Method for preparing rubber composition, rubber composition prepared by the method, and tire manufactured using the same

Abstract

The present invention relates to a method for preparing a rubber composition capable of improving the physical properties of a final product. In order to achieve the purpose of the present invention, the present invention provides a method for preparing a rubber composition, comprising the step of preparing a polymer-dispersed rubber composition in which a polymer is dispersed in a rubber in a solution phase, wherein the step of preparing the polymer-dispersed rubber composition comprises: in a rubber preparation process, a step of polymerizing a rubber composition comprising a monomer, a solvent and a catalyst, recovering residual monomers, and then adding a polymer to the rubber solution remaining after recovering the residual monomers. When the rubber composition prepared as above is applied to a tire tread composite material, durability, grip, and low rotational resistance can be improved, and excellent braking characteristics, low fuel consumption characteristics, and improved wear resistance can be obtained.

Description

Technical Field

[0001] The invention relates to a method for preparing a rubber composition capable of improving the physical properties of a final product. Background Art

[0002] Generally, products using rubber include tires, shoe soles, belts, hoses, sheets, sealants, and adhesives that require excellent adhesion and require excellent durability.

[0003] In order to finally complete this product, reinforcing agents, additives and other processing aids are generally directly put into a mixer together with the rubber as a raw material and mixed into a bulk state, or mixed together after preparing a masterbatch to produce the final rubber composite product.

[0004] For example, regarding the improvement of rubber compositions for tire treads, Korean Patent No. 10-1276654 previously disclosed a masterbatch elastomer, a rubber composition for tire treads containing the same, and a tire manufactured using the same, wherein the masterbatch elastomer contains 50 to 150 parts by weight of a reinforcing agent and 50 to 150 parts by weight of polybutene (PIB) relative to 100 parts by weight of raw rubber, so that the polybutene (PIB) originally used as free oil of the rubber composition for tire treads is included in the masterbatch elastomer to prepare the masterbatch elastomer. By using this masterbatch elastomer, the overall content of polybutene (PIB) in the tread rubber composition can be increased, solving the processability problem caused by excessive use in the rubber composition for tire treads, improving the tire's grip performance and maintaining the grip performance continuously.

[0005] However, in order to improve the dispersibility of the filler, this method uses raw rubber, filler, and polybutene (PIB) to prepare a masterbatch elastomer. However, this method is also difficult to handle liquid polybutene (PIB) having adhesiveness, just like the case of using polybutene (PIB) as free oil, and it takes a lot of time and energy to prepare a masterbatch elastomer containing 50 phr or more of polybutene (PIB).

[0006] Therefore, a new preparation method is needed that can improve the physical properties of the final rubber product while simplifying the process and improving the performance without increasing the preparation cost. Summary of the invention

[0007] Technical issues

[0008] The object of the present invention is to provide a method for preparing a rubber composition which has a simple process and can greatly improve the physical properties of the final product while minimizing the need to change existing equipment.

[0009] Another object of the present invention is to provide a rubber composition having improved properties required for each product.

[0010] In addition, another object of the present invention is to provide a tire having improved physical properties.

[0011] Technical means

[0012] To achieve the purpose of the present invention, the present invention provides a method for preparing a rubber composition, the method being used for preparing a polymer dispersed rubber composition in which a polymer is dispersed in a rubber (polymer extended rubber) in a solution phase, comprising: in a rubber preparation process, a step of recovering residual monomers after a rubber composition comprising a monomer, a solvent and a catalyst is polymerized; and a step of adding a polymer to the rubber solution remaining after the residual monomers are recovered and uniformly dispersing the polymer in the solution phase. According to one embodiment of the present invention, the polymer is preferably C 4～9 The polymer has a weight average molecular weight of 300 to 20,000 g / mol and can be added in an amount of 0.1 to 100 phr (per hundred parts of rubber content) relative to the rubber content, preferably 1 to 50 phr.

[0013] According to an embodiment of the present invention, the polymer is preferably a C4, C5, or C9 polymer.

[0014] According to an embodiment of the present invention, the monomer is preferably one or more selected from the group consisting of styrene, butadiene, isobutylene, isoprene, ethylene and propylene.

