JP6835153B2 - Rubber composition for tires and tires - Google Patents

Description

The present invention relates to a rubber composition for a tire and a tire including a tire member composed of the rubber composition.

In recent years, awareness of safety has been increasing more and more as a common issue for automobiles, and further improvement of wet grip performance and steering stability is required. So far, various studies have been conducted to improve wet grip performance, and many inventions of rubber compositions containing silica have been reported. Tire performance depends on various factors such as the structure of the tire and the materials used, and in particular, the performance of the rubber composition of the tread portion in contact with the road surface greatly affects the technical improvement of the rubber composition for tires such as tread. It has been widely studied and put into practical use.

The technical improvement of the rubber composition for tread using silica has made great progress in the wet grip performance of tires. On the other hand, steering stability has not been sufficiently improved and there is room for improvement. In particular, performance changes due to temperature changes due to running in a high temperature region and performance changes when a road surface changes from a wet road surface to a dry road surface remain as important technical issues, and there is room for improvement. In addition, many studies have been conducted on the temperature dependence and road surface dependence of rubber compositions in the cryogenic region, which is the environment in which studless tires are used, but much research has been done on high temperature regions such as dry road surfaces. Absent.

Patent Documents 1 to 3 describe rubber compositions for tires containing a predetermined amount of a predetermined diene rubber and silica, but performance changes (temperature dependence and road surface dependence) in a high temperature region such as a dry road surface. ) Is not considered. Further, Patent Document 4 describes a rubber composition capable of reducing the temperature dependence of hardness, but does not consider the change in performance with respect to the change in road surface from a wet road surface to a dry road surface.

Japanese Unexamined Patent Publication No. 2006-056919 JP-A-2007-197671 Japanese Unexamined Patent Publication No. 2008-101158 Japanese Unexamined Patent Publication No. 2011-089081

The present invention is composed of a rubber composition for a tire, which has little performance change due to a temperature change in a high temperature region, and has a small performance change even when the road surface changes from a wet road surface to a dry road surface, and the rubber composition for the tire. It is an object of the present invention to provide a tire provided with a tire member.

In the present invention, the complex elastic modulus G * _{50 ° C.} at 50 ° C. dynamic strain amplitude 5% and the complex elastic modulus G * _{100 ° C.} at 100 ° C. dynamic strain amplitude 5% satisfy the following equation (1), and 23. The present invention relates to a rubber composition for a tire in which a _{breaking elongation EB 23 ° C.} by a tensile test at ° C. is 350% or more, and a tangent loss tan δ _{50 ° C. at 50 ° C. dynamic strain amplitude 1% is 0.12 or more.}
Equation (1) G * _{100 ° C} / G * _{50 ° C} > 0.85

Further, it is preferable that the elongation at break EB _{100 ° C. by the tensile test at 100 ° C.} and the modulus M 100 ° C. at the time of 100% stretching at 100 ° C. satisfy the following formula (2).
Equation (2) 2500 <EB _{100 ° C} x M _{100 ° C} <4500

Further, the shore hardness HS at _{50 ° C.} , the complex elastic modulus E * at 50 ° C. dynamic strain amplitude of 1%, and the tangent loss tan δ _{50 ° C.} at 50 ° C. dynamic strain amplitude of 1% are expressed by the following equations (3). ) Is preferably satisfied.
Equation (3) 0.05 <(tan δ _{50 ° C} ) ² / (E * × HS _{50 ° C} ) × 1000

Furthermore, tangent loss at 0.25% dynamic strain amplitude at each temperature from -10 ° C to 20 ° C in 5 ° C increments tanδ _{-10 ° C} , tanδ _{-5 ° C} , tanδ _{0 ° C} , tanδ _{5 ° C} , tanδ _{10 ° C} , It is preferable that tan δ _{15 ° C.} and tan δ _{20 ° C.} satisfy the following formula (4).
Equation (4) 2.5 <tanδ _{-10 ℃} ＋ tanδ _{-5 ℃} ＋ tanδ _{0 ℃} ＋ tanδ _{5 ℃} ＋ tanδ _{10 ℃} ＋ tanδ _{15 ℃} ＋ tanδ _{20 ℃} <4.5

It is preferable to contain a rubber component containing 50% by mass or more of diene-based rubber having a styrene content of 25 to 50% by mass and a vinyl bond amount of 10 to 35 mol%.

It is preferable that the styrene content is twice or more the vinyl bond amount.

It is preferable that 5 to 150 parts by mass of silica having a nitrogen adsorption specific surface area of 50 m ^{2 / g or more is contained with respect to 100 parts by mass of the rubber component.}

The present invention also relates to a tire provided with a tire member composed of the rubber composition.

