Rubber composition, tread and tire

Abstract

To provide a tire rubber composition that can be produced with excellent workability and has an excellent wet grip performance and rolling performance, and to provide a tread and a tire.SOLUTION: A tire rubber composition comprises a rubber component comprising isoprene rubber, a liquid polymer with an SP value of 7.95-8.45 (cal / cm3)1 / 2 and kinematic viscosity of 40,000 mm2 / s or less as measured at 40°C in accordance with JISK2283, a resin with an SP value of 8.0-9.6 (cal / cm3)1 / 2, and a filler.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a rubber composition, a tread, and a tire.

Background Art

[0002] From the viewpoint of improving vehicle safety, various studies have been made to improve the braking performance and driving performance of tires not only on dry road surfaces but also on various road surfaces such as wet road surfaces, ice and snow road surfaces. For example, in order to improve the braking performance on dry and wet road surfaces, for 100 parts by mass of a rubber component containing 70% by mass or more of natural rubber, C 5 -based resin, C 5 -C 9 -based resin, C 9 -based resin, terpene-based resin, terpene-aromatic compound-based resin, rosin-based resin, dicyclopentadiene resin, and at least one thermoplastic resin selected from alkylphenol-based resins in an amount of 5 to 50 parts by mass, and a filler containing silica in an amount of 20 to 120 parts by mass are disclosed (Patent Document 1). In addition, in order to improve wet grip performance, a vulcanized unvulcanized rubber composition containing a rubber component containing a diene polymer, having a continuous phase and one or more discontinuous phases, and a filler and an on-liquid polymer are localized in the continuous phase. A rubber composition for a tread is disclosed (Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the rubber composition of Patent Document 1 attempts to improve the wet grip performance on a wet road surface or the like, the rolling resistance deteriorates and the fuel consumption of the vehicle tends to decrease, and an improvement in the balance between the wet grip performance and the rolling resistance has been demanded. In addition, the tread rubber composition of Patent Document 2 has a problem in that the workability of the liquid polymer during the production of the rubber composition is low and the productivity is lacking. In view of the above circumstances, an object of the present invention is to provide a rubber composition for tires, a tread, and a tire that are excellent in workability during the production of the rubber composition and excellent in wet grip performance and rolling performance.

Means for Solving the Problems

[0005] <1>A rubber composition containing an isoprene-based rubber, a liquid polymer having an SP value of 7.95 to 8.45 (cal / cm 3 ) 1 / 2 and a kinematic viscosity measured by JIS K2283 at 40°C of 40,000 mm 2 / s or less, and a resin having an SP value of 8.0 to 9.6 (cal / cm 3 ) 1 / 2 and a filler, a rubber composition for tires.

[0006] <2>The rubber composition for tires according to <1>, wherein the resin contains more than 65% by mass of a structural unit having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton as a component constituting the resin.

[0007] <3>The rubber composition for tires according to <1> or <2>, wherein the resin contains at least one selected from C 5 -based resins, hydrogenated C 5 -based resins, C 5 -C 9 -based resins, hydrogenated C 5 -C 9 -based resins, cyclopentene resins, cyclopentadiene resins, dicyclopentene resins, dicyclopentadiene resins, and terpene resins.

[0008] <4>The rubber composition for a tire according to any one of <1> to <3>, wherein the liquid polymer contains, as components constituting the liquid polymer, constitutional units having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton in a mass ratio of more than 80%.

[0009] <5>The rubber composition for a tire according to any one of <1> to <4>, wherein the liquid polymer is composed of constitutional units having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton.

[0010] <6>The rubber composition for a tire according to any one of <1> to <5>, wherein the mass ratio (liquid polymer / resin) of the liquid polymer to the resin is 0.5 to 5.

[0011] <7>The rubber composition for a tire according to any one of <1> to <6>, wherein the content of the isoprene-based rubber in the rubber component is 5 to 100% by mass.

[0012] <8>The rubber composition for a tire according to any one of <1> to <7>, wherein the filler contains silica and carbon black.

[0013] <9>The rubber composition for a tire according to any one of <1> to <8>, wherein the content of the filler is 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component.