[0015] In one embodiment of the present invention, the rubber is preferably a polyolefin elastomer (POE) such as emulsion butadiene styrene rubber (ESBR), solution butadiene styrene rubber (SSBR), styrene-butadiene-styrene rubber (SBS), styrene-ethylene-butadiene-styrene rubber (SEBS), butadiene rubber (BR), butyl rubber (IR), isoprene-isobutylene rubber (IIR) or ethylene propylene rubber (EPM), ethylene propylene diene monomer rubber (EPDM).

[0016] According to an embodiment of the present invention, the rubber composition is preferably used as a rubber composition for tire tread, a rubber composition for sealant, or a rubber composition for hot melt adhesive.

[0017] To achieve another object of the present invention, the present invention provides a rubber composition for tire tread comprising the rubber composition prepared according to the present invention.

[0018] To achieve another object of the present invention, a tire manufactured using the rubber composition for tire tread of the present invention is provided.

[0019] Effects of the Invention

[0020] The rubber composition prepared according to the present invention can improve the physical properties of the final rubber product.

[0021] In addition, a tire manufactured using the rubber composition for tire tread prepared according to the present invention has improved processability, grip (wet road grip), fuel efficiency, and wear resistance.

[0022] In addition, the method for preparing the rubber composition of the present invention can utilize existing equipment and significantly improve the physical properties of the rubber product, can greatly reduce costs, and is also excellent in environmental protection.

[0023] Best Mode for Carrying Out the Invention

[0024] The present invention is described in more detail below, but this is only for describing the present invention and should not be interpreted as a method of limiting the scope of the present invention.

[0025] The present invention provides a method for preparing a rubber composition, comprising the steps of preparing a polymer liquid phase dispersed rubber composition in which a polymer is dispersed in a rubber in a solution phase, wherein the steps of preparing the polymer liquid phase dispersed rubber composition include: in a rubber preparation process step, a step of polymerizing a rubber composition containing a monomer, a solvent and a catalyst and then recovering the residual monomer; a step of adding a polymer into the rubber solution remaining after recovering the residual monomer and uniformly dispersing the polymer in the solution phase; and a step of curing, drying and molding the rubber / polymer mixed solution by removing the solvent.

[0026] <Polymer Liquid Dispersed Rubber Composition>

[0027] The difference between the present invention and the prior art lies in the step of adding the polymer and the properties of the added polymer.

[0028] That is, in the present invention, when preparing the rubber composition, the polymer is not directly mixed with the rubber, but must go through the following steps, namely, after removing the residual monomers remaining after the reaction in the rubber preparation process, the polymer is added in the remaining rubber solvent state, and the polymer exists in the form of being dispersed in the rubber solution.

[0029] Only when the rubber is prepared using a rubber composition in which the polymer is dispersed in a liquid phase as described above, can desired physical properties be obtained when preparing the final rubber product.

[0030] The solvent can mainly be hydrocarbon organic solvents such as n-hexane, cyclohexane, mixed heptane, etc.

[0031] The desired final properties vary depending on the type of final rubber product. For example, when a tire tread is the final rubber product, excellent braking properties and low fuel consumption properties are required, so durability, grip, and low rotational resistance are important.

[0032] Therefore, in the present invention, when a tire tread is to be manufactured, a rubber composition for manufacturing a tire tread needs to be prepared, and when preparing the rubber composition for the tire tread, a step of dispersing a polymer such as polybutene (PIB) in a liquid phase in a rubber to be used to prepare a polybutene (PIB) liquid phase dispersed rubber composition needs to be included. The rubber that can be used when manufacturing a tire tread can be a synthetic rubber or a mixture of a natural rubber and a synthetic rubber.

[0033] The natural rubber may be ordinary natural rubber or modified natural rubber.

[0034] Any known natural rubber can be used as the ordinary natural rubber, and there is no limitation on the origin, etc. The natural rubber contains cis-1,4-polyisoprene as the main body, but may also contain trans-1,4-polyisoprene according to the required properties. Therefore, in addition to the natural rubber containing cis-1,4-polyisoprene as the main body, the natural rubber containing trans-1,4-isoprene as the main body may also be included, such as balata, one of the rubbers of the Sapotaceae family in South America.

[0035] The modified natural rubber refers to a rubber obtained by modifying or refining the ordinary natural rubber. For example, the modified natural rubber may be epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), hydrogenated natural rubber, or the like.