According to the present invention, the complex elastic modulus G * _{50 ° C.} at 50 ° C. dynamic strain amplitude 5% and the complex elastic modulus G * _{100 ° C.} at 100 ° C. dynamic strain amplitude 5% satisfy a predetermined equation, and 23. _{By using a rubber composition for tires in which the tangent loss tan δ 50 °} C at a breaking elongation EB _{23 ° C} and a dynamic strain amplitude of 1% at 50 ° C by a tensile test at ° C is within a predetermined range, the temperature changes due to running in a high temperature range. Provided are a rubber composition for a tire having a small change in performance due to a change in performance and a small change in performance even when the road surface changes from a wet road surface to a dry road surface, and a tire provided with a tire member composed of the rubber composition for the tire. be able to.

In the rubber composition for tires of the present invention, the complex elastic modulus G * _{50 ° C.} at 50 ° C. dynamic strain amplitude 5% and the complex elastic modulus G * _{100 ° C.} at 100 ° C. dynamic strain amplitude 5% are expressed by the following formulas ( It is characterized in that 1) is satisfied, the breaking elongation EB _{23 ° C.} by a tensile test at 23 ° C., and the tangential loss tan δ _{50 ° C.} at 50 ° C. dynamic strain amplitude 1% are within a predetermined range.
Equation (1) G * _{100 ° C} / G * _{50 ° C} > 0.85

The complex elastic modulus G * in the present specification indicates the complex elastic modulus at the time of torsional shear measured by the rheometer ARES manufactured by TA Instruments. By measuring the value of the complex elastic modulus with a rheometer, it is possible to investigate the rubber characteristics close to the situation where a high strain is applied when turning on a dry road surface by an actual vehicle equipped with tires. Further, by setting the temperature, it is possible to investigate when the tire surface temperature is the set temperature. _{That is, G * 50 ° C} in the formula (1) is an index of tire characteristics when a tire having a tire surface temperature of 50 ° C turns on a dry road surface, and G * _{100 ° C} is a tire having a tire surface temperature of 100 ° C. It is an index of tire characteristics when turning on a dry road surface.

Further, when the vehicle is driven by a general vehicle in the summer, the tire surface temperature is around 50 ° C immediately after use, and reaches the range of 70 ° C to 80 ° C during traveling. Furthermore, it reaches the 100 ° C. range when traveling at high speed on the Autobahn in Europe. _{That is, G * 50 ° C} in the formula (1) is an index of tire characteristics on the dry road surface of the tire immediately after use, and G * _{100 ° C} is an index of tire characteristics in a high temperature region such as when traveling on a dry road surface at high speed. Is.

That is, the closer the value of the equation (1) is to 1, the _{smaller the change between the performance immediately after use on a dry road surface (G * 50 ° C} ) and the performance in a high temperature range (G * _{100 ° C} ), and in the high temperature range Indicates that there is little change in performance.

It is extremely important that the value of the formula (1) exceeds 0.85 in order to obtain a rubber composition having little change in performance, and it is preferably more than 0.88 and more preferably 0.92. When the value of the formula (1) is 0.85 or less, the performance change in the high temperature region is large, and the performance tends to change so that the driver can feel it. As described above, the upper limit of the value of the formula (1) is preferably 1 or less.

_{The tangent loss tan δ 50 °} C. at the breaking elongation EB _{23 ° C.} and 50 ° C. dynamic strain amplitude 1% by the tensile test at 23 ° C. is an index of strength, durability and grip characteristics which are indispensable for a rubber composition for a tire. ..

The elongation at break EB _{23 ° C.} by the tensile test at 23 ° C. is 350% or more, preferably 450% or more, and more preferably 550% or more. When the EB _{23 ° C.} is less than 350%, the strength of the rubber composition for tires is not sufficient, and the durability tends to be insufficient. The upper limit of EB _{23 ° C.} is not particularly limited, but 700% or less is preferable, and 650% or less is more preferable, because the broken rubber is appropriately cut off from the rubber surface and a good wear appearance can be obtained.

_{The tangent loss tan δ 50 °} C. at 50 ° C. dynamic strain amplitude 1% is 0.12 or more, preferably 0.17 or more. When tan δ _{50 ° C.} is less than 0.12, the energy loss is too low, so that the grip characteristics required for the tire cannot be obtained, and there is a tendency that sufficient safety cannot be ensured. The upper limit of tan δ _{50 ° C.} is not particularly limited, but is preferably 0.45 or less, more preferably 0.40 or less, from the viewpoint of suppressing heat generation of rubber and improving durability.