[0014] <10>A tread member using the rubber composition for a tire according to any one of <1> to <9>.

[0015] <11>A tire using the tread member according to <10>.

Advantages of the Invention

[0016] According to the present invention, it is possible to provide a rubber composition for a tire, a tread, and a tire, which are excellent in workability during the production of the rubber composition and excellent in wet grip performance and rolling performance.

Embodiments for Carrying Out the Invention

[0017] [Rubber Composition for a Tire] The rubber composition for tires of the present invention comprises a rubber component containing an isoprene-based rubber, a liquid polymer having an SP value of 7.95 to 8.45 (cal / cm 3 ) 1 / 2 and having a kinematic viscosity measured by JIS K2283 at 40°C of 40,000 mm 2 / s or less, a resin having an SP value of 8.0 to 9.6 (cal / cm 3 ) 1 / 2 and a filler, and is a rubber composition for tires.

[0018] By using in combination the liquid polymer having an SP value of 7.95 to 8.45 (cal / cm 3 ) 1 / 2 and having a kinematic viscosity measured by JIS K2283 at 40°C of 40,000 mm 2 / s or less and the resin having an SP value of 8.0 to 9.6 (cal / cm 3 ) 1 / 2 in the rubber composition for tires, it is possible to improve the rolling resistance performance to be equal to or better than the original while further improving the wet grip performance. This is because when the resin having the above-mentioned SP value is blended in the rubber composition for tires, by using the liquid polymer having the above-mentioned SP value, the liquid polymer can effectively dissolve the resin, so it is possible to prevent the occurrence of unnecessary losses leading to the deterioration of the rolling resistance due to the incompatible components of the resin, and it is considered that the rolling resistance performance and the wet grip performance can be improved in a well-balanced manner. In addition, since the kinematic viscosity of the liquid polymer measured by JIS K2283 at 40°C is 40,000 mm 2 / s or less, the workability in manufacturing the rubber composition for tires can be improved, and the tires using the rubber composition for tires of the present invention have improved handling stability.

[0019] In the present invention, the SP value (solubility parameter) is calculated by the Fedors method. Also, in the present invention, the viscosity of the liquid polymer at 40°C is measured at 40°C in accordance with JIS K2283.

[0020] <Rubber component> The rubber composition for tires of the present invention contains at least an isoprene rubber as a rubber component. By containing an isoprene rubber, the mechanical strength of the rubber composition for tires can be increased, so that the abrasion resistance, tear strength, etc. are high, and the rolling resistance performance of the tire is excellent. Examples of the isoprene rubber include natural rubber (NR), polyisoprene rubber (IR), butadiene-isoprene copolymer rubber (BIR), styrene-isoprene copolymer rubber (SIR), styrene-butadiene-isoprene copolymer rubber (SBIR), etc., and modified rubbers thereof. Only one kind of isoprene rubber may be used, or two or more kinds may be mixed and used. Among these, from the viewpoint of improving the rolling resistance performance of the tire, one or more kinds selected from natural rubber and polyisoprene rubber are preferable as the isoprene rubber, and natural rubber is more preferable.

[0021] As the rubber component, it is preferable that other diene rubbers such as styrene-butadiene rubber (SBR) and butadiene rubber (BR) and modified rubbers thereof are further included, and it is preferable that styrene-butadiene rubber is included. By further including other diene rubbers and modified rubbers thereof, the wet grip performance and rolling resistance performance of the rubber composition for tires can be easily improved.

[0022] In the present invention, the content of the isoprene rubber in the rubber component is preferably 5 to 100% by mass, more preferably 15 to 80% by mass, and still more preferably 25 to 60% by mass. When the content of the isoprene rubber in the rubber component is within the above range, the wet grip performance and rolling resistance performance of the rubber composition for tires can be easily improved in a well-balanced manner.

[0023] <Liquid polymer> The rubber composition for tires of the present invention has an SP value of 7.95 to 8.45 (cal / cm 3 ) 1 / 2 and the kinematic viscosity measured by JIS K2283 at 40°C is 40,000 mm2 It contains a liquid polymer with a kinematic viscosity of 1 / s or less.