[0036] The synthetic rubber may be selected from the group consisting of styrene butadiene rubber (SBR), modified styrene butadiene rubber, butadiene rubber (BR), modified butadiene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, silicone rubber, nitrile rubber, hydrogenated nitrile rubber, nitrile butadiene rubber (NBR), modified nitrile butadiene rubber, styrene butadiene styrene rubber (SBS), styrene ethylene butadiene styrene (SEBS) rubber, ethylene propylene rubber (EPM), ethylene propylene diene monomer (EPDM) rubber, hepalon rubber, chloroprene rubber, ethylene vinyl acetate rubber, acrylic rubber, alcohol rubber, vinylbenzylchlorostyrene butadiene rubber, bromomethylstyrene butyl rubber, maleic acid styrene butadiene rubber, carboxylic acid styrene butadiene rubber, epoxy isoprene rubber, maleic acid ethylene propylene rubber, carboxylic acid nitrile butadiene rubber, brominated polyisobutyl isoprene-co-p-methylstyrene Any one of the group consisting of isoprene-coparamethylstyrene, BIMS) and combinations thereof.

[0037] The polymer may use polybutene (PIB), and preferably, polybutene with a number average molecular weight of 150 to 5000 g / mol may be used as the highly reactive polybutene (PIB). Since the carbon-carbon double bond of the highly reactive polybutene (PIB) is mainly located at the end of the polybutene (PIB), the bonding property with the raw rubber increases during the reaction, and compared with the existing polybutene (PIB), it plays a favorable role in durability. As described above, different polymers may also be used according to the desired physical properties of the final rubber product.

[0038] According to one embodiment of the present invention, the polymer is preferably C 4～9 The polymer has a weight average molecular weight of 300 to 20,000 g / mol, and is added in an amount of 0.1 to 100 phr (per hundred parts of rubber content) relative to the rubber content, preferably 1 to 50 phr.

[0039] If the polymer is contained in an amount of less than 1 phr relative to the rubber content, the physical properties of the final rubber product cannot be significantly improved, and if it is contained in an amount of more than 50 phr, the original physical properties of the rubber cannot be exhibited.

[0040] According to an embodiment of the present invention, the polymer is preferably a C4, C5, or C9 polymer, and more preferably a C4 polybutene (PIB).

[0041] When using synthetic rubber, since an organic solvent is used, after removing the residual monomers as shown in the previous method, polybutene (PIB) is directly added to a storage tank or a mixing tank and mixed, and then after a productization process, a rubber in which the polymer is dispersed in a liquid phase can be obtained.

[0042] According to an embodiment of the present invention, the monomer is preferably one or more selected from the group consisting of styrene, butadiene, isobutylene, isoprene, ethylene and propylene.

[0043] In one embodiment of the present invention, the rubber is preferably a polyolefin elastomer (POE) such as emulsion butadiene styrene rubber (ESBR), solution butadiene styrene rubber (SSBR), styrene-butadiene-styrene rubber (SBS), styrene-ethylene-butadiene-styrene rubber (SEBS), butadiene rubber (BR), butyl rubber (IR), isoprene-isobutylene rubber (IIR) or ethylene propylene rubber (EPM), ethylene propylene diene monomer rubber (EPDM).

[0044] According to an embodiment of the present invention, the rubber composition is preferably used as a rubber composition for tire tread, a rubber composition for sealant, or a rubber composition for hot melt adhesive.

[0045] Particularly preferably, when the rubber is isoprene-isobutylene rubber (IIR), it can be used as butyl rubber for sealants.

[0046] In addition, particularly preferably, when the rubber is a styrene-butadiene-styrene block copolymer (SBS) and a styrene-ethylene-butadiene-styrene resin (SEBS), it can be used to prepare a hot melt adhesive.

[0047] To achieve another object of the present invention, the present invention provides a rubber composition for tire tread comprising the rubber composition prepared according to the present invention.

[0048] According to one example of the present invention, the rubber composition for tire tread may contain, in addition to the raw rubber and highly reactive polybutene (PIB), rubber compounding ingredients generally used in rubber compositions for tire treads, including silica and / or carbon black as reinforcing fillers, processing oil as a softener, sulfur as a vulcanizing agent, CBS and 1,3-diphenylguanidine (DPG) as vulcanization accelerators, zinc oxide as a vulcanization activator, stearic acid, a coupling agent and an antioxidant for improving dispersibility, and the like.