One of the factors that affect the performance change between the tire immediately after use on a dry road surface and the tire in a high temperature region such as when traveling on a dry road surface at high speed is the influence of the wear form of the cap tread rubber in contact with the road surface. When a certain external force or deformation amount is applied to the cap tread or the like, the rubber breaks and is cut off from the rubber surface, showing a good wear appearance. On the other hand, if the strength of the rubber is too high with respect to the external force, the rubber is not cut off and remains in a stretched state on the surface, and wear marks having specific protrusions are generated. The presence of these wear marks reduces the contact area with the road surface, causing a decrease in grip force. In addition, specific protrusions are broken, and break marks are generated.

The occurrence of the wear marks and break marks can be suppressed by using a rubber composition having a specific rubber strength. In the present invention, _{the product of the elongation at break EB 100 ° C. by a tensile test at 100 ° C.} and the modulus M 100 ° C. at 100 ° C. 100% stretching is used as an index of the rubber strength, and it is preferable to satisfy the following formula (2).
Equation (2) 2500 <EB _{100 ° C} x M _{100 ° C} <4500

The value of the formula (2) preferably exceeds 2500, more preferably more than 3200, and even more preferably more than 3800. When the value of the formula (2) is 2500 or less, the rubber strength is low and wear marks such as cracks tend to occur, and the cracks may grow and cause damage such as chipping of the tread rubber block. is there. The value of the formula (2) is preferably less than 4500, more preferably less than 4200, and even more preferably less than 4000. When the value of the formula (2) is 4500 or more, the effect of suppressing the abrasion marks having the protrusions tends to be insufficiently exhibited.

As described above, the rubber composition of the present invention is a rubber composition for tires that suppresses a decrease in complex elastic modulus due to a temperature change in a high temperature range and has a small performance change by satisfying the formula (1). On the other hand, since the complex elastic modulus does not decrease due to the temperature rise, the road noise of the tire may be deteriorated. Road noise is an important tire characteristic related to noise problems as well as regulations have begun in Europe.

The generation of road noise is considered to contribute to the vibration of rubber generated when sliding on the road surface, and can be explained by the propagation and damping force of the vibration. In the present invention, the propagation of vibration contributes to the rigidity of the rubber, and the propagation of vibration due to the deformation of the contact surface between the rubber and the road surface is based on the tire block with the complex elastic modulus E * at 50 ° C. dynamic strain amplitude of 1% as an index. It is preferable that the vibration propagation uses the shore hardness HS of _{50 ° C.} at 50 ° C. as an index, and the damping force uses the tangential loss tan δ _{50 ° C.} at 50 ° C. dynamic strain amplitude of 1% as an index and satisfies the following equation (3).
Equation (3) 0.05 <(tan δ _{50 ° C} ) ² / (E * × HS _{50 ° C} ) × 1000

The larger the value of the formula (3), the smaller the road noise, and the tire can be suitably used. The value of the formula (3) preferably exceeds 0.05, more preferably 0.07, and even more preferably 0.09. If the value of equation (3) is 0.05 or less, the road noise tends to deteriorate and the market demands tend not to be fully satisfied, and further, there is a risk of squealing noise when changing lanes. is there.

Furthermore, in order to reduce the performance change due to the road surface change from the wet road surface to the dry road surface, it is necessary to consider the viscoelastic characteristics close to the temperature condition of the dry road surface. In addition, considering the wet skid performance on various road surfaces, the characteristics at multiple frequencies should be taken into consideration. Using the frequency-temperature conversion law, if the following equation (4) is satisfied, it will be stable under various environments. It is a rubber composition for tires that can exhibit wet skid performance.

Using the frequency-temperature conversion law, tangent loss at 0.25% dynamic strain amplitude at each temperature from -10 ° C to 20 ° C in 5 ° C increments tanδ _{-10 ° C} , tanδ _{-5 ° C} , tanδ _{0 ° C} , tanδ _{5 It is preferable that ° C.} , tanδ _{10 ° C.} , tanδ _{15 ° C.} and tanδ _{20 ° C.} satisfy the following formula (4). By satisfying the formula (4), the wet skid performance can be stably exhibited even in various environments.
Equation (4) 2.5 <tanδ _{-10 ℃} ＋ tanδ _{-5 ℃} ＋ tanδ _{0 ℃} ＋ tanδ _{5 ℃} ＋ tanδ _{10 ℃} ＋ tanδ _{15 ℃} ＋ tanδ _{20 ℃} <4.5

The value of the formula (4) is preferably more than 2.5, more preferably more than 2.7, and even more preferably more than 3.0. When the value of the formula (4) is 2.5 or less, sufficient wet skid performance and dry grip performance tend not to be obtained. Further, the larger the value of the formula (4) is, the more the wet skid performance and the dry grip performance tend to satisfy the market demand, but usually it is less than 4.5.

The rubber composition for tires of the present invention is preferably a rubber composition for tires containing a specific rubber component.