[0024] In the present invention, when the SP value of the liquid polymer is 7.95 to 8.45 (cal / cm 3 ), 1 / 2 it is possible to efficiently dissolve the resin described later, so that the generation of unnecessary losses leading to the deterioration of rolling resistance due to the incompatible components of the resin can be suppressed, and the rolling resistance performance and the wet grip performance can be improved in a well-balanced manner. From the viewpoint of efficiently dissolving the resin and improving the rolling resistance performance and the wet grip performance in a well-balanced manner, the SP value of the liquid polymer is 7.95 to 8.45 (cal / cm 3 ). 1 / 2 is preferable, 7.95 to 8.35 (cal / cm 3 ) 1 / 2 is more preferable, and 7.95 to 8.15 (cal / cm 3 ) 1 / 2 is even more preferable.

[0025] In the present invention, when the kinematic viscosity of the liquid polymer at 40 ° C is 40,000 mm 2 / s or less, the workability during the production of the rubber composition for tires can be sufficiently ensured. When the kinematic viscosity of the liquid polymer at 40 ° C exceeds 40,000 mm 2 / s, the workability cannot be ensured, and the production efficiency tends to decrease significantly. From the viewpoint of improving the workability during the production of the rubber composition for tires, the kinematic viscosity of the liquid polymer at 40 ° C is preferably 39,000 mm 2 / s or less, and more preferably 38,000 mm 2 / s or less. Also, in the present invention, as the lower limit of the kinematic viscosity of the liquid polymer at 40 ° C, 20,000 mm 2 / s or more is preferable, 30,000 mm 2 / s or more is more preferable, and 35,000 mm 2 / s or more is even more preferable. When the kinematic viscosity of the liquid polymer at 40 ° C is 20,000 mm 2By being at / s or more, the liquid polymer can easily bleed out to the rubber surface and can easily prevent stickiness of the rubber and the like.

[0026] As the liquid polymer, as a component constituting the liquid polymer, it is preferable to contain more than 80% by mass, more preferably 90% by mass or more, and even more preferably 100% by mass, that is, consisting of a structural unit having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton in terms of mass ratio. By the liquid polymer containing a structural unit having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton, it becomes easy to satisfy the SP value of the liquid polymer and the kinematic viscosity at 40 °C within the above range, and it is easy to improve the wet grip performance and rolling resistance performance of the rubber composition for tires in a well-balanced manner.

[0027] As the liquid polymer as described above, for example, one or more selected from liquid ethylene-α-olefin oligomers, liquid polybutadiene, liquid butadiene-styrene copolymers, etc. are preferable, and liquid ethylene-α-olefin oligomers are more preferable. As the liquid ethylene-α-olefin oligomer, a liquid ethylene-propylene oligomer is even more preferable. As the liquid polymer, commercially available products may be used. For example, Lucant LX400 (kinematic viscosity at 40 °C: 37,500 mm 2 / s, manufactured by Mitsui Chemicals, Inc.) and the like can be mentioned.

[0028] In the rubber composition for tires of the present invention, the content of the liquid polymer is preferably 3 to 25 parts by mass, more preferably 5 to 20 parts by mass, and even more preferably 8 to 15 parts by mass with respect to 100 parts by mass of the rubber component. Since the content of the liquid polymer is 3 parts by mass or more, the resin can be efficiently compatibilized by the liquid polymer, so that the wet grip performance and the rolling resistance performance can be easily improved in a well-balanced manner. Further, since the content of the liquid polymer is 25 parts by mass or less, the workability during the production of the rubber composition for tires can be easily improved, and the decrease in the rubber elastic modulus when the tire is formed can be suppressed, and it is easy to suppress the decrease in the braking performance.

