Pneumatic tire

Abstract

To provide a pneumatic tire which is excellent in crosslinking adhesion between a rubber member containing a hydrogenated copolymer and another rubber member while maintaining wear resistance of the hydrogenated copolymer.SOLUTION: The pneumatic tire comprises: a rubber member A containing a rubber component, sulfur, and a triazine thiol compound, the rubber component containing 70-100 mass% of a hydrogenated copolymer which is obtained by hydrogenating an aromatic vinyl-conjugated diene copolymer and has a weight average molecular weight measured by gel permeation chromatography of 300,000 or more and a hydrogenation rate of a conjugated diene moiety of 80 mol% or more; and a rubber member B containing a rubber component and sulfur, the rubber component containing a diene rubber. The rubber member A and the rubber member B are in contact with each other with an interface therebetween. The content of the triazine thiol compound is 0.1-5 pts.mass based on 100 pts.mass of the rubber component of the rubber member A.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a pneumatic tire.

Background Art

[0002] As a rubber material having high strength and excellent abrasion resistance, it is known to use a hydrogenated copolymer. However, since the double bonds of the hydrogenated copolymer are hydrogenated and there are few crosslinking points, the adhesiveness to other rubber members is poor, and there is a problem that defects such as peeling of members easily occur in the tire molding process.

[0003] As a method for improving adhesiveness, Patent Document 1 describes using a peroxide, and Patent Document 2 describes using a sulfenamide-based vulcanization accelerator having a specific structure. Patent Documents 3 and 4 describe rubber compositions containing a maleimide compound.

[0004] However, when the methods described in Patent Documents 1 to 4 are applied to a rubber composition containing a hydrogenated copolymer, it is necessary to adjust the vulcanization rate, and there is a problem that the abrasion resistance of the hydrogenated copolymer is impaired. As a method for improving crosslinking adhesiveness, it is also conceivable to increase the sulfur content in a rubber composition containing a hydrogenated copolymer, but there is a risk that the abrasion resistance may be impaired thereby.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] In view of the above points, the present invention aims to provide a pneumatic tire having excellent crosslinking adhesiveness between a rubber member containing a hydrogenated copolymer and a rubber member containing a diene rubber while maintaining the wear resistance of the hydrogenated copolymer.

Means for Solving the Problems

[0007] In order to solve the above problems, the pneumatic tire according to the present invention is a hydrogenated copolymer obtained by hydrogenating an aromatic vinyl-conjugated diene copolymer, having a weight average molecular weight measured by gel permeation chromatography of 300,000 or more, and a hydrogenation rate of the conjugated diene portion of 80 mol% or more. It has a rubber component containing 70 to 100% by mass of the hydrogenated copolymer, sulfur, a rubber member A containing a triazine thiol compound, and a rubber member B containing a rubber component containing a diene rubber and sulfur. The rubber member A and the rubber member B are in contact with each other with an interface, and the content of the triazine thiol compound is 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber member A.

[0008] The content of the diene rubber contained in the rubber component of the rubber member B can be 70 to 100% by mass.

[0009] The rubber member A further contains a quaternary ammonium salt, the content thereof is 0.1 part by mass or more with respect to 100 parts by mass of the rubber component of the rubber member A, and the content ratio of the quaternary ammonium salt to the triazine thiol compound (quaternary ammonium salt / triazine thiol compound) can be 0.1 to 2.0.

[0010] The triazine thiol compound can be 1,3,5-triazine-2,4,6-trithiol, and the quaternary ammonium salt can be tetrabutylammonium bromide.

Advantages of the Invention

[0011] According to the present invention, it is possible to obtain a pneumatic tire having excellent crosslinking adhesiveness between a rubber member containing a hydrogenated copolymer and a rubber member containing a diene rubber while maintaining the abrasion resistance of the hydrogenated copolymer.