[0049] The type of silica that can be used as a reinforcing filler in the present invention is not particularly limited, but preferably has a surface area of ​​175±5 m2 / g, a moisture content of 6.0±0.5% by weight, and a silica (SiO2) content of 90% by weight or more.

[0050] The type of carbon black used in the present invention is not particularly limited, and preferably has a BET (Brunauer, Emmett, Teller) specific surface area of ​​80 to 90 m2 / g, a DBP (di-n-butyl phthalate) adsorption value of 100 to 110 g / 100 g, and an iodine adsorption value of 90 to 120 mg / g. Preferably, the carbon black is used in an amount of 40 to 100 parts by weight relative to 100 parts by weight of the raw rubber. If the amount used is less than 40 parts by weight, sufficient reinforcement effect cannot be achieved, and thus it is not recommended. If it exceeds 100 parts by weight, heat generation and wear resistance effects cannot be achieved, and thus it is not recommended.

[0051] The processing oil plays a role of a softener, and preferably contains 5 to 25% by weight of aromatics, 25 to 45% by weight of naphthalene, and 35 to 65% by weight of paraffin. As for the other various additives used in the present invention, they are common components used in the rubber composition for tire treads and are not described in detail.

[0052] As described above, the rubber composition for tire tread of the present invention can improve the grip performance of the tread portion of automobile tires, especially high-speed racing tires, without affecting the basic physical properties of the tires, and can continuously maintain such performance.

[0053] To achieve another object of the present invention, a tire manufactured using the rubber composition for tire tread of the present invention is provided. DETAILED DESCRIPTION

[0054] The present invention is described in more detail below with reference to specific embodiments and comparative examples, which are only used to describe the present invention more easily and should not be construed as limiting the scope of the present invention.

[0055] Preparation Example 1: Preparation of polybutene (PIB) in liquid phase dispersion (extension) of butadiene rubber (BR)

[0056] After adding 1500g of 1,3-butadiene and 5250g of hexane from which water has been removed to a 10L autoclave reactor replaced with nitrogen, the reactor temperature was raised to 95°C while the agitator was used to rotate. After the temperature stabilized at 95°C, a combined catalyst of triisobutylaluminum / nickel oxalate / hydrofluoric acid was added, and the polymerization of polybutadiene rubber (BR) was carried out for 2 hours while adjusting the temperature so that the temperature did not rise rapidly. Then, 2.5g of alkyl phosphate compounds and 5g of phenolic antioxidants were added as reaction terminators to terminate the reaction. The polymerized polymer was cooled to 50°C and the pressure was released to prepare a butadiene rubber / hexane solution from which residual 1,3-butadiene was removed. The prepared butadiene rubber / hexane solution was measured and transferred to a 5L mixing tank with a stirrer after measuring the solid content (TSC, total solid content). After adding 37.5 phr of polybutene (PIB) shown in Table 1 to the butadiene rubber / hexane solution relative to the solid content, stirring was performed until the PIB was completely dissolved. The prepared butadiene rubber / polybutene / hexane mixture was stripped of hexane as a solvent to obtain a butadiene rubber solid in which the polybutene was uniformly dispersed, and the water content of the solid was dried using a processing roll at 100° C. to prepare a butadiene rubber sample in which 37.5 phr of PIB was dispersed (extension).

[0057] Comparative Preparation Example 1: Preparation of polybutadiene (BR)

[0058] Polybutadiene rubber (BR) was polymerized in the same manner as in Preparation Example 1, and residual 1,3-butadiene and the solvent were removed to obtain polybutadiene rubber (BR).

[0059] Comparative Examples 1 and 2

[0060] Comparative Example 1 used only the polybutadiene rubber prepared in Comparative Preparation Example 1, and Comparative Example 2 used a mixture of the polybutadiene prepared in Comparative Preparation Example 1 and HRPIB470 prepared by Hanwha Total Petrochemical Corporation.

[0061] Examples 1 to 5

[0062] In Examples 1 to 5, polybutadiene rubber (BR) was prepared according to Preparation Example 1, and after removing the monomer, different polybutenes (PIB) as shown in Table 1 were added to prepare butadiene rubber (BR) in which the polybutene (PIB) shown in Table 1 was dispersed (extension) in the liquid phase.