Examples of the rubber component include diene rubber, and examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), and acrylonitrile butadiene rubber (NBR). ), Chloroprene rubber (CR), butyl rubber (IIR), styrene-isoprene-butadiene copolymer rubber (SIBR) and the like. These diene-based rubbers can be used alone or in combination of two or more. Of these, NR, BR, and SBR are preferable, and SBR is more preferable, because grip performance and wear resistance can be obtained in a well-balanced manner. It should be noted that the combined use of NR and SBR, the combined use of BR and SBR, and the combined use of NR, BR and SBR are also suitable.

Further, as the diene rubber, it is possible to use a diene rubber having a styrene content of 25 to 50% by mass and a vinyl bond amount of 10 to 35 mol% for wet skid performance, dry grip performance and low fuel consumption. Is preferable because it can be obtained in a well-balanced manner. Examples of the diene rubber containing styrene and vinyl include SBR and SIBR.

The styrene content of the diene rubber is preferably 25% by mass or more, more preferably 30% by mass or more, and further preferably 35% by mass or more. When the styrene content is less than 25% by mass, it is difficult to obtain a rubber composition satisfying the formula (4) on both dry and wet road surfaces, and the grip performance is not sufficient. The styrene content of the diene rubber is preferably 50% by mass or less, more preferably 45% by mass or less, and further preferably 42% by mass or less. When the styrene content exceeds 50% by mass, the glass transition temperature of the rubber composition rises too much, the temperature dependence becomes high, and it tends to be difficult to satisfy the formulas (1) and (4).

The vinyl bond amount of the diene rubber is preferably 10 mol% or more, more preferably 15 mol% or more, still more preferably 18 mol% or more. When the vinyl bond amount is less than 10 mol%, the reactivity with silica is poor, and the rubber strength and wear resistance tend to decrease. The vinyl bond amount of the diene rubber is preferably 35 mol% or less, more preferably 30 mol% or less, further preferably 25 mol% or less, and most preferably 23 mol% or less. When the vinyl bond amount exceeds 35 mol%, the glass transition temperature of the rubber composition rises too much, the temperature dependence becomes high, and it tends to be difficult to satisfy the formulas (1) and (4).

When a diene-based rubber having a predetermined styrene content and vinyl bond amount is contained, the content of the diene-based rubber in the rubber component is preferably 50% by mass or more, more preferably 70% by mass or more. When the content of the diene rubber is less than 50% by mass, it becomes difficult to satisfy the formula (1), and the performance change in a high temperature range tends to be large. The content of the diene-based rubber is preferably 100% by mass because it satisfies the formula (1) and the change in performance in a high temperature range is small, but 95% by mass when used in combination with other rubber components. It can be less than or equal to 90% by mass or less.

Further, the diene rubber preferably has a styrene content of 2 times or more, more preferably 2.2 times or more, and 2.5 times or more of the vinyl bond amount, for the reason of achieving both wet skid performance and low fuel consumption. Is even more preferable. Although the upper limit is not particularly limited, the diene rubber preferably has a styrene content of 3.0 times or less the vinyl bond amount. When the styrene content exceeds 3.0 times the vinyl bond amount, the glass transition temperature tends to rise too much, and fuel efficiency and low temperature characteristics tend to be significantly reduced.

The SBR is not particularly limited, and for example, emulsified polymerization SBR (E-SBR) obtained by emulsification polymerization, solution polymerization SBR (S-SBR) obtained by solution polymerization, and modified SBR obtained by modifying these SBRs ( Various SBRs such as modified E-SBR and modified S-SBR) can be used. Of these, S-SBR is preferable because it can satisfactorily improve fuel efficiency and wear resistance.

The NR is not particularly limited, and examples thereof include those common in the tire industry such as SIR20, RSS # 3, and TSR20.

The BR is not particularly limited, and for example, BR (Hisys BR) having a cis content of 95% or more, rare earth butadiene rubber (rare earth BR) synthesized using a rare earth element catalyst, and syndiotactic polybutadiene crystals. BR (SPB-containing BR) containing, modified BR, etc., which are common in the tire industry can be used. Among them, it is preferable to use HISIS BR from the viewpoint of excellent wear resistance.

When BR is contained, the content of BR in the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more. When the content of BR is less than 5% by mass, it tends to be difficult to obtain the effect of improving wear resistance. The BR content is preferably 35% by mass or less, more preferably 25% by mass or less. When the BR content exceeds 35% by mass, the dry grip performance tends to be significantly reduced.

The rubber composition for tires of the present invention contains the rubber component as a compounding agent generally used in the production of rubber compositions, for example, a reinforcing filler such as silica and carbon black, zinc oxide, stearic acid, and various anti-aging agents. Agents, oils such as aroma oil, vulcanizing agents such as wax and sulfur, various vulcanization accelerators and the like can be appropriately contained.