Mode for Carrying Out the Invention

[0012] Hereinafter, matters related to the implementation of the present invention will be described in detail.

[0013] [Rubber member A] The rubber component of the rubber member A according to the present embodiment is a hydrogenated copolymer obtained by hydrogenating an aromatic vinyl-conjugated diene copolymer, and has a weight average molecular weight measured by gel permeation chromatography of 300,000 or more, and a hydrogenation rate of the conjugated diene portion of 80 mol% or more. Here, in this specification, the "weight average molecular weight measured by gel permeation chromatography (GPC)" means that a differential refractive index detector (RI) is used as a detector, tetrahydrofuran (THF) is used as a solvent, the measurement temperature is 40 ° C, the flow rate is 1.0 mL / min, the concentration is 1.0 g / L, and the injection volume is 40 μL, and the value calculated in terms of polystyrene using commercially available standard polystyrene. Further, the hydrogenation rate is a value calculated from the spectral reduction rate of the unsaturated bond portion of the spectrum obtained by measuring H 1 -NMR.

[0014] The aromatic vinyl constituting the aromatic vinyl-conjugated diene copolymer is not particularly limited, and examples thereof include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene and the like. These may be used alone or in combination of two or more.

[0015] The conjugated diene constituting the above aromatic vinyl-conjugated diene copolymer is not particularly limited, and examples thereof include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene and the like. These may be used alone or in combination of two or more.

[0016] The above aromatic vinyl-conjugated diene copolymer is not particularly limited, but is preferably a copolymer of styrene and 1,3-butadiene (styrene-butadiene copolymer). Therefore, the hydrogenated copolymer is preferably a hydrogenated styrene-butadiene copolymer. The hydrogenated copolymer may be a random copolymer, a block copolymer or an alternating copolymer.

[0017] The above hydrogenated copolymer can be synthesized, for example, by synthesizing an aromatic vinyl-conjugated diene copolymer and performing a hydrogenation treatment. The method for synthesizing the aromatic vinyl-conjugated diene copolymer is not particularly limited, and examples thereof include solution polymerization method, gas phase polymerization method, bulk polymerization method and the like, and the solution polymerization method is particularly preferred. The polymerization mode may be either batch type or continuous type. In addition, commercially available aromatic vinyl-conjugated diene copolymers can also be used.

[0018] The hydrogenation method is not particularly limited, and hydrogenation may be carried out by known methods under known conditions. Usually, it is carried out at 20 to 150 °C under a hydrogen pressure of 0.1 to 10 MPa in the presence of a hydrogenation catalyst. The hydrogenation rate can be arbitrarily selected by changing the amount of the hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, the reaction time, etc. As the hydrogenation catalyst, usually, a compound containing any of the metals of Groups 4 to 11 of the periodic table can be used. For example, compounds containing Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, Pt atoms can be used as the hydrogenation catalyst. More specific hydrogenation catalysts include metallocene compounds such as Ti, Zr, Hf, Co, Ni, Pd, Pt, Ru, Rh, Re, etc.; supported heterogeneous catalysts in which metals such as Pd, Ni, Pt, Rh, Ru, etc. are supported on carriers such as carbon, silica, alumina, diatomaceous earth, etc.; homogeneous Ziegler-type catalysts in which organic salts or acetylacetone salts of metal elements such as Ni, Co, etc. are combined with reducing agents such as organic aluminum; organometallic compounds or complexes such as Ru, Rh, etc.; and fullerenes or carbon nanotubes that have absorbed hydrogen, etc.

[0019] The hydrogenation rate of the hydrogenated copolymer (the ratio of hydrogen added to the conjugated diene part of the aromatic vinyl-conjugated diene copolymer) is 80 mol% or more, preferably 80 to 95 mol%, more preferably 85 to 95 mol%, and even more preferably 90 to 95 mol%. When the hydrogenation rate is 80 mol% or more, the effect of improving wear resistance due to the homogenization of crosslinking is excellent.

