JP2017165409A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire in which fuel economy, wet grip performance, driving stability, wear resistance, fatigue resistance and fracture strength are improved in a balanced manner.SOLUTION: The present invention provides a pneumatic tire having a tread made with a rubber composition of which rubber physical properties after vulcanization satisfy following formulas.SELECTED DRAWING: None

Description

The present invention relates to a pneumatic tire.

In recent years, from the viewpoint of increasing interest in environmental issues and economic efficiency, there has been a strong demand for lower fuel consumption for automobiles, and automobile tires are also required to have excellent fuel efficiency. By reducing the amount of filler such as silica or carbon black, rolling resistance can be reduced and fuel efficiency can be improved, but on the other hand, wet grip performance and wear resistance tend to be reduced. Further, in automobile tires, steering stability, fatigue resistance, and fracture resistance are also required. Therefore, a method for improving the fuel economy, wet grip performance, steering stability, wear resistance, fatigue resistance and fracture resistance in a well-balanced manner is required.

Until now, a method in which a specific rubber component, silica, and inorganic powder such as aluminum hydroxide are appropriately combined to achieve both performance on a wet road surface, wear resistance, and low heat generation (for example, Patent Document 1) And a method of improving grip performance and workability on wet road surfaces and semi-wet road surfaces by appropriately combining a specific rubber component, a specific inorganic compound powder, and a specific carbon black (see, for example, Patent Document 2) ), A method of improving grip strength on wet road surfaces and semi-wet road surfaces by appropriately combining a specific rubber component, a specific inorganic compound powder, a specific silica and a specific carbon black without impairing the wear resistance. (See, for example, Patent Document 3), but low fuel consumption, wet grip performance, steering stability, wear resistance, fatigue resistance and resistance In terms of improving well-balanced 壊強 degree there is still room for improvement.

Japanese Patent No. 3745105 Japanese Patent No. 3366452 Japanese Patent No. 3366453

An object of the present invention is to solve the above-mentioned problems and to provide a pneumatic tire in which fuel economy, wet grip performance, steering stability, wear resistance, fatigue resistance and fracture strength are improved in a well-balanced manner. .

The present invention is a pneumatic tire having a tread produced using a rubber composition, and the rubber physical properties after vulcanization of the rubber composition satisfy all of the following formulas (1) to (7) About.

In the above formulas (1) and (5), tan δ ₁ represents tan δ at 0 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 5%.
Tan δ ₂ in the above formulas (1), (2) and (4) represents tan δ at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%.
E ^* in the above formulas (2) and (3) represents a dynamic elastic modulus (E ^* [MPa]) at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%.
EB in the above formulas (6) and (7) represents tensile elongation (EB [%]) measured according to JIS K6251.
TB in said formula (7) represents the tensile breaking strength (TB [MPa]) measured based on JISK6251.

It is preferable that the rubber physical properties after vulcanization of the rubber composition further satisfy the following formula (8).

Hs in the above formula (8) represents the hardness (Hs) at 23 ° C. measured in accordance with JIS K6253.

The rubber composition is preferably formed by blending at least one silica.

According to the present invention, since the rubber physical property after vulcanization is a pneumatic tire having a tread produced using a rubber composition satisfying all the above formulas (1) to (7), low fuel consumption, wet grip performance The steering stability, wear resistance, fatigue resistance and fracture strength can be improved in a well-balanced manner.

The pneumatic tire of the present invention has a tread produced using a rubber composition whose rubber physical properties after vulcanization satisfy all the following formulas (1) to (7).

In the above formulas (1) and (5), tan δ ₁ represents tan δ at 0 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 5%.
Tan δ ₂ in the above formulas (1), (2) and (4) represents tan δ at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%.
E ^* in the above formulas (2) and (3) represents a dynamic elastic modulus (E ^* [MPa]) at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%.
EB in the above formulas (6) and (7) represents tensile elongation (EB [%]) measured according to JIS K6251.
TB in said formula (7) represents the tensile breaking strength (TB [MPa]) measured based on JISK6251.

In this way, by applying a rubber composition having predetermined tan δ, E ^* , EB, TB to the tread after vulcanization, low fuel consumption, wet grip performance, steering stability, wear resistance, A pneumatic tire having improved fatigue characteristics and fracture strength in a well-balanced manner can be provided.

The rubber composition of the present invention has a dynamic elastic modulus (E ^* [MPa]) at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2% in the rubber composition after vulcanization. 3.5 or more and 6.0 or less. That is, the following formula (3) is satisfied.