[0029] <resin> The rubber composition for tires of the present invention contains a resin having an SP value of 8.0 to 9.6 (cal / cm 3 ) 1 / 2 . By blending the resin into the rubber composition for tires, the glass transition temperature can be increased, so that the tangent loss at 0°C (0°C tanδ) is improved and the wet grip performance can be improved. In particular, since the SP value of the resin is 8.0 to 9.6 (cal / cm 3 ) 1 / 2 , the compatibility with the rubber component is improved, and further compatibility is improved by the above liquid polymer, so that the wet grip performance can be more effectively improved. The SP value of the resin is preferably 8.0 to 9.6 (cal / cm 3 ) 1 / 2 from the viewpoint of more easily improving the wet grip performance, more preferably 8.1 to 9.6 (cal / cm 3 ) 1 / 2 , and even more preferably 8.15 to 9.6 (cal / cm 3 ) 1 / 2 .

[0030] In the present invention, the resin preferably contains more than 65% by mass, more preferably 75% by mass or more, and even more preferably 85% by mass or more of a structural unit having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton as a component constituting the resin. By containing more than 65% by mass of a structural unit having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton in the resin, it becomes easier for the SP value of the resin to satisfy the above range, and it becomes easier to improve the wet grip performance and the rolling resistance performance of the rubber composition for tires in a well-balanced manner. In addition, the content of the above-mentioned "structural unit having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton" can be analyzed, for example, by gas chromatography (GC) using a hydrogen ionization detector (FID) as a detector after thermally decomposing the resin with a thermal decomposition device or the like.

[0031] Further, in the present invention, as the resin as described above, C 5 -based resin, hydrogenated C 5 -based resin, C 5 -C 9 -based resin, hydrogenated C 5 -C 9 -based resin, cyclopentene resin, cyclopentadiene resin, dicyclopentene resin, dicyclopentadiene resin, and terpene resin are preferably included, and C 5 -based resin, hydrogenated C 5 -based resin, C 5 -C 9 -based resin, and hydrogenated C 5 -C 9 -based resin are more preferably included, and C 5 -based resin is even more preferably included.

[0032] In the present invention, the C 5 -based resin refers to a C 5 -based synthetic petroleum resin. For example, using a Friedel-Crafts type catalyst such as AlCl 3 or BF 3 , it refers to a solid polymer obtained by polymerizing a C 5 fraction. Specifically, copolymers mainly composed of isoprene, cyclopentadiene, 1,3-pentadiene, 1-pentene, etc., copolymers of 2-pentene and dicyclopentadiene, polymers mainly composed of 1,3-pentadiene, etc. are exemplified. Further, the "hydrogenated C 5 -based resin" refers to a resin obtained by reducing and hydrogenating the above-mentioned C 5 -based resin. Furthermore, if a C 5 -based resin is used as the resin, it is easier to further improve the wet grip performance.

[0033] In the present invention, the C 5 -C 9 -based resin refers to a C 5 -C 9 -based synthetic petroleum resin. For example, using Friedel-Crafts type catalysts such as AlCl 3 or BF 3 , polymerizing the C 5 -C 11 fraction to obtain a solid polymer. The C 5 -C 9 -based resin includes, for example, copolymers mainly composed of styrene, vinyltoluene, α-methylstyrene, indene, etc. In the present invention, this C 5 -C 9 -based resin with less of the above components is preferable from the viewpoint of compatibility with the rubber component. Here, having less of the above components means that the above components in the total amount of the resin are less than 50% by mass, preferably 40% by mass or less. Also, "hydrogenated C 9 -C 9 -based resin" refers to a resin obtained by reducing and hydrogenating the above C 9 -C 5 -C 9 -based resin. 5 -C 9 In addition, if a C 5 -C 9 -based resin is used as the resin, it is easier to further improve the workability. Here, the C 5 -C 9 -based polymer used for the polymerization of the resin as the C 5 -C 11 fraction includes fractions other than the C 5 fraction and the C 9 fraction.

[0034] In the present invention, dicyclopentadiene resin, for example, AlCl 3 or BF 3It refers to a resin obtained by polymerizing dicyclopentadiene using a Friedel-Crafts type catalyst such as the like. Specific examples of commercially available dicyclopentadiene resins include Quintone 1920 (manufactured by Nippon Zeon Co., Ltd.), Quintone 1105 (manufactured by Nippon Zeon Co., Ltd.), Marcares M-890A (manufactured by Maruzen Petrochemical Co., Ltd.), and the like. In addition, if a C 5 -based resin is used, the wet grip performance can be more easily improved.