[0020] The weight average molecular weight of the hydrogenated copolymer is not particularly limited as long as it is 300,000 or more, but is preferably 300,000 to 2,000,000, more preferably 300,000 to 1,000,000, and even more preferably 300,000 to 600,000.

[0021] The rubber component of the rubber member A may contain a diene rubber other than the above hydrogenated copolymer. For example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, etc. may be mentioned. These diene rubbers can be used alone or in a blend of two or more.

[0022] The content ratio of the above hydrogenated copolymer in the rubber component is not particularly limited, but is preferably 70 to 100% by mass, and more preferably 80 to 100% by mass.

[0023] The above rubber member A contains a sulfur component such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, etc. as the above vulcanizing agent, and its content is not particularly limited, but it is preferably 0.5 to 4 parts by mass, and more preferably 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component in the rubber member A. When sulfur is contained within the above range, excellent crosslinking adhesiveness between the rubber member A and the rubber member B is likely to be obtained.

[0024] The above rubber member A contains a triazine thiol compound, and the content thereof is 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component in the rubber member A. When the content of the triazine thiol compound is within the above range, excellent abrasion resistance and crosslinking adhesiveness are easily obtained. As the triazine thiol compound, it is only necessary to have two or more thiol groups in the triazine. Examples of such compounds include 1,3,5-triazine-2,4,6-trithiol, 2-(dibutylamino)-1,3,5-triazine-4,6-dithiol, 6-diallylamino-1,3,5-triazine-2,4-dithiol, 2-amino-4-methoxy-6-(trifluoromethyl)-1,3,5-triazine, 6-(4-vinylbenzyl-n-propyl)amino-1,3,5-triazine-2,4-dithiol, 6-(diisopropylamino)-1,3,5-triazine-2,4-dithiol, 6-(diisobutylamino)-1,3,5-triazine-2,4-dithiol, 6-di(2-ethylhexyl)amino-1,3,5-triazine-2,4-dithiol, 6-(allylamino)-1,3,5-triazine-2,4-dithiol, 6-(butylamino)-1,3,5-triazine-2,4-dithiol, etc. Among these, 1,3,5-triazine-2,4,6-trithiol is preferable.

[0025] The above rubber member A may further contain a quaternary ammonium salt. The quaternary ammonium salt is not particularly limited. Examples thereof include tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium iodide, benzyltriethylammonium chloride, benzalkonium chloride, didodecyldimethylammonium bromide, dimethylditetradecylammonium bromide, trimethyl-n-octylammonium bromide, tetramethylammonium chloride, trimethyltetradecylammonium chloride, benzyltrimethylammonium dichloroiodate, dodecyltrimethylammonium bromide, tetramethylammonium iodide, etc. Among these, tetrabutylammonium bromide is preferable.

[0026] When containing a quaternary ammonium salt, its content is preferably 0.1 part by mass or more with respect to 100 parts by mass of the rubber component in the rubber member A. Further, the content ratio of the quaternary ammonium salt to the triazine thiol compound (quaternary ammonium salt / triazine thiol compound) is not particularly limited, but is preferably 0.1 to 2.0. When the quaternary ammonium salt is contained within the above range, excellent abrasion resistance and crosslinking adhesiveness are easily obtained.

[0027] [Rubber member B] The rubber component used in the rubber member B according to the present embodiment contains a diene rubber, and the content ratio of the diene rubber in the rubber component is not particularly limited, but is preferably 70 to 100% by mass, and more preferably 80 to 100% by mass.

[0028] Examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, and the like. These diene rubbers can be used alone or in a blend of two or more.

[0029] The rubber member B contains a sulfur component such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, etc. as a vulcanizing agent, and its content is not particularly limited, but is preferably 0.5 to 4 parts by mass, and more preferably 1 to 3.5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber member B. When sulfur is contained within the above range, excellent crosslinking adhesiveness between the rubber member A and the rubber member B is easily obtained.