By having such an appropriate rubber elasticity, both steering stability and wet grip performance can be improved. The E ^* is preferably 3.6 or more. Moreover, 5.8 or less is preferable and 5.5 or less is more preferable.

The rubber composition after vulcanization has a tan δ (tan δ ₂ ) at 30 ° C. of 0.16 or less when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%. That is, the following expression (4) is satisfied.

As a result, excellent fuel efficiency can be obtained. The tan δ ₂ is preferably 0.155 or less, more preferably 0.150 or less, still more preferably 0.145 or less, and particularly preferably 0.140 or less. The lower limit of tan δ ₂ is not particularly limited, and the lower the better.

The rubber composition after vulcanization has a tan δ (tan δ ₁ ) at 0 ° C. of 0.70 or more when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 5%. That is, the following formula (5) is satisfied.

Thereby, the outstanding wet grip performance is obtained. The tan δ ₁ is preferably 0.72 or more, more preferably 0.75 or more, and still more preferably 0.80 or more. The upper limit of tan δ ₁ is not particularly limited, and the larger the better.

The rubber composition after vulcanization further satisfies the following formula (1).

In the above formula (1), tan δ ₁ represents tan δ at 0 ° C. when viscoelasticity measurement was performed with an initial strain of 10% and a dynamic strain of 5%, and tan δ ₂ represents an initial strain of 10% and a dynamic strain of 2%. It represents tan δ at 30 ° C. when viscoelasticity measurement is performed.

When tan δ ₁ and tan δ ₂ satisfy the above formula (1), tan δ ₁ can be increased and tan δ ₂ can be decreased, and both fuel economy and wet grip performance can be improved. The value of the above formula (1) is preferably 4.65 or more, and more preferably 5.0 or more. In addition, the upper limit of the value of the formula (1) is not particularly limited, and the larger the better.

The rubber composition after vulcanization also satisfies the following formula (2).

The formula (2) in ^{E *} is the, represents the initial strain 10%, dynamic elastic modulus at 30 ° C. when the viscoelasticity was measured in a 2% dynamic strain ^{(E *} [MPa]), tan [delta ₂ is It represents tan δ at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%.

When E ^* and tan δ ₂ satisfy the above formula (2), E ^* can be increased and tan δ ₂ can be decreased, and both steering stability and fuel efficiency can be improved. The value of the above formula (2) is preferably 22 or more, more preferably 25 or more, further preferably 30 or more, and particularly preferably 33 or more. In addition, the upper limit of the value of said Formula (2) is not specifically limited, The larger is better.

The rubber composition after vulcanization has a tensile elongation (EB [%]) measured in accordance with JIS K6251 of 600 or more. That is, the following formula (6) is satisfied.

By having a tensile elongation equal to or greater than a specific value, excellent fatigue resistance characteristics can be obtained. The EB is preferably 620 or more, more preferably 640 or more, and still more preferably 650 or more. In addition, the upper limit of EB is not specifically limited, The larger is better.

The rubber composition after vulcanization also satisfies the following formula (7).

EB in the above formula (7) represents the tensile elongation (EB [%]) measured according to JIS K6251, and TB represents the tensile breaking strength (TB [MPa]) measured according to JIS K6251. Represent.

By having a tensile elongation and tensile breaking strength equal to or greater than a specific value, excellent fracture strength can be obtained. The value of the above formula (7) is preferably 13000 or more, and more preferably 15000 or more. In addition, the upper limit of the value of said Formula (7) is not specifically limited, The larger is better.

The rubber composition after vulcanization preferably has a hardness (Hs; type A) at 23 ° C. of 57 or more and 67 or less, measured according to JIS K6253. That is, it is preferable to satisfy the following formula (8).

By having an appropriate hardness, wet grip performance and steering stability can be further improved. If the Hs is less than 57, the workability and the handling stability may be inferior. The Hs is more preferably 66 or less, still more preferably 65 or less, and particularly preferably 61 or less. Moreover, as said Hs, 58 or more are more preferable, and 59 or more are still more preferable.

In the rubber composition after vulcanization, all of the above formulas (1) to (7) are satisfied, and the dynamic elastic modulus at 30 ° C. when the viscoelasticity measurement is performed at a predetermined initial strain of 10% and dynamic strain of 2% and tan δ, initial strain 10%, dynamic strain 5% tan δ when measured at 0 ° C., tensile elongation and tensile strength measured according to JIS K6251 It can be applied by blending, blending a predetermined filler, blending a softener, and in particular, blending a predetermined rubber component and blending a predetermined filler are important.