The silica is not particularly limited, and examples thereof include dry silica (silicic anhydride) and wet silica (silicic anhydride), and wet silica is preferable because it has a large amount of silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of ^{silica is preferably 50 m 2} / g or more, and more preferably 100 m ² / g or more. When the N ₂ SA of ^{silica is less than 50 m 2} / g, the reinforcing property is not sufficient and the rubber strength tends to be insufficient. The N ₂ SA of the silica is preferably 250 meters ² / g or less, more preferably 200m ² / g. When the N ₂ SA of ^{silica exceeds 250 m 2} / g, it becomes difficult to sufficiently disperse silica in the kneaded product, and fuel efficiency and wear resistance tend to decrease. _{The N 2} SA of silica in the present invention is a value measured according to the method A of JIS K 6217.

When silica is contained, the content of silica with respect to 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 60 parts by mass or more, and further preferably 80 parts by mass or more. When the content of silica is less than 5 parts by mass, it is difficult to obtain a sufficient reinforcing effect of silica, and the durability tends to decrease. The silica content is preferably 150 parts by mass or less, more preferably 130 parts by mass or less, and further preferably 110 parts by mass or less. When the silica content exceeds 150 parts by mass, the rubber tends to be too hardened and it becomes difficult to satisfy the formula (4).

When silica is contained, it is preferable to use a silane coupling agent together with silica. The silane coupling agent can be used alone or in combination of several types. Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2-triethoxy). Cyrilethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyl Trimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxy Cyrilethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazolyltetrasulfide, 3-triethoxysilylpropylmethacrylate monosulfide, 3-tri Methoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyl dimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, dimethoxymethylsilylpropylbenzothiazoletetra Examples include sulfide. In particular, it is preferable to use bis (3-triethoxysilylpropyl) disulfide because it is relatively inexpensive and easy to process.

When the silane coupling agent is contained, the content of the silane coupling agent with respect to 100 parts by mass of silica is preferably 3 parts by mass or more, more preferably 5 parts by mass or more. When the content of the silane coupling agent is less than 3 parts by mass, the coupling effect is insufficient and high silica dispersion cannot be obtained, so that the fuel efficiency performance and the breaking strength tend to decrease. The content of the silane coupling agent is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less. When the content of the silane coupling agent exceeds 15 parts by mass, excess silane coupling agent remains, and the processability and fracture characteristics of the obtained rubber composition tend to deteriorate.

It is preferable to contain carbon black because good wet grip performance and wear resistance can be obtained more preferably. As the carbon black, for example, GPF, HAF, ISAF, SAF and the like, which are common in the tire industry, can be used.

The BET specific surface area of carbon black ^{is preferably 50 m 2} / g or more, more preferably 100 m ² / g or more, and even more preferably 120 m ² / g or more. If the BET specific surface area is ^{less than 50 m 2} / g, sufficient wet grip performance and wear resistance may not be obtained. Further, BET specific surface area of carbon black is preferably not more than ^{200m 2 / g, 180m 2 /} g or less is more preferable. When the BET specific surface area ^{exceeds 200 m 2} / g, it becomes difficult to disperse and the wear resistance tends to deteriorate. The BET specific surface area of carbon black is a value measured by the BET method according to ASTM D6556.

The dibutyl phthalate oil absorption (DBP) of carbon black is preferably 50 ml / 100 g or more, and more preferably 100 ml / 100 g or more. If the DBP is less than 50 ml / 100 g, sufficient wet grip performance and wear resistance may not be obtained. The carbon black DBP is preferably 220 ml / 100 g or less, more preferably 180 ml / 100 g or less. If the DBP exceeds 220 ml / 100 g, it becomes difficult to disperse and the wear resistance tends to deteriorate. The carbon black DBP is measured in accordance with JIS K6217-4: 2001.

When carbon black is contained, the content of carbon black with respect to 100 parts by mass of the rubber component is preferably 3 parts by mass or more, and more preferably 5 parts by mass or more. When the content of carbon black is less than 3 parts by mass, deterioration due to ultraviolet rays tends to be promoted easily. The content of carbon black is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. If the carbon black content exceeds 50 parts by mass, the wet grip performance may deteriorate. In addition, it becomes difficult to disperse, and the wear resistance may deteriorate.

The method for producing the rubber composition for a tire of the present invention is not particularly limited, and a known method can be used. For example, each of the above components can be kneaded using a rubber kneading device such as an open roll, a Banbury mixer, or a closed kneader, and then vulcanized.

The rubber composition for a tire of the present invention can be suitably used for a tire tread, particularly a tire cap tread, because it can suppress a change in performance against a strong stimulus such as contact with a road surface.