[0030] The pneumatic tire according to this embodiment has a rubber member A and a rubber member B in contact with each other with an interface therebetween. By containing sulfur and a triazine thiol compound in a predetermined content in the rubber member A, excellent crosslinking adhesiveness can be obtained. Although the mechanism is not clear, it can be speculated as follows. Since the hydrogenated copolymer has a small amount of double bonds, when laminated with other rubber members, the number of crosslinking points via sulfur at the interface decreases. However, as a crosslinking structure other than sulfur crosslinking, by using the triazine thiol compound as a crosslinking point, it can be speculated that excellent crosslinking adhesiveness can be obtained at the interface between the rubber member A and the rubber member B.

[0031] [Other compounding chemicals] In addition to the above-described components, the rubber member A and the rubber member B according to this embodiment may be appropriately compounded within a normal range with compounding chemicals such as reinforcing fillers, processing aids, zinc white, stearic acid, softeners, plasticizers, liquid rubbers, resins, waxes, anti-aging agents, and vulcanization accelerators, which are used in the normal rubber industry. The compounding of the compounding chemicals may be different between the rubber member A and the rubber member B.

[0032] Examples of the reinforcing filler include silica and carbon black, and those using silica and carbon black in combination may also be used. That is, the reinforcing filler may be silica alone, carbon black alone, or a combination of silica and carbon black. Preferably, it is a combination of silica and carbon black. The content of the reinforcing filler is not particularly limited, and is preferably 10 to 150 parts by mass, more preferably 20 to 100 parts by mass, and even more preferably 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component.

[0033] Although silica is not particularly limited, wet silica such as wet precipitation method silica and wet gel method silica is preferably used. The content of silica is 1 to 150 parts by mass, preferably 1 to 100 parts by mass with respect to 100 parts by mass of the rubber component.

[0034] Further, it may further contain a silane coupling agent such as sulfide silane or mercapto silane. When containing a silane coupling agent, its content is preferably 2 to 20% by mass with respect to the silica content.

[0035] The carbon black is not particularly limited, and various known varieties can be used. The content of the carbon black is preferably 1 to 70 parts by mass, more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the rubber component.

[0036] As the vulcanization accelerator, sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, thiuram-based vulcanization accelerators, thiazole-based vulcanization accelerators, thiourea-based vulcanization accelerators, etc. can be used. Among these, sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, and dithiocarbamate-based vulcanization accelerators are preferred.

[0037] Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazolyl sulfenamide (CZ), N-tert-butyl-2-benzothiazolyl sulfenamide (NS), N-oxydiethylene-2-benzothiazolyl sulfenamide (MBS), and N,N-diisopropyl-2-benzothiazole sulfenamide (DZ).

[0038] Examples of the guanidine-based vulcanization accelerator include 1,3-diphenylguanidine (D), di-O-tolylguanidine (DT), etc.

[0039] Examples of dithiocarbamate vulcanization accelerators include zinc dibenzyldithiocarbamate (ZnBzDTC), zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC), zinc di-n-butyldithiocarbamate (ZnBDC), zinc N-pentamethylenedithiocarbamate (ZnPDC), zinc ethylphenyldithiocarbamate (ZnEPDC), sodium dimethyldithiocarbamate (NaMDC), sodium diethyldithiocarbamate (NaEDC), sodium di-n-butyldithiocarbamate (NaBDC), tellurium diethyldithiocarbamate (TeEDC), copper dimethyldithiocarbamate (CuMDC), iron dimethyldithiocarbamate (FeMDC), and the like.

[0040] When a sulfenamide vulcanization accelerator is contained, its content is not particularly limited, but it is preferably 0.1 to 3 parts by mass, more preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the rubber component.

[0041] When a guanidine vulcanization accelerator is contained, its content is not particularly limited, but it is preferably 0.1 to 3 parts by mass, more preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the rubber component.