In general, the tan δ ₁ can be adjusted mainly by changing the type and blending amount of the rubber component, and the tan δ ₂ is mainly used for the type and blending amount of the reinforcing agent (filler). The above E ^* can be adjusted mainly by the amount of the reinforcing agent and the softening agent, and the above EB is mainly adjusted by the amount of the reinforcing agent and the softening agent. In addition, it is known that the TB can be adjusted mainly by the type and amount of the reinforcing agent and rubber component.

The vulcanized rubber composition had a dynamic elastic modulus and tan δ at 30 ° C. when viscoelasticity was measured at an initial strain of 10% and a dynamic strain of 2%, a viscosity at an initial strain of 10% and a dynamic strain of 5%. The tan δ at 0 ° C. at the time of measuring elasticity, the tensile elongation and tensile breaking strength measured in accordance with JIS K6251 and the hardness can be measured by the methods described in Examples below.

The rubber composition in the present invention preferably contains a modified diene rubber having an interaction with silica as a rubber component. Examples of the modified diene rubber include a terminal-modified diene rubber in which at least one terminal of the diene rubber is modified with a compound having a functional group that interacts with silica (modifier), and the main chain has the above-mentioned functionalities. A main chain-modified diene rubber having a group and a main chain terminal-modified diene rubber having the above functional group at the main chain and terminal (for example, the main chain having the above functional group and at least one terminal with the above modifier) Modified main chain terminal-modified diene rubber), terminal modified diene rubber modified with a polyfunctional compound having two or more epoxy groups in the molecule, and introduced with hydroxyl groups or epoxy groups, etc. Can be mentioned. By using such a modified diene rubber, low fuel consumption, wet grip performance, and wear resistance are improved.
The modified diene rubbers may be used alone or in combination of two or more.

Examples of the functional groups include amino groups, amide groups, silyl groups, alkoxysilyl groups, isocyanate groups, imino groups, imidazole groups, urea groups, ether groups, carbonyl groups, oxycarbonyl groups, mercapto groups, sulfide groups, disulfides. Group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group, etc. . These functional groups may have a substituent. Among them, an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), an amino group (preferably a hydrogen atom contained in the amino group has 1 carbon atom) because of particularly high effects of improving fuel economy and wet grip performance. An amino group substituted with an alkyl group of ˜6), an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms), a hydroxyl group, and an epoxy group are preferred.

Examples of the diene rubber into which the functional group is introduced (polymer constituting the skeleton of the modified diene rubber) include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), and styrene butadiene rubber (SBR). Styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and the like. Of these, IR, BR, and SBR are preferable, and BR and SBR are more preferable. In particular, SBR is preferable because it provides a good balance between low fuel consumption and wet grip performance.

The IR is not particularly limited, and for example, IR2200 manufactured by JSR Corporation, IR2200 manufactured by Nippon Zeon Co., Ltd., or the like can be used in the tire industry.

The BR is not particularly limited, for example, BR1220 manufactured by Nippon Zeon Co., Ltd., BR130B manufactured by Ube Industries, Ltd., BR150B, and the like having a high cis content (for example, a cis content of 90% by mass or more), BR containing a syndiotactic polybutadiene crystal such as VCR 412 and VCR 617 manufactured by Ube Industries, Ltd. can be used.

The SBR is not particularly limited, and for example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR) and the like can be used.

When modified SBR is used as the modified diene rubber, SBR modified with a compound represented by the following formula (I) described in JP 2010-111753 A is preferably used as such modified SBR. Can be used. Specifically, for example, E15 manufactured by Asahi Kasei Chemicals Corporation can be used.

In the above formula (I), R ¹¹ , R ¹² and R ¹³ are the same or different and are an alkyl group, an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms), silyloxy Represents a group, an acetal group, a carboxyl group (—COOH), a mercapto group (—SH) or a derivative thereof. R ¹⁴ and R ¹⁵ are the same or different and each represents a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms). n represents an integer (preferably 1-5, more preferably 2-4, still more preferably 3).

R ¹¹ , R ¹² and R ¹³ are preferably at least one of an alkoxy group having 1 to 4 carbon atoms, and R ¹⁴ and R ¹⁵ are a hydrogen atom and an alkyl group having 1 to 4 carbon atoms. Is preferred. Thereby, excellent workability and wear resistance can be obtained.

Specific examples of the compound represented by the above formula (I) include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropyldimethylethoxysilane, 3- Examples include aminopropylmethyldimethoxysilane, 2-dimethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, and 3-dimethylaminopropyltrimethoxysilane. These may be used alone or in combination of two or more.