The tire of the present invention is produced by a usual method using the rubber composition for a tire of the present invention. That is, the rubber composition for a tire of the present invention is extruded according to the shape of each tire member at the unvulcanized stage, and is molded together with other tire members by a normal method on a tire molding machine. , Mold unvulcanized tires. A tire is obtained by heating and pressurizing this unvulcanized tire in a vulcanizer.

The tire of the present invention comprises the rubber composition of the present invention in which the rubber component according to the present invention is blended according to the above method, that is, the above-mentioned compounding agent is blended with the rubber component as necessary, at the stage of unvulcanization. An unvulcanized tire is obtained by extruding according to the shape of each tire member, laminating with other tire members on a tire molding machine, and molding by a usual method, and this unvulcanized tire is added. The tire of the present invention can be manufactured by heating and pressurizing in a vulcanizer.

The tire of the present invention is suitably used as a tire for a passenger car, a tire for a truck / bus, a tire for a two-wheeled vehicle, a tire for a competition, and the like. Used.

The present invention will be specifically described based on Examples, but the present invention is not limited thereto.

Hereinafter, various chemicals used in Examples and Comparative Examples will be collectively described.
SBR1: SBR (modified S-SBR, styrene content: 25% by mass, vinyl bond amount: 59 mol%, non-oil-extended product) obtained by the method shown in the production of SBR1 described later.
SBR2: T3830 manufactured by Asahi Kasei Corporation (S-SBR, styrene content: 33% by mass, vinyl bond amount: 36 mol%, oil-extended product containing 37.5 parts by weight of oil with respect to 100 parts by weight of rubber component)
SBR3: HP755B manufactured by JSR Corporation (S-SBR, styrene content: 37% by mass, vinyl bond amount: 37 mol%, oil-extended product containing 37.5 parts by weight of oil with respect to 100 parts by weight of rubber component)
SBR4: SLR6430 manufactured by Dow Chemical Co., Ltd. (S-SBR, styrene content: 40% by mass, vinyl bond amount: 18 mol%, oil-extended product containing 37.5 parts by weight of oil with respect to 100 parts by weight of rubber component)
SBR5: Nippon Zeon Co., Ltd. Nipol 9549 (E-SBR, styrene content: 40% by mass, vinyl bond amount: 18 mol%, oil spread product containing 37.5 parts by weight of oil with respect to 100 parts by weight of rubber component )
BR: BR150B manufactured by Ube Industries, Ltd. (cis content 97%)
Carbon black: Tokai Carbon Co., Ltd. Seast 9H (DBP oil absorption 115 ml / g, BET specific surface area 110 m ² / g)
Silica: ZEOSIL 1165MP manufactured by Rhodia (N ₂ SA: 160m ² / g)
Silane coupling agent: Silane coupling agent Si75 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Degussa.
Aroma oil: Process X-140 manufactured by Japan Energy Co., Ltd.
Anti-aging agent: Santoflex 13 manufactured by Flexis
Stearic acid: Stearic acid "Camellia" manufactured by NOF CORPORATION
Zinc oxide: Zinc oxide type 2 manufactured by Mitsui Metal Mining Co., Ltd. Sulfur: Powdered sulfur vulcanization accelerator manufactured by Tsurumi Chemical Industry Co., Ltd. 1: Noxeller NS (N-tert-) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Butyl-2-benzothiazyl sulfenamide)
Vulcanization accelerator 2: Noxeller D (1,3-diphenylguanidine) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.

Production of SBR1 The inside of a stainless steel polymerization reactor with an internal volume of 20 liters was washed, dried, replaced with dry nitrogen, hexane (specific gravity 0.68 g / cm ³ ) 10.2 kg, 1,3-butadiene (Tokyo Chemical Industry (Tokyo Chemical Industry)). Polymerization reactor with 547 g (manufactured by Kanto Chemical Co., Ltd.), 173 g of styrene (manufactured by Kanto Chemical Co., Ltd.), 6.1 ml of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.), and 5.0 ml of ethylene glycol diethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) I put it in. Next, an n-hexane solution prepared by dissolving 13.1 mmol of n-butyllithium (1.6M n-butyllithium hexane solution manufactured by Kanto Chemical Co., Inc.) in n-hexane (manufactured by Kanto Chemical Co., Inc.) was added. Then, polymerization was started. The stirring speed was 130 rpm, the temperature inside the polymerization reactor was 65 ° C., and the copolymerization of 1,3-butadiene and styrene was carried out for 3 hours while continuously supplying the monomers into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g. Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 11.1 mmol of 3-diethylaminopropyltriethoxysilane was added, and the mixture was stirred for 15 minutes. 20 ml of a hexane solution containing 0.54 ml of methanol was added to the polymer solution, and the polymer solution was further stirred for 5 minutes. 2-tert-Butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenylacrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer GM) in the polymer solution 1. Add 8 g and 0.9 g of pentaerythrityltetrakis (3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer TP-D), and then SBR1 from the polymer solution by steam stripping. Was recovered.