[0042] When a dithiocarbamate vulcanization accelerator is contained, its content is not particularly limited, but it is preferably 0.1 to 3 parts by mass, more preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the rubber component.

[0043] In rubber member A, it is preferable to use a dithiocarbamate vulcanization accelerator and a guanidine vulcanization accelerator in combination, and the mixing ratio (guanidine vulcanization accelerator / dithiocarbamate vulcanization accelerator) is preferably 0.5 to 3.0 in terms of mass ratio.

[0044] The total content of the vulcanization accelerator in each rubber member is preferably 0.1 to 9 parts by mass, more preferably 0.5 to 6 parts by mass, based on 100 parts by mass of the rubber component.

[0045] The rubber composition according to the present embodiment can be produced by kneading in accordance with a conventional method using a mixer such as a commonly used Banbury mixer, kneader, roll, etc. That is, in the first mixing stage, additives other than the vulcanizing agent and the vulcanization accelerator are added and mixed to the rubber component, and then the vulcanizing agent and the vulcanization accelerator are added and mixed to the obtained mixture in the final mixing stage to prepare a rubber composition.

[0046] The rubber composition thus obtained can be used for tires and can be applied to each part of a pneumatic tire such as the tread part and the sidewall part of pneumatic tires of various applications and sizes such as passenger car tires, large tires for trucks and buses. The rubber composition is formed into rubber member A and rubber member B having a predetermined shape by extrusion processing, for example, in accordance with a conventional method, and after being combined with other parts, a pneumatic tire can be manufactured by vulcanization molding at 140 to 180 °C, for example.

[0047] If the rubber member A and the rubber member B are in contact with each other with an interface, the application site is not particularly limited. For example, in a tread part having a base rubber disposed on the outer side in the tire radial direction of the belt layer and a cap rubber disposed on the outer side in the tire radial direction of the base rubber, rubber member A may be used as the cap rubber and rubber member B may be used as the base rubber. In a tread part where different rubber members are arranged in the width direction, the inside (the inside of the vehicle when the tire is mounted) may be rubber member A and the outside (the outside of the vehicle when the tire is mounted) may be rubber member B, or the outside may be rubber member A and the inside may be rubber member B. Further, the application site of rubber member A may be the tread part, and the application site of rubber member B may be the shoulder part, the side part, or the belt layer.

[0048] The types of pneumatic tires according to this embodiment are not particularly limited, and various tires such as passenger car tires and heavy-duty tires used for trucks and buses can be mentioned.

Example

[0049] Examples of the present invention are shown below, but the present invention is not limited to these examples.

[0050] 〈Synthesis Example of Hydrogenated Copolymer 1〉 Into a heat-resistant reaction vessel purged with nitrogen, 2.5 L of cyclohexane, 50 g of tetrahydrofuran (THF), 0.12 g of n-butyllithium, 100 g of styrene, and 400 g of 1,3-butadiene were placed, and polymerization was carried out at a reaction temperature of 50°C. After the polymerization was completed, 1.7 g of N,N-bis(trimethylsilyl)aminopropylmethyldiethoxylane was added and reacted for 1 hour. Then, hydrogen gas was supplied at a pressure of 0.4 MPa-gauge and stirred for 20 minutes. Next, the hydrogen gas supply pressure was set to 0.7 MPa-gauge and the reaction temperature was set to 90°C, and the reaction was carried out using a catalyst mainly composed of titanocene dichloride until the desired hydrogenation rate was reached. By removing the solvent, hydrogenated copolymer 1 was obtained.