Examples of the method for modifying styrene butadiene rubber with the compound represented by the above formula (I) (modifier) are described in JP-B-6-53768, JP-B-6-57767, JP-T2003-514078, and the like. A conventionally known method such as a known method can be used. For example, it can be modified by bringing a styrene butadiene rubber into contact with a modifier. Specifically, after a styrene butadiene rubber is prepared by anionic polymerization, a predetermined amount of the modifier is added to the rubber solution to polymerize the styrene butadiene rubber. Examples thereof include a method of reacting a terminal (active terminal) with a modifier.

The vinyl content of the modified SBR is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass or more. If the vinyl content is less than 10% by mass, sufficient wet grip performance may not be obtained. The vinyl content is preferably 90% by mass or less, more preferably 80% by mass or less, and still more preferably 70% by mass or less. If the vinyl content exceeds 90% by mass, the strength may deteriorate.
In addition, in this specification, the vinyl content (1,2-bond butadiene unit amount) of SBR can be measured by an infrared absorption spectrum analysis method.

The styrene content of the modified SBR is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more. If the styrene content is less than 5% by mass, sufficient wet grip performance may not be obtained. The styrene content is preferably 70% by mass or less, more preferably 60% by mass or less, and still more preferably 50% by mass or less. If the styrene content exceeds 70% by mass, the processability may be deteriorated.
In the present specification, the styrene content of SBR is calculated by H ¹ -NMR measurement.

The modified SBR also preferably has a glass transition temperature (Tg) of −45 ° C. or higher, more preferably −40 ° C. or higher, and still more preferably −35 ° C. or higher. The glass transition temperature is preferably 10 ° C. or less, more preferably 5 ° C. or less, and further preferably 0 ° C. or less.
In addition, in this specification, the glass transition temperature of SBR is a value measured by performing differential scanning calorimetry (DSC) according to JIS K7121 under the condition of a heating rate of 10 ° C./min.

The content of the modified diene rubber in 100% by mass of the rubber component is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and particularly preferably 70% by mass or more. If it is less than 40% by mass, wet grip performance may be deteriorated. The content of the modified diene rubber may be 100% by mass, but is preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less. If it exceeds 95% by mass, fuel economy and wear resistance may be reduced.

The rubber component that can be used in the present invention other than the modified diene rubber is not particularly limited, and isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene other than the modified diene rubber. Diene series such as isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), natural rubber (NR), epoxidized natural rubber (ENR) Rubber. These diene rubbers may be used alone or in combination of two or more. Among these, BR, NR, and SBR are preferable, BR and NR are more preferable, and BR is particularly preferable because low fuel consumption, wet grip performance, and wear resistance can be obtained in a well-balanced manner.

The BR is not particularly limited. For example, BR1220 manufactured by Nippon Zeon Co., Ltd., BR130B manufactured by Ube Industries, Ltd., BR150B having high cis content such as BR150B, VCR412 manufactured by Ube Industries, Ltd., VCR617, etc. BR containing a syndiotactic polybutadiene crystal can be used. Among them, the cis content of BR is preferably 90% by mass or more, and more preferably 95% by mass or more, because of low fuel consumption and good wear resistance.
The cis content of BR can be measured by infrared absorption spectrum analysis.

When BR is blended as a rubber component, the content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. The content is preferably 60% by mass or less, more preferably 40% by mass or less. By setting the content within the above range, the wear resistance can be dramatically improved.

The NR is not particularly limited and, for example, SIR20, RSS # 3, TSR20, deproteinized natural rubber (DPNR), high-purity natural rubber (HPNR), etc., which are common in the tire industry can be used.

When NR is blended as the rubber component, the content of NR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more. The content is preferably 60% by mass or less, more preferably 40% by mass or less. By setting the content within the above range, the wear resistance can be dramatically improved.

The SBR is not particularly limited, and for example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR), and the like can be used.

When SBR is blended as the rubber component, the content of SBR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 20% by mass or more. The content is preferably 60% by mass or less, more preferably 40% by mass or less. By setting the content within the above range, the wear resistance can be dramatically improved.

