checking for the presence or absence of CNF clumps in images taken with a micro X-ray CT device and using the following evaluation criteria. The results are shown in Table 2. ⊚: 10 μm clumps in a 0.7 mm x 0.7 mm area in a visually observed image. ２ 〇: Visual inspection of image shows 10μm or less in an area of ​​0.7mm x 0.7mm. ２ △: Visually inspected image shows 10 μm or less in an area of ​​0.7 mm × 0.7 mm ２ x: Visually inspected image shows 100 μm particles in an area of ​​0.7 mm x 0.7 mm. ２ XX: Visually inspected image shows 100 μm particles in an area of ​​0.7 mm x 0.7 mm. ２ There are more than 100 lumps like this.

[0044] Regarding the biodegradability of tire wear dust, 1 g of tire wear dust was collected by scraping off a tire with a grinder, and placed in a sealed storage bottle together with 250 g of seawater. The dust was then stored at 30°C for 60 days. After that, the dust was stored in a sealed storage bottle together with 250 g of seawater at 30°C. ２ The CO2 concentration in the storage bottle was measured using a concentration meter (PORTABLE CO2 METER AX7755). ２ The concentrations were measured and evaluated according to the following evaluation criteria: ⊚: CO2 increased by 1000 ppm or more; ◯: CO2 increased by 500 ppm or more; Δ: CO2 increased by 100 ppm or more; ×: no difference.

[0045]

[0046]

[0047] The tire of Comparative Example 1 is a conventionally manufactured black solid tire, and although it has good running performance and manufacturing costs, it has a high carbon content in the material and produces CO ２ The amount of CO emissions was high. On the other hand, the black solid tire of Comparative Example 2, which used a small amount of carbon black as a colorant, showed poor results in tire wear and power consumption in the running test. The tires of Examples 1 to 4, to which the bio-rubber reinforcement was added, showed improved power consumption in the running test compared to the comparative examples. In addition, tire wear was reduced, and performance was equal to or better than that of conventional black tires. Furthermore, improvements in tire wear and power consumption were observed in proportion to the ratio of bio-rubber reinforcement. Furthermore, the bio-material ratios of Examples 1 to 3 were higher than those of Comparative Examples 1 and 2, and CO ２ The diene rubber of Example 4, which was made entirely of natural rubber, had an even higher biomaterial ratio, and achieved performance in terms of tire wear and electricity consumption that was equal to or better than that of the conventional black tire of Comparative Example 1. This color tire with a higher biomaterial ratio was able to reduce CO ２ This can significantly reduce carbon dioxide emissions, and tire wear dust is expected to be biodegradable. Tires reinforced with this non-carbon black filler and bio-rubber reinforcement have a higher rebound elasticity and reduced rolling resistance. If these tires are used on electrically assisted bicycles, electric kick scooters, small electric vehicles, etc., the driving distance per full charge will be longer and the power consumed during driving will be reduced. Furthermore, the reduced compression set is thought to reduce tire deformation while the vehicle is stopped.

[0048] 1: tread portion, 2: sidewall portion, 3: space in sidewall portion, 4: tread portion, 5: shoulder portion, 6: sidewall portion

[0049] The rubber composition for tires, produced using a general rubber mixer from the diene rubber of the present invention, bio-rubber reinforcement, silane coupling agent, non-carbon filler, colorant (or colorants), wax, oil, vulcanizing agent, antioxidant, antistatic agent, additives, and vulcanization accelerator, was developed for use in mobility tires, but can also be used for rubber products other than mobility tires, such as automobile wipers, automobile weather strips, ship fenders, fenders, printer rubber rollers, printing press rollers, coating machine rolls, rubber gloves, rubber packing, and vibration-proof rubber.

Claims

1. A rubber composition for tires, comprising at least a diene rubber, a bio-rubber reinforcing agent, and a non-carbon black filler.

2. A rubber composition for tires, comprising at least a diene rubber, a bio-rubber reinforcing agent, and a non-carbon black filler, wherein the bio-rubber reinforcing agent contains cellulose nanofibers.

3. The rubber composition for tires according to claim 1, wherein the diene rubber is natural rubber and synthetic rubber, and the ratio of petroleum-derived materials in the rubber composition for tires is 21% or less.

4. The rubber composition for tires according to claim 2, wherein the diene rubber is natural rubber and synthetic rubber, and the ratio of petroleum-derived materials in the rubber composition for tires is 21% or less.

5. The rubber composition for tires according to claim 1, wherein the diene rubber is natural rubber, and the ratio of petroleum-derived materials in the rubber composition for tires is 21% or less.

6. The rubber composition for tires according to claim 2, wherein the diene rubber is natural rubber, and the ratio of petroleum-derived materials in the rubber composition for tires is 21% or less.

7. The rubber composition for tires according to any one of claims 1 to 6, wherein 0.1 to 10 parts by mass of titanium oxide is blended.

8. A colored pneumatic tire using the rubber composition for tires according to any one of claims 1 to 6.

9. A colored pneumatic tire using the rubber composition for tires according to claim 7.

10. A colored solid tire using the rubber composition for tires according to any one of claims 1 to 6.

11. A colored solid tire using the rubber composition for tires according to any one of claims 7.

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