[0063] Information on raw materials used

[0064]

Table 1

[0065]

[0066] -PIB: Hanwha Total Petrochemical Co., Ltd. CPIB230, CPIB650, HRPIB190, HRPIB470

[0067] 1) CPIB230: conventional PIB (Mn 950 g / mol), PB950 (Daelin Industry Co., Ltd.)

[0068] 2) CPIB650: conventional PIB (Mn 1300 g / mol), PB1300 (Daelin Industry Co., Ltd.)

[0069] 3) HRPIB190: Highly active PIB (Mn 1000 g / mol), HRPB1000 (Daelin Industry Co., Ltd.)

[0070] 4) HRPIB470: Highly active PIB (Mn 1300 g / mol), HRPB1300 (Daelin Industry Co., Ltd.)

[0071] -Hx: Hanwha Total Petrochemical Co., Ltd. n-hexane

[0072] -CHx: Tokuyama Chemical Co., Ltd. cyclohexane

[0073] <Examples 1 to 6>

[0074] According to the components in Table 2, a pre-crosslinked composite material was prepared using MIX-LABO (mixing volume: 0.5 liter, main motor: 15 HP) produced by Moriyama Corporation.

[0075] In Examples 1 to 5 in Table 2, the BR dispersed with PIB uses a rubber (PIB-extended rubber) in which the polybutene (PIB) prepared in Preparation Example 1 is dispersed in a liquid phase, Comparative Example 1 uses only the polybutadiene rubber prepared in Comparative Preparation Example 1, and Comparative Example 2 uses a mixture of the polybutadiene rubber prepared in Comparative Preparation Example 1 and polybutene (PIB, HRPIB470).

[0076] The mixing is carried out in two steps. The first mixing is to add the rubber composition, filler (silicon dioxide), oil, zinc oxide (ZnO), stearic acid, silane coupling agent (Si-69) under the conditions of filling 75% of the volume of a 0.5-liter mixer and a rotor speed of 70 rpm, and control the temperature to obtain a primary rubber composition at 140-150°C.

[0077] In the second kneading, after cooling the kneaded product to room temperature, sulfur, DPG (diphenylguanidine), CBS (N-cyclohexyl-2-benzothiazolesulfonamide), and an antioxidant (6-PPD) were added at 90° C. or less, and kneaded at 50 rpm for 2 minutes.

[0078] In order to cross-link the kneaded rubber composite material, 2 minutes were added to the T90 time obtained by measuring the vulcanization characteristics using a rubber processing analyzer (RPA) at 160°C, 40 minutes, and a deformation rate of 1%. Each rubber composite material was cross-linked in a high-temperature press at 160°C according to the above time to prepare a rubber composite material sample for tire tread.

[0079] As other additives, 3 parts by weight of zinc oxide (ZnO), 2 parts by weight of stearic acid (St-A), 70 parts by weight of silica (ULTRASIL 7000Gr), 5.6 parts by weight of a silica coupling agent (SI-69), and 10 parts by weight of TDAE (treated aromatics extracted distillate) oil were added to 100 parts by weight of a rubber composition containing SBR, BR, and PIB to prepare a primary compound (SMB, silica masterbatch).

[0080] In addition to the primary compound, 1.5 parts by weight of sulfur, 1.8 parts by weight of diphenylguanidine (DPG) as a vulcanization accelerator, 1.8 parts by weight of cyclohexylbenzothiazolesulfenamide (CBS), and 0.2 parts by weight of an antioxidant (6PPD) were added to prepare a secondary compound (FMB, final masterbatch). However, in Example 5, the only difference is that the sulfur content is 1.8 parts by weight.

[0081] <Comparative Example 1>

[0082] A rubber composite material sample was prepared in the same manner as in Example 1 except that BR containing no polybutene (PIB) was used.

[0083] <Comparative Example 2>

[0084] According to the components in Table 1, a rubber composite material sample was prepared in the same manner as in Example 4, except that the polybutene (PIB) of HRPIB470 was directly added to the mixer and mixed with the rubber without the step of independently dispersing the polybutene (PIB) in the liquid phase.