The rubber composition in the present invention is preferably formed by blending at least one kind of silica. By blending silica together with the modified diene rubber, excellent fuel economy and rubber strength (fatigue resistance, fracture resistance) can be obtained. The silica is not particularly limited, and examples thereof include dry process silica (anhydrous silicic acid), wet process silica (hydrous silicic acid), and the like, but wet process silica is preferable because of its large number of silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 40 m ² / g or more, and more preferably 50 m ² / g or more. If it is less than 40 m < ² > / g, there exists a tendency for the fracture strength after vulcanization to fall. The _N 2 SA of the silica is preferably 250 meters ² / g or less, more preferably 200m ² / g. When it exceeds 250 m ² / g, fuel economy and rubber processability tend to be lowered.
In addition, the nitrogen adsorption specific surface area of a silica is a value measured by BET method according to ASTM D3037-93.

The content of silica is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and still more preferably 45 parts by mass or more with respect to 100 parts by mass of the rubber component. When the amount is less than 20 parts by mass, there is a tendency that a sufficient effect due to silica blending cannot be obtained. The content is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and still more preferably 100 parts by mass or less. When the amount exceeds 150 parts by mass, it is difficult to disperse silica in rubber, and the processability of rubber tends to deteriorate.

When the rubber composition in this invention contains a silica, it is preferable that a silane coupling agent is included with a silica.
As the silane coupling agent, any silane coupling agent conventionally used in combination with silica can be used. For example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) ) Tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (4-trimethoxysilylbutyl) tetra Sulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-triethoxysilylbutyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, Screw (2- Rimethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) ) Disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl Tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilyl ester Ru-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxy Sulfide series such as silylpropyl methacrylate monosulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-octanoylthio-1-propyltri Mercapto type such as ethoxysilane, vinyl type such as vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-a Amino compounds such as minopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- Glycidoxy compounds such as glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, etc. Examples include nitro-based, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane. Product names include Si69, Si75, Si363 (Degussa), NXT, NXT-LV, NXTULV, NXT-Z (Momentive). Of these, mercapto-based silane coupling agents are preferred because good fuel economy can be obtained.
These silane coupling agents may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the silane coupling agent when the silane coupling agent is blended with the rubber composition in the present invention is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass with respect to 100 parts by mass of silica. Part or more, more preferably 2.5 parts by weight or more, and particularly preferably 5 parts by weight or more. If it is less than 0.5 parts by mass, it may be difficult to disperse silica well. The content is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and still more preferably 15 parts by mass or less. Even if a silane coupling agent exceeding 25 parts by mass is blended, the effect of improving the dispersion of silica cannot be obtained, and the cost tends to increase unnecessarily. In addition, the scorch time is shortened, and the workability during kneading and extrusion tends to decrease.

In addition to silica, fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide and mica may be blended with the rubber composition in the present invention. Especially, it is preferable to mix | blend aluminum hydroxide at the point which can achieve low fuel-consumption property and wet grip performance on a high level. That is, in the present invention, it is preferable to use silica and aluminum hydroxide in combination. As a result, while improving fuel economy and wet grip performance in a well-balanced manner, it is possible to improve wear resistance, steering stability, and rubber strength (fatigue resistance and fracture resistance).
In this specification, aluminum hydroxide means Al (OH) ₃ or Al ₂ O ₃ .3H ₂ O.
These fillers may be used individually by 1 type, and may use 2 or more types together.

The average particle diameter of aluminum hydroxide is preferably 10 μm or less, more preferably 5 μm or less, and still more preferably 3 μm or less. If the thickness exceeds 10 μm, good wet grip performance may not be obtained. The average particle diameter is preferably 0.05 μm or more, more preferably 0.1 μm or more. When it is less than 0.05 μm, dispersion becomes difficult and wet grip performance may be deteriorated.

In addition, the average particle diameter of aluminum hydroxide is measured using a transmission type or a scanning electron microscope. The average particle diameter means a major axis, and the major axis is the longest length when the aluminum hydroxide powder is projected onto the projection plane while variously changing the direction of the aluminum hydroxide powder relative to the projection plane.

When aluminum hydroxide is blended with the rubber composition in the present invention, the content of aluminum hydroxide is preferably 1 part by mass or more, more preferably 5 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 1 part by mass, the effect of improving wet grip performance may be small. The content of aluminum hydroxide is preferably 75 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 30 parts by mass or less, and particularly preferably 20 parts by mass or less. If it exceeds 75 parts by mass, poor dispersion may occur and the wear resistance may deteriorate.