[0035] In the present invention, the terpene resin is a solid resin obtained by blending turpentine oil obtained simultaneously when rosin is obtained from pine trees or a polymerized component separated therefrom, and polymerizing using a Friedel-Crafts type catalyst, and includes β-pinene resin, α-pinene resin, and the like. Further, as the terpene-aromatic compound-based resin, a terpene-phenol resin can be cited as a representative example. This terpene-phenol resin can be obtained by reacting terpenes and various phenols using a Friedel-Crafts type catalyst or by further condensing with formalin. The terpenes as raw materials are not particularly limited, and monoterpene hydrocarbons such as α-pinene and limonene are preferable, those containing α-pinene are more preferable, and α-pinene is particularly preferable. In the present invention, a terpene-phenol resin with a low ratio of the phenol component is suitable. Here, "a low ratio of the phenol component" means that the phenol component in the total amount of the resin is less than 50% by mass, preferably 40% by mass or less. In addition, if a terpene-aromatic compound-based resin, particularly a terpene-phenol resin, is used as the resin, the workability can be more easily improved.

[0036] In the rubber composition for tires of the present invention, the content of the resin is preferably 3 to 25 parts by mass, more preferably 5 to 20 parts by mass, and still more preferably 8 to 15 parts by mass with respect to 100 parts by mass of the rubber component. Since the resin content is 3 parts by mass or more, the resin can be efficiently dissolved by the liquid polymer, so that the wet grip performance and the rolling resistance performance can be easily improved in a well-balanced manner. Further, since the content of the liquid polymer is 25 parts by mass or less, the content of the rubber component in the rubber composition for tires can be ensured, so that the mechanical strength can be increased, and thus the abrasion resistance, tear strength, etc. can be easily improved.

[0037] In the present invention, the mass ratio (liquid polymer / resin) of the liquid polymer to the resin is preferably 0.5 to 5, more preferably 0.6 to 2.5, and still more preferably 0.7 to 1.7. Since the mass ratio (liquid polymer / resin) is 0.5 or more, the resin can be efficiently dissolved by the liquid polymer, so that the wet grip performance and the rolling resistance performance can be easily improved in a well-balanced manner. Further, since the mass ratio (liquid polymer / resin) is 5 or less, the workability during the production of the rubber composition for tires can be easily improved, and the decrease in the rubber elastic modulus when the tire is formed can be suppressed, and it is easy to suppress the decrease in the braking performance.

[0038] In the present invention, the absolute value of the difference in SP value between the liquid polymer and the resin (|[SP value of liquid polymer] - [SP value of resin]|) is preferably 2.0 (cal / cm 3 ) 1 / 2 or less, more preferably 1.5 (cal / cm 3 ) 1 / 2 or less, and still more preferably 0.5 (cal / cm 3 ) 1 / 2 or less. Since the absolute value of the difference in SP value (|[SP value of liquid polymer] - [SP value of resin]|) is 1.5 (cal / cm 3 ) 1 / 2 or less, the resin can be efficiently dissolved by the liquid polymer, so that the wet grip performance and the rolling resistance performance can be easily improved in a well-balanced manner.

[0039] <Filler> The rubber composition for tires of the present invention contains a filler. When the rubber composition for tires contains a filler, a reinforcing effect can be achieved without impairing the flexibility of the rubber composition for tires.

[0040] In the rubber composition for tires of the present invention, the filler is not particularly limited. For example, it preferably contains at least one selected from silica, clay, talc, calcium carbonate, aluminum hydroxide, and carbon black, more preferably contains at least one selected from silica and carbon black, and still more preferably contains silica and carbon black.