[0085]

Table 2

[0086] (Unit: weight %)

[0087]

[0088] Experimental example:

[0089] The physical properties of each rubber composite material sample prepared according to the comparative example and the example were measured according to the relevant provisions of ASTM as shown below, and the results are shown in the following Table 3.

[0090] (1) Kneading viscosity (Mooney viscosity, MV): Mooney viscosity was measured using a Mooney viscometer (MV2000, Alpha Technologies) at 100° C. with a large rotor preheated for 1 minute and the value was read 4 minutes after the rotor was started.

[0091] (2) Hardness: A hardness test was conducted in accordance with JIS K6253 (2001), and the spring hardness HA (Shore A hardness) was measured.

[0092] (3) Modulus: The modulus measurement was carried out by cutting the specimen into a dumbbell shape using a tensile testing machine manufactured by Instron. The 100% and 200% moduli refer to the stress acting on the specimen when the specimen is stretched 100% and 200%, respectively.

[0093] (4) Tensile strength: For the tensile strength, a vulcanized rubber sheet was punched to prepare a No. 3 dumbbell test piece as described in JIS K6251 (2001). The test piece was subjected to a tensile test at a measuring temperature of 25° C. and a tensile speed of 500 mm / min in accordance with the method specified in JIS K6251, and the tensile stress at break TB and the elongation at break EB at 100% modulus (M100), 200% modulus (M200), and 300% modulus (M300) were measured.

[0094] (5) Elongation: When measuring the tensile strength, the degree of deformation (%) up to the breaking point was measured.

[0095] (6) Viscoelasticity: Viscoelasticity is measured using dynamic mechanical analysis (DMA). 0°C Tanδ is used as a proxy for tire braking performance on wet roads. A higher value indicates better performance. 60°C Tanδ is used as a proxy for tire rotational resistance. A lower value indicates better rotational resistance and improved fuel efficiency.

[0096] (7) Wear: Wear is measured using a DIN wear tester while applying a 5N load in accordance with the ASTM D5963 method to measure the weight loss caused by wear and tear. The value is expressed as a relative index. The larger the value, the better the wear resistance.

[0097]

Table 3

[0098]

[0099] As shown in Table 3, the samples prepared by dispersing PIB in the solution phase in rubber have improved durability, grip, and low rotational resistance compared to the samples without PIB or directly adding the same amount of PIB into the mixer, and achieved excellent braking characteristics, low fuel consumption characteristics, and improved wear performance.

Claims

1. A method for preparing a rubber composite material composition, characterized in that: include: A step of polymerizing a composition for preparing rubber comprising monomers, a solvent and a catalyst; a step of recovering residual monomers; A step of adding a polymer to the rubber solution remaining after recovering the residual monomer to obtain a polymer dispersed rubber composition in which the polymer is dispersed in the rubber in a solution phase, and removing the solvent to obtain a solid, wherein the polymer is polybutene, and has a weight average molecular weight of 300 to 20,000 g / mol, and 1 to 50 phr of the polymer is added per hundred parts of rubber solid content; and The step of mixing the solid matter of the polymer dispersed rubber composition with other rubbers to obtain the rubber composite material composition, wherein the other rubbers are polyolefin elastomers, including emulsion-polymerized styrene butadiene rubber, solution-polymerized styrene butadiene rubber, styrene-butadiene-styrene rubber, styrene-ethylene-butadiene-styrene rubber, butadiene rubber, butyl rubber or ethylene propylene rubber.

2. The method for preparing the rubber composite material composition according to claim 1, characterized in that: The monomer is one or more selected from the group consisting of styrene, butadiene, isobutylene, isoprene, ethylene, and propylene.

3. The method for preparing the rubber composite material composition according to any one of claims 1 to 2, characterized in that: The rubber composite composition is used as a rubber composition for tire treads, a rubber composition for shoe soles, a rubber composition for belts, a rubber composition for hoses, or a rubber composition for sheets.

4. The method for preparing the rubber composite material composition according to any one of claims 1 to 2, characterized in that: The rubber composite composition is used as a rubber composition for a sealant or a rubber composition for a hot melt adhesive.

5. A rubber composition for tire tread, characterized in that: The present invention comprises a rubber composite material composition prepared by the preparation method according to any one of claims 1 to 2.

6. A tire, characterized in that: The tire tread is manufactured using the rubber composition for a tire tread according to claim 5.

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