Measurement of vinyl bond amount (unit: mol%)
The vinyl bond amount of the polymer was determined from the absorption intensity near ^{910 cm -1,} which is the absorption peak of the vinyl group, by infrared spectroscopic analysis.

Measurement of styrene content (unit: mass%)
According to JIS K6383 (1995), the content of the styrene unit of the polymer was determined from the refractive index.

Examples 1-8 and Comparative Examples 1-4
According to the formulation shown in Table 1, chemicals other than sulfur and the vulcanization accelerator were kneaded at a discharge temperature of 160 ° C. for 4 minutes using a 1.7 L sealed Bunbury mixer to obtain a kneaded product. Next, using an open roll, sulfur and a vulcanization accelerator were added to the obtained kneaded product and kneaded for 4 minutes to obtain an unvulcanized rubber composition. Further, the obtained unvulcanized rubber composition was press-vulcanized for 12 minutes under the condition of 170 ° C. to obtain a test vulcanized rubber sheet.

Further, using the obtained unvulcanized rubber composition, each rubber sheet was prepared so as to have the shape of a tread rubber portion, and this was bonded together with other members to prepare a raw tire. Next, in the vulcanization step, press molding was performed at 170 ° C. for 20 minutes to prepare a 195 / 65R15 size test tire.

Using the obtained test vulcanized rubber sheet and test tire, evaluation was performed by the method shown below. The evaluation results are shown in Table 1.

<Complex elastic modulus G * measurement>
A test piece having a diameter of 10 mm and a thickness of 2 mm was punched out from each test vulcanized rubber sheet, and a dynamic strain amplitude of 5%, a frequency of 10 Hz, a temperature of 50 ° C. and a temperature of 100 ° C. were used using a rheometer ARES 2G manufactured by TA Instruments. The complex elastic modulus G * was measured below.

<Measurement of elongation at break EB and modulus M>
According to JIS K6251 "Vulcanized rubber and thermoplastic rubber-How to determine tensile properties", using a No. 3 dumbbell type test piece made of vulcanized rubber sheets for each test, under the conditions of temperatures of 23 ° C and 100 ° C. A tensile test was carried out, and the elongation at break (EB) and the modulus (M) at 100% stretching at 100 ° C. were measured.

<Measurement of tangent loss tan δ and complex elastic modulus E *>
Using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd., tan δ and E * were measured under the conditions of a dynamic strain amplitude of 1%, a frequency of 10 Hz, and a temperature of 50 ° C. for each test vulcanized rubber sheet. In addition, tan δ was measured at each temperature of dynamic strain amplitude 0.25%, frequency 10 Hz, and temperature -10 ° C to 20 ° C in 5 ° C increments.

<Shore hardness HS measurement>
The shore hardness (HS) of each test vulcanized rubber sheet at a temperature of 50 ° C. was measured using a durometer type A in accordance with JIS K6253.

<Dry steering stability test>
Each test tire was attached to all wheels of the domestic FF2000cc, and a test run was carried out on eight laps of a test course of 3km per lap. Then, by the sensory evaluation of the driver, the initial dry steering stability and the dry steering stability after the performance change were relatively evaluated with the result of the initial dry steering stability in Comparative Example 1 as 6 points. The initial dry steering stability indicates the dry steering stability on the 1st to 3rd laps, and the dry steering stability after the performance change indicates the dry steering stability on the 4th to 8th laps. The higher the score, the better the dry steering stability, and the smaller the difference between the scores on the 3rd and 8th laps, the smaller the change in performance.

<Abrasion resistance test>
The appearance of the test tire after the test run (running 8 laps on a test course of about 3 km per lap) was visually observed and evaluated by the presence or absence of specific protrusion wear marks or fracture marks. Those with specific protrusion wear marks or break marks were marked with "x", and those without specific protrusions were marked with "○". Those with "○" indicate that they have excellent wear resistance.

<Noise evaluation>
Each test tire was attached to all wheels of the vehicle (domestic FF2000cc), and the road noise measurement road (rough asphalt road) was run at a speed of 60 km / h. The noise inside the vehicle at that time is shown by a 10-point method with 6 points in Comparative Example 1 based on the sensory evaluation of the driver. The higher the score, the less noise inside the vehicle and the better the noise characteristics.

<Wet grip performance test>
Each test tire was attached to all wheels of the vehicle (domestic FF2000cc), and the braking distance was measured by stepping on the brake while traveling at an initial speed of 100 km / h on a wet asphalt road surface and a wet concrete road surface. Then, the index was displayed by the following formula. The larger the index, the better the wet grip performance.
(Wet grip figure of merit) =
(Brake distance of asphalt road surface of Comparative Example 1) / (Brake distance of each combination) × 100

From the results in Table 1, the rubber composition of the present invention is a rubber composition for tires, which has little performance change due to temperature change in a high temperature range and little performance change even when the road surface changes from a wet road surface to a dry road surface. It turns out that there is.