[0041] (Silica) In the present invention, by blending silica as a filler, the mechanical strength of the rubber composition for tires can be improved, and the wet grip performance can be more easily improved. Examples of silica include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, etc. Among these, wet silica is preferred. These silicas may be used alone or in combination of two or more. Silica preferably has a nitrogen adsorption specific surface area (BET method) of 130 m 2 / g or more and less than 330 m 2 / g. When the nitrogen adsorption specific surface area (BET method) of silica is 130 m 2 / g or more, the tire can be sufficiently reinforced and the rolling resistance can be made lower. Also, when the nitrogen adsorption specific surface area (BET method) of silica is less than 330 m 2 / g, the elastic modulus of the tire is not excessively increased and the wet grip performance is excellent. From the viewpoint of further reducing the rolling resistance and improving the abrasion resistance, tear strength, etc. of the tire, the nitrogen adsorption specific surface area (BET method) of silica is more preferably 180 m 2 / g or more, and still more preferably 190 m 2 / g or more. Also, from the viewpoint of further improving the wet grip performance, the nitrogen adsorption specific surface area (BET method) of silica is 300 m 2It is more preferably below / g, 280 m 2 It is more preferably below / g, 270 m 2 It is even more preferably below / g.

[0042] The content of silica in the rubber composition for tires is preferably 30 to 120 parts by mass, more preferably 35 to 100 parts by mass, and even more preferably 40 to 80 parts by mass with respect to 100 parts by mass of the rubber component. When the content of silica in the rubber composition for tires is 30 parts by mass or more, the mechanical strength of the rubber composition for tires can be improved, and the wet grip performance can be more easily improved. Further, when the content of silica is 120 parts by mass or less, the rolling resistance performance can be easily improved. Also, from the viewpoint of improving the mechanical strength of the tire and further improving the rolling resistance performance, the content of silica in the filler is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0043] (Carbon black) The filler preferably further contains carbon black. In particular, carbon black is preferably contained together with silica as a filler, and more preferably contained when the content of silica is in the range of 80% by mass or more. By adding carbon black, the rubber composition for tires can be reinforced and the abrasion resistance can be easily improved. The carbon black is not particularly limited, and examples thereof include carbon blacks of GPF, FEF, HAF, ISAF, and SAF grades. These carbon blacks may be used alone or in combination of two or more.

[0044] The content of carbon black in the rubber composition for tires is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass. When the carbon black content in the rubber composition for tires is 0.5 parts by mass or more, the abrasion resistance of the rubber composition for tires can be easily improved. Also, when the carbon black content is 20 parts by mass or less, the low-loss property of the rubber composition for tires can be easily maintained.

[0045] In the rubber composition for tires of the present invention, the content of the filler is preferably 30 to 120 parts by mass, more preferably 35 to 100 parts by mass, and still more preferably 40 to 80 parts by mass with respect to 100 parts by mass of the rubber component. When the content of the filler in the rubber composition for tires is 30 parts by mass or more, the mechanical strength of the rubber composition for tires can be improved, and the wet grip property can be more easily improved. Also, when the content of the filler is 120 parts by mass or less, the rolling resistance performance can be easily improved.

[0046] (Silane coupling agent) In the rubber composition for tires of the present invention, a silane coupling agent may be blended for the purpose of further improving the reinforcing property of the silica to be blended. Examples of the silane coupling agent include 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-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide, etc. Among these, bis(3-triethoxysilylpropyl)polysulfide and 3-trimethoxysilylpropylbenzothiazyl tetrasulfide are preferred in terms of the effect of improving reinforcement, etc. These silane coupling agents may be used alone or in combination of two or more. In the rubber composition of the present invention, the preferable content of the silane coupling agent varies depending on the type of the silane coupling agent and the like, but is preferably 2 to 25 parts by mass, more preferably 4 to 20 parts by mass, and still more preferably 6 to 15 parts by mass with respect to 100 parts by mass of silica. If the content of the silane coupling agent is 2% by mass or more, the curing of the silane coupling agent can be sufficiently exhibited, and if it is 25% by mass or less, it is easy to suppress the gelation of the rubber component.

[0047] <Other components> In addition to the above rubber component, liquid polymer, resin, and filler, the rubber composition for tires of the present invention can contain compounding agents commonly used in the rubber industry, such as anti-aging agents, vulcanization accelerators, vulcanization acceleration aids, vulcanizing agents, etc., which can be appropriately selected within the range not detrimental to the object of the present invention and compounded within the range of normal compounding amounts. Commercially available products can be preferably used as these compounding agents.