The mass ratio of aluminum hydroxide to silica (aluminum hydroxide (parts by mass) / silica (parts by mass)) when aluminum hydroxide is blended with the rubber composition in the present invention is less than 0.3. Preferably, 0.28 or less is more preferable, and 0.25 or less is more preferable. When the mass ratio of aluminum hydroxide and silica is within such a range, the fuel economy and wear resistance can be improved in a particularly well-balanced manner. The lower limit of the mass ratio of aluminum hydroxide to silica (aluminum hydroxide (mass part) / silica (mass part)) is not particularly limited, but is preferably 0.01 or more, more preferably 0.10 or more, and 0 .15 or more is more preferable.

You may mix | blend carbon black with the rubber composition in this invention.
Thereby, rubber strength can be improved. Examples of carbon black that can be used include GPF, FEF, HAF, ISAF, and SAF, but are not particularly limited. These carbon blacks may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 10 m ² / g or more, more preferably 20 m ² / g or more, and further preferably 70 m ² / g or more. The N ₂ SA is preferably 200 m ² / g or less, more preferably 150 m ² / g or less, and still more preferably 140 m ² / g or less. If it is less than 10 m ² / g, a sufficient reinforcing effect may not be obtained, and if it exceeds 200 m ² / g, fuel economy tends to be reduced.
In addition, the nitrogen adsorption specific surface area of carbon black is calculated | required by A method of JISK6217.

When carbon black is blended with the rubber composition in the present invention, the content of carbon black is preferably 1 part by mass or more and more preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. Moreover, 20 mass parts or less are preferable, and 15 mass parts or less are more preferable. By adjusting the blending amount of carbon black within the above range, weather resistance, antistatic properties, and rubber strength can be improved. If the amount is less than 1 part by mass, sufficient reinforcing properties tend not to be obtained. Moreover, when it exceeds 20 mass parts, there exists a possibility that it may be inferior to low fuel consumption.

In addition to the above components, the rubber composition in the present invention includes compounding agents generally used in the tire industry, for example, softeners such as oil, aromatic petroleum resins, waxes, various anti-aging agents, stearic acid Zinc oxide, processing aids, vulcanizing agents such as sulfur, vulcanization accelerators, and the like may be appropriately blended.

Although it does not specifically limit as a softener which can be used by this invention, For example, aromatic mineral oil (viscosity specific gravity constant (VGC value) 0.900-1.049), naphthenic mineral oil ( VGC values 0.850 to 0.899) and paraffinic mineral oils (VGC values 0.790 to 0.849). The polycyclic aromatic content of the oil is preferably less than 3% by mass, more preferably less than 1% by mass. The polycyclic aromatic content is measured according to the British Petroleum Institute 346/92 method. The aromatic compound content (CA) of the oil is preferably 20% by mass or more.
As the softening agent, a liquid polymer (liquid diene polymer), a liquid resin, vegetable oil, an ester plasticizer, or the like can be used.
These softeners may be used alone or in combination of two or more.

The content of the softening agent in the case where the softening agent is blended with the rubber composition in the present invention is 1 part by mass or more with respect to 100 parts by mass of the rubber component because the effect of the present invention can be more suitably obtained. Preferably, 5 parts by mass or more is more preferable, and 10 parts by mass or more is still more preferable. Further, the content is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 30 parts by mass or less with respect to 100 parts by mass of the rubber component.

In this invention, it is preferable to mix | blend aromatic petroleum resin from the reason that the effect of this invention is acquired suitably. Aromatic petroleum resins include phenolic resins, coumarone indene resins, styrene resins, rosin resins, DCPD resins, and the like. These aromatic petroleum resins may be used alone or in combination of two or more.
Among these, a styrene resin is preferable because an effect of the present invention can be more suitably obtained, and an aromatic vinyl polymer obtained by polymerizing α-methylstyrene and / or styrene is more preferable.

In the aromatic vinyl polymer, styrene and α-methylstyrene are used as the aromatic vinyl monomer (unit), and either a homopolymer of each monomer or a copolymer of both monomers is used. Good. The aromatic vinyl polymer is preferably an α-methylstyrene homopolymer or a copolymer of α-methylstyrene and styrene because it is economical, easy to process, and excellent in wet grip performance.

The softening point of the aromatic petroleum resin is preferably 70 ° C. or higher, more preferably 80 ° C. or higher. If it is less than 70 ° C., the wet grip performance tends to deteriorate. The softening point is preferably 140 ° C. or lower, more preferably 120 ° C. or lower, and still more preferably 100 ° C. or lower. When it exceeds 140 ° C., wear resistance and wet grip performance tend to deteriorate.
The softening point of the aromatic petroleum resin is the temperature at which the sphere descends when the softening point specified in JIS K6220-1: 2001 is measured with a ring and ball softening point measuring device.