[0051] The weight-average molecular weight of the obtained hydrogenated copolymer 1 was measured using "LC-10A" manufactured by Shimadzu Corporation as a measuring device, "PLgel-MIXED-C" manufactured by Polymer Laboratories as a column, a differential refractive index detector (RI) as a detector, THF as a solvent, a measurement temperature of 40°C, a flow rate of 1.0 mL / min, a concentration of 1.0 g / L, and an injection volume of 40 μL. The measurement was carried out in terms of polystyrene conversion using standard polystyrene and was 350,000. The amount of bound styrene was 20% by mass, and the hydrogenation rate of the butadiene part was 90 mol%. The amount of bound styrene was determined from the spectral intensity ratio of protons based on styrene units and protons based on butadiene units (including the hydrogenated part) using H 1 -NMR.

[0052] 〈Examples and Comparative Examples〉 Using a Banbury mixer, according to the formulations A and B (parts by mass) shown in Tables 1 and 2 below, first, in the first mixing stage (non-pro kneading process), the components excluding the vulcanization accelerator, sulfur, and the triazine thiol compound were added and mixed (discharge temperature = 160 °C). Then, to the obtained mixture, in the final mixing stage (pro kneading process), the vulcanization accelerator, sulfur, and the triazine thiol compound were added and mixed (discharge temperature = 90 °C) to prepare a rubber composition.

[0053] Details of each component in Table 1 are as follows. · Hydrogenated SBR1: Hydrogenated copolymer 1 prepared according to Synthesis Example 1 above · Silica: "Ultrasil VN3" manufactured by Evonik Japan · Silane coupling agent: "Si69" manufactured by Evonik Japan · Carbon black: "Seast 3" manufactured by Tokai Carbon Co., Ltd. · Aromatic oil: "Process NC140" manufactured by JXTG Energy Corporation · Zinc oxide: "Zinc Oxide Type 2" manufactured by Mitsui Mining & Smelting Co., Ltd. · Antioxidant: "Antigen 6C" manufactured by Sumitomo Chemical Co., Ltd. · Stearic acid: "Lunac S-20" manufactured by Kao Corporation · Wax: "OZOACE0355" manufactured by Nippon Seiro Co., Ltd. · Quaternary ammonium salt: "Tetrabutylammonium bromide" manufactured by Tokyo Chemical Industry Co., Ltd. · Vulcanization accelerator 1: "Soxinol CZ" manufactured by Sumitomo Chemical Co., Ltd., a sulfenamide-based vulcanization accelerator · Vulcanization accelerator 2: "Nocceler-D" manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., a guanidine-based vulcanization accelerator · Vulcanization accelerator 3: "Sanseler ZBE" manufactured by Sanshin Chemical Industry Co., Ltd., a dithiocarbamate-based vulcanization accelerator · Sulfur: "Micro Powder Sulfur" manufactured by Tsurumi Chemical Industry Co., Ltd. · Triazine thiol compound: "1,3,5-Triazine-2,4,6-trithiol" manufactured by Tokyo Chemical Industry Co., Ltd.

[0054] Details of each component in Table 2 are as follows. ·ESBR: "SBR1502" manufactured by JSR Corporation, emulsion-polymerized styrene-butadiene rubber, weight-average molecular weight = 420,000 · Modified SSBR: "HPR350" manufactured by JSR Corporation, styrene content 21% by mass, alkoxyl group and amino group-terminated modified solution-polymerized SBR · Silica: "Ultrasil VN3" manufactured by Evonik Japan · Silane coupling agent: "Si69" manufactured by Evonik Japan · Carbon black: "Seast 3" manufactured by Tokai Carbon Co., Ltd. · Aromatic oil: "Process NC140" manufactured by JXTG Energy Corporation · Zinc oxide: "Zinc Oxide Type 2" manufactured by Mitsui Mining & Smelting Co., Ltd. · Antioxidant: "Antigen 6C" manufactured by Sumitomo Chemical Co., Ltd. · Stearic acid: "Lunac S-20" manufactured by Kao Corporation · Wax: "OZOACE0355" manufactured by Nippon Seiro Co., Ltd. · Resin: C5 / C9-based petroleum resin, "Petrotack 90" manufactured by Tosoh Corporation · Vulcanization accelerator 1: "Soxinol CZ" manufactured by Sumitomo Chemical Co., Ltd., sulfenamide-based vulcanization accelerator · Vulcanization accelerator 2: "Nocceler-D" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., guanidine-based vulcanization accelerator · Sulfur: "Fine Powder Sulfur" manufactured by Tsurumi Chemical Industry Co., Ltd., specific gravity = 2