[0048] [Manufacturing method of rubber composition for tires] The manufacturing method of the rubber composition for tires of the present invention is not particularly limited. For example, various components appropriately selected as needed can be compounded into the above rubber component, liquid polymer, resin, and filler, and kneaded, heat-treated, extruded, etc. to produce an unvulcanized rubber composition.

[0049] [Tread member] The tread member of the present invention is a tread member using the above rubber composition for tires of the present invention. As described above, since the rubber composition for tires of the present invention is excellent in workability during the production of the rubber composition and has excellent wet grip performance and rolling performance, the tread member of the present invention is suitable as a tread portion of a vehicle tire. In addition, the above tread member can be manufactured by a normal method using the above rubber composition for tires of the present invention. That is, an unvulcanized tread member can be formed by extruding the above-described rubber composition for a tire according to the tread shape at the unvulcanized stage. By molding the unvulcanized tread member together with other tire members on a tire molding machine by a conventional method, an unvulcanized tire can be formed. By heating and pressurizing the unvulcanized tire in a vulcanizer to vulcanize it, the tire of the present invention described below can be obtained.

[0050] [Tire] The tire of the present invention is a tire using the above-described tread member. As described above, since the rubber composition for a tire of the present invention is excellent in workability during production of the rubber composition and excellent in wet grip performance and rolling performance, the tire of the present invention is suitable as a vehicle tire. In addition, the above tire can be manufactured by a conventional method using the above-described tread member of the present invention. That is, an unvulcanized tire can be formed by extruding the above-described rubber composition for a tire of the present invention according to the tread shape at the unvulcanized stage and molding it together with other tire members on a tire molding machine by a conventional method. By heating and pressurizing the unvulcanized tire in a vulcanizer to vulcanize it, the tire of the present invention can be obtained.

Examples

[0051] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples.

[0052] <Preparation of Rubber Composition for Tire> Based on the formulations shown in Tables 1 to 3, kneading was performed using a Banbury mixer to obtain rubber compositions for tires of Examples and Comparative Examples.

[0053] Details of the materials used in each of the Examples and Comparative Examples in Tables 1 to 3 are as follows. Note that the numerical values of each material in Tables 1 to 3 indicate the compounding amount, and the unit is "parts by mass". (Rubber Component) NR: Natural rubber, "RSS#3" SBR: Styrene-butadiene rubber, manufactured by JSR Corporation, "SBR #1500" (Liquid polymer) Liquid ethylene-α-olefin oligomer: manufactured by Mitsui Chemicals, Inc., "Lucant" (SP value: 8.09 (cal / cm 3 ) 1 / 2 , kinematic viscosity at 40°C: 37,500 mm 2 / s) (Resin) C 5 -series resin: manufactured by Nippon Zeon Co., Ltd., "Quintone M100" (SP value: 8.22 (cal / cm 3 ) 1 / 2 ) C 5 -C 9 -series resin: manufactured by ENEOS Corporation, "T-REZ RD104" (SP value: 9.59 C 9 -series resin: manufactured by ENEOS Corporation, "Neopolymer 140" (SP value: 10.42 (cal / cm 3 ) 1 / 2 ) (Oil) : manufactured by ENEOS Corporation, "Super Oil Y22" (Filler) CB: Carbon black, manufactured by Tokai Carbon Co., Ltd., "Seast 7HM" Silica: manufactured by Tosoh Silica Corporation, "Nipsil AQ" (Silane coupling agent) : manufactured by Evonik Degussa GmbH, "Si75" (Others) Wax: manufactured by Nippon Seiro Co., Ltd., "Oz Ace 0701" 6C: Antioxidant, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., "No Crack 6C" DM: Vulcanization accelerator, di-2-benzothiazolyldisulfide, manufactured by Sanshin Chemical Industry Co., Ltd., "Sunceler DM" NS: Vulcanization accelerator, N-t-butyl-2-benzothiazylsulfenamide, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., trade name "Nocceler NS" DPS: Vulcanization accelerator, 1,3-diphenylguanidine, manufactured by Sanshin Chemical Industry Co., Ltd., trade name "Sanceler D"