The weight average molecular weight (Mw) of the aromatic petroleum resin is preferably 500 or more, more preferably 800 or more. If it is less than 500, there is a tendency that a sufficient improvement effect of wet grip performance cannot be obtained. The weight average molecular weight of the aromatic petroleum resin is preferably 3000 or less, more preferably 2000 or less. If it exceeds 3000, the wear resistance tends to deteriorate.
In addition, the weight average molecular weight (Mw) of aromatic petroleum resin is gel permeation chromatograph (GPC) (GPC-8000 series made by Tosoh Corporation, detector: differential refractometer, column: Tosoh Corporation ) Manufactured by TSKGEL SUPERMALTPORE HZ-M), based on standard polystyrene conversion.

When the aromatic petroleum resin is blended with the rubber composition in the present invention, the content of the aromatic petroleum resin is preferably 2 parts by mass or more, more preferably 5 parts by mass with respect to 100 parts by mass of the rubber component. As mentioned above, More preferably, it is 7 mass parts or more. If it is less than 2 parts by mass, the effect of improving wet grip performance may not be sufficiently obtained. Moreover, this content becomes like this. Preferably it is 25 mass parts or less, More preferably, it is 20 mass parts or less. If it exceeds 25 parts by mass, sufficient wet grip performance may not be obtained. In addition, the temperature dependency increases, and the performance change with respect to the temperature change increases, and for example, the thermal sag performance tends to decrease.

The anti-aging agent that can be used in the present invention is not particularly limited. Polyphenol-based), thiobisphenol-based, benzimidazole-based, thiourea-based, phosphorous acid-based, and organic thioacid-based anti-aging agents.

Examples of the naphthylamine anti-aging agent include phenyl-α-naphthylamine, phenyl-β-naphthylamine, aldol-α-trimethyl1,2-naphthylamine and the like.

Examples of the quinoline antioxidant include 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline.

Examples of the diphenylamine antioxidant include p-isopropoxydiphenylamine, p- (p-toluenesulfonylamide) -diphenylamine, N, N-diphenylethylenediamine, octylated diphenylamine and the like.

Examples of p-phenylenediamine-based antioxidants include N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, and N, N ′. -Diphenyl-p-phenylenediamine, N, N'-di-2-naphthyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N, N'-bis (1-methylheptyl) -P-phenylenediamine, N, N'-bis (1,4-dimethylpentyl) -p-phenylenediamine, N, N'-bis (1-ethyl-3-methylpentyl) -p-phenylenediamine, N- 4-methyl-2-pentyl-N′-phenyl-p-phenylenediamine, N, N′-diaryl-p-phenylenediamine, hindered dia Lumpur -p- phenylenediamine, phenyl hexyl -p- phenylenediamine, and the like phenyloctyl -p- phenylenediamine.

Examples of the hydroquinone derivative antioxidant include 2,5-di- (tert-amyl) hydroquinone and 2,5-di-tert-butylhydroquinone.

With respect to the phenolic anti-aging agent, the monophenolic anti-aging agent includes 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6- Di-tert-butylphenol, 1-oxy-3-methyl-4-isopropylbenzene, butylhydroxyanisole, 2,4-dimethyl-6-tert-butylphenol, n-octadecyl-3- (4′-hydroxy-3 ′, 5'-di-tert-butylphenyl) propionate, styrenated phenol and the like. Examples of the bisphenol-based, trisphenol-based, and polyphenol-based antiaging agents include 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl- 6-tert-butylphenol), 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenol), 1,1′-bis- (4-hydroxyphenyl) -cyclohexane, tetrakis- [methylene-3 -(3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane and the like.

Examples of the thiobisphenol antioxidant include 4,4′-thiobis- (6-tert-butyl-3-methylphenol) and 2,2′-thiobis- (6-tert-butyl-4-methylphenol). Can be mentioned. Examples of the benzimidazole antioxidant include 2-mercaptomethylbenzimidazole. Examples of the thiourea antioxidant include tributylthiourea. Examples of the phosphite antioxidant include tris (nonylphenyl) phosphite. Examples of the organic thioacid-based anti-aging agent include dilauryl thiodipropionate. These anti-aging agents may be used alone or in combination of two or more.

Especially, since the effect of this invention is acquired more suitably, it is preferable to use together a quinoline type | system | group antioxidant and p-phenylenediamine type | system | group antioxidant. In addition, the content of the anti-aging agent when blending the anti-aging agent with the rubber composition in the present invention (the total content when two or more anti-aging agents are blended) is 100 parts by mass of the rubber component. The amount is preferably 1 to 10 parts by mass, and more preferably 3 to 7 parts by mass with respect to parts.