[0055]

Table 1

[0056]

Table 2

[0057] The abrasion resistance of the obtained rubber composition of formulation A was evaluated. Furthermore, the crosslinking adhesiveness was evaluated using test pieces obtained by adhering the rubber composition of formulation A and the rubber composition of formulation B and vulcanizing at 160 °C for 30 minutes. The measurement and evaluation methods are as follows, and the evaluation results are shown in Table 1.

[0058] · Abrasion resistance: In accordance with JIS K6264, using a Lambourn abrasion tester manufactured by Iwamoto Seisakusho Co., Ltd., the abrasion loss was measured under the conditions of a load of 40 N and a slip rate of 30%. For the reciprocal of the measured value, it was expressed as an index with the value of Comparative Example 1 being 100. The larger the index, the less the abrasion loss, which means better abrasion resistance.

[0059] · Crosslinking adhesiveness: The rubber sample A of formulation A and the rubber sample B of formulation B made into strips were overlapped, a PET film was sandwiched in part, and vulcanized at 160 °C for 30 minutes to bond the rubber sample A and the rubber sample B. After vulcanization, the unbonded part of the rubber sample A and the rubber sample B was gripped by "Autograph DCS500" manufactured by Shimadzu Corporation, and peeled at a peeling speed of 50 mm / min so that the bonded rubber sample became T-shaped. After peeling, when the peeled cross-section was rubber failure, it was evaluated as "○", assuming that the rubber sample A and the rubber sample B had excellent crosslinking adhesiveness, and when it was interfacial peeling, it was evaluated as "×", assuming that the crosslinking adhesiveness of the rubber sample A and the rubber sample B was inferior.

[0060] The results are as shown in Table 1. Examples 1 to 7 were superior in abrasion resistance and crosslinking adhesiveness compared with Comparative Example 1.

[0061] Comparative Example 2 was an example where the content of the triazine thiol compound exceeded the upper limit value, and the crosslinking adhesiveness was inferior.

Industrial applicability

[0062] The pneumatic tire of the present invention can be used as various tires such as passenger cars, light trucks, and buses.

Claims

1. A hydrogenated copolymer obtained by hydrogenating an aromatic vinyl-conjugated diene copolymer, having a weight average molecular weight of 300,000 or more measured by gel permeation chromatography, and a hydrogenation rate of the conjugated diene portion of 80 mol% or more, a rubber component containing 70 to 100% by mass of the hydrogenated copolymer, sulfur, and a rubber member A containing a triazine thiol compound, a rubber member B containing a rubber component containing a diene-based rubber and sulfur, wherein the rubber member A and the rubber member B are in contact with each other with an interface, and the content of the triazine thiol compound is 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber member A, a pneumatic tire.

2. The pneumatic tire according to claim 1, wherein the content of the diene-based rubber contained in the rubber component of the rubber member B is 70 to 100% by mass.

3. The rubber member A further contains a quaternary ammonium salt, and the content thereof is 0.1 part by mass or more with respect to 100 parts by mass of the rubber component of the rubber member A, and the content ratio of the quaternary ammonium salt to the triazine thiol compound (quaternary ammonium salt / triazine thiol compound) is 0.1 to 2.0, the pneumatic tire according to claim 1 or 2.

4. The triazine thiol compound is 1,3,5-triazine-2,4,6-trithiol, and the quaternary ammonium salt is tetrabutylammonium bromide, the pneumatic tire according to claim 3.

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