[0054] <Evaluation> The rubber compositions of the examples and comparative examples were vulcanized at 160 °C for 15 minutes to obtain vulcanized rubbers. Test pieces were obtained from the resulting vulcanized rubbers and subjected to the following evaluations. 1. Wet grip performance For the rubber compositions for tires of the examples and comparative examples, using a viscoelasticity measuring instrument (ARES rheometer manufactured by TA Instruments), the loss tangent at 0 °C (0 °C tan δ) was measured under the conditions of dynamic strain: 0.1%, frequency 15 Hz, and measurement temperature 0 °C. Regarding the obtained 0 °C tan δ, the value of the control example was set to 100, and the results of each example and comparative example were evaluated as an index. The larger the index, the larger the resistance value and the higher the wet grip performance. An index of 98 or more indicates sufficient wet grip performance. In Table 1, Comparative Example 1 was used as the control example, in Table 2, Comparative Example 4 was used as the control example, and in Table 3, Comparative Example 6 was used as the control example. 2. Rolling resistance performance For the rubber compositions for tires of the examples and comparative examples, using the above viscoelasticity measuring instrument, the loss tangent at 50 °C (50 °C tan δ) was measured under the conditions of dynamic strain: 1%, frequency 15 Hz, and measurement temperature 50 °C. Regarding the reciprocal of the obtained 50 °C tan δ, the value of the control example was set to 100, and the results of each example and comparative example were evaluated as an index. The larger the index, the smaller the resistance value and the higher the rolling resistance performance. An index of 100 or more indicates sufficient rolling resistance performance. In Table 1, Comparative Example 1 was used as the control example, in Table 2, Comparative Example 4 was used as the control example, and in Table 3, Comparative Example 6 was used as the control example.

[0055]

Table 1

[0056]

Table 2

[0057]

Table 3

[0058] From the results of Tables 1 to 3, it can be seen that the rubber composition for tires of the present invention is a rubber composition for tires that is excellent in workability during the production of the rubber composition and excellent in wet grip performance and rolling performance.

Industrial Applicability

[0059] According to the present invention, it is possible to provide a rubber composition for tires, a tread, and a tire that are excellent in workability during the production of the rubber composition and excellent in wet grip performance and rolling performance. Therefore, the present invention can be mainly used in the tire industry and the like.

Claims

1. A rubber composition for tires, comprising a rubber component containing isoprene rubber and a filler, The SP value is 7.95 to 8.45 (cal / cm ３ ) １／２ and a liquid polymer having a kinematic viscosity measured by JIS K2283 at 40°C of 40,000 mm ２ / s or less, and The resin with an SP value of 8.0 to 9.6 (cal / cm ３ ) １／２ and wherein the resin contains at least one selected from the group consisting of C5 resins, hydrogenated C5 resins, C5-C9 resins, hydrogenated C5-C9 resins, cyclopentene resins, cyclopentadiene resins, dicyclopentene resins, dicyclopentadiene resins, and terpene resins.

2. The rubber composition for tires according to Claim 1, wherein the liquid polymer contains, as components constituting the liquid polymer, structural units having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton in a mass ratio of more than 80%.

3. The rubber composition for tires according to Claim 1 or 2, wherein the liquid polymer consists of structural units having an alicyclic hydrocarbon skeleton or an aliphatic hydrocarbon skeleton.

4. The rubber composition for tires according to any one of Claims 1 to 3, wherein the mass ratio (liquid polymer / resin) of the liquid polymer to the resin is 0.5 to 5.

5. The rubber composition for tires according to any one of Claims 1 to 4, wherein the content of isoprene rubber in the rubber component is 5 to 100% by mass.

6. The rubber composition for tires according to any one of Claims 1 to 5, wherein the filler contains silica and carbon black.

7. The rubber composition for tires according to any one of Claims 1 to 6, wherein the content of the filler is 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component.

8. A tread member using the rubber composition for tires according to any one of Claims 1 to 7.

9. A tire using the tread member according to Claim 8. ​

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