Claims (12)

90 parts by mass or more of silica is contained with respect to 100 parts by mass of a rubber component containing styrene-butadiene rubber and / or styrene-isoprene-butadiene copolymer rubber.
The complex elastic modulus G * _{50 ° C.} at 50 ° C. dynamic strain amplitude 5% and the complex elastic modulus G * _{100 ° C.} at 100 ° C. dynamic strain amplitude 5% satisfy the following equation (1).
The elongation at break EB _{23 ° C} by the tensile test at 23 ° C is 350% or more.
Passenger car tire having a tire member which is composed of a tangent loss tan [delta _{50 ° C.} 0.19 or higher der Lugo rubber composition at 50 ° C. dynamic strain amplitude of 1%.
Equation (1) G * _{100 ° C} / G * _{50 ° C} > 0.85 It contains styrene-butadiene rubber and / or styrene-isoprene-butadiene copolymer rubber, and the content of butadiene rubber in the rubber component is 5 to 25% by mass.
Complex elastic modulus G * at 50 ° C. dynamic strain amplitude 5% _{50 ℃} And the complex elastic modulus G * at 100 ° C. dynamic strain amplitude 5% _{100 ℃} And satisfy the following formula (1)
Elongation EB by tensile test at 23 ° C _{23 ℃} Is over 350%
Tangent loss tan δ at 50 ° C dynamic strain amplitude 1% _{50 ℃} A passenger car tire comprising a tire member composed of a rubber composition having a value of 0.19 or more.
Equation (1) G * _{100 ℃} / G * _{50 ℃} > 0.85 The tangent loss tan δ of the rubber composition at 50 ° C. dynamic strain amplitude 1% _{50 ℃} The passenger car tire according to claim 1 or 2, wherein the tire is 0.21 or more. The tangent loss tan δ of the rubber composition at 50 ° C. dynamic strain amplitude 1% _{50 ℃} The passenger car tire according to claim 1 or 2, wherein the tire is 0.25 or more. Wherein the rubber composition, and elongation at break EB _{100 ° C.} by a tensile test at 100 ° C., and a 100 ° C. 100% modulus M _{100 ° C.} at the time of stretching, any one of claims 1-4 which satisfy the following formula (2) Passenger car tires described in the section .
Equation (2) 2500 <EB _{100 ° C} x M _{100 ° C} <4500 The rubber composition has a _{shore hardness HS of 50 °} C. at 50 ° C., a complex elastic modulus E * at 50 ° C. dynamic strain amplitude of 1%, and a tangent loss of tan δ _{50 ° C.} at 50 ° C. dynamic strain amplitude of 1%. The passenger car tire according to any one of claims 1 to 5, which satisfies the following formula (3).
Equation (3) 0.05 <(tan δ _{50 ° C} ) ² / (E * × HS _{50 ° C} ) × 1000 The tangent loss of the rubber composition at each temperature of -10 ° C to 20 ° C in 5 ° C increments with a dynamic strain amplitude of 0.25% tan δ _{-10 ° C} , tan δ _{-5 ° C} , tan δ _{0 ° C} , tan δ _{5 ° C} , The passenger car tire according to any one of claims 1 to 6 , wherein tan δ _{10 ° C. , tan δ 15 ° C.} and tan δ _{20 ° C.} satisfy the following formula (4).
Equation (4) 2.5 <tanδ _{-10 ℃} ＋ tanδ _{-5 ℃} ＋ tanδ _{0 ℃} ＋ tanδ _{5 ℃} ＋ tanδ _{10 ℃} ＋ tanδ _{15 ℃} ＋ tanδ _{20 ℃} <4.5 The rubber component is, according to any one of the diene rubber of 50 wt% or more including請Motomeko 1-7 vinyl bond content styrene content is 25 to 50 mass% is 10 to 35 mol% Passenger car tires . The passenger car tire according to claim 8, wherein the styrene content is at least twice the vinyl bond amount. The passenger car tire according to any one of claims 1 or 3 to 9 , wherein the content of butadiene rubber in the rubber component is 25% by mass or less. The passenger car tire according to any one of claims 2 to 10 , wherein the rubber composition contains 80 to 150 parts by mass of silica with respect to 100 parts by mass of the rubber component. The passenger car tire according to any one of claims 1 to 11 , wherein the rubber composition contains 5 to 150 parts by mass of silica having a nitrogen adsorption specific surface area of 50 m ^{2 / g or more with respect to 100 parts by mass of the rubber component.} ..