The rubber composition in the present invention preferably contains zinc oxide. Thereby, vulcanization is smooth and rigidity and physical properties are obtained. Zinc oxide is not particularly limited, and zinc oxide conventionally used in the rubber industry (eg, silver candy R manufactured by Toho Zinc Co., Ltd., zinc oxide manufactured by Mitsui Metal Mining Co., Ltd.) or an average particle size of 200 nm or less. Fine particle zinc oxide (such as Zinccock Super F-2 manufactured by Hakusuitec Co., Ltd.). These zinc oxides may be used alone or in combination of two or more.

When blending zinc oxide with the rubber composition in the present invention, the blending amount of zinc oxide is preferably 1.0 parts by mass or more, more preferably 1.5 parts by mass or more with respect to 100 parts by mass of the rubber component. is there. If it is less than 1.0 part by mass, sufficient hardness (Hs) may not be obtained due to vulcanization reversion. The blending amount is preferably 3.7 parts by mass or less, more preferably 3.0 parts by mass or less. If it exceeds 3.7 parts by mass, the breaking strength tends to decrease.

The vulcanizing agent is not particularly limited, but sulfur, alkylphenol / sulfur chloride condensate and the like can be suitably used, and sulfur is preferred.
These vulcanizing agents may be used alone or in combination of two or more.

The content of the vulcanizing agent is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more with respect to 100 parts by mass of the rubber component. The content of the vulcanizing agent is preferably 7 parts by mass or less, more preferably 5 parts by mass or less. By adjusting within the above range, the effect of the present invention can be obtained more suitably.

Examples of the vulcanization accelerator include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, and xanthate vulcanization accelerators. Etc. These vulcanization accelerators may be used alone or in combination of two or more. Among them, sulfenamide-based and guanidine-based vulcanization accelerators are preferable because the effects of the present invention can be more suitably obtained, and the combined use of a sulfenamide-based vulcanization accelerator and a guanidine-based vulcanization accelerator is more preferable. preferable.

Examples of the sulfenamide vulcanization accelerator include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N, N -Dicyclohexyl-2-benzothiazolylsulfenamide (DCBS) and the like.

Examples of the guanidine vulcanization accelerator include diphenyl guanidine, diortolyl guanidine, orthotolyl biguanidine and the like.

The content of the vulcanization accelerator (when two or more vulcanization accelerators are blended, the total content thereof) is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the rubber component. Preferably it is 0.5 mass part or more, More preferably, it is 1 mass part or more. The content of the vulcanization accelerator is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and still more preferably 6 parts by mass or less. By adjusting within the above range, the effect of the present invention can be obtained more suitably.

As a method for producing the rubber composition in the present invention, a known method can be used. For example, the above components are kneaded using a rubber kneading apparatus such as an open roll, a Banbury mixer, and then vulcanized. Can be manufactured.

The pneumatic tire of the present invention is produced by a usual method using the rubber composition. That is, the rubber composition containing the above components is extruded in accordance with the shape of the tread at an unvulcanized stage and molded together with other tire members on a tire molding machine by a normal method. Form a vulcanized tire. The unvulcanized tire is heated and pressurized in a vulcanizer to obtain a tire.

The pneumatic tire of the present invention is suitably used as a passenger tire, truck / bus tire, motorcycle tire, competition tire, and the like, and particularly preferably used as a passenger tire.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.
The various chemicals used in the examples are described below.
SBR1: Modified SBR manufactured by Sumitomo Chemical Co., Ltd. (modified S-SBR (compound represented by formula (I) (R ¹¹ = methoxy group, R ¹² = methoxy group, R ¹³ = methoxy group, R ¹⁴ = ethyl group) , R ¹⁵ = ethyl group, n = 3) S-SBR whose terminal is modified by styrene, styrene content: 25% by mass, vinyl content: 57% by mass, Tg: −25 ° C.))
SBR2: Nipol 1502 (Non-modified SBR, styrene content: 24.5% by mass, vinyl content: 15.1% by mass, Tg: −52 ° C.) manufactured by Nippon Zeon Co., Ltd.
BR: Ubepol BR150B manufactured by Ube Industries, Ltd. (cis content: 96% by mass)
Silica: Ultrasil VN3 (N ₂ SA: 175 m ² / g) manufactured by Evonik Degussa
Carbon black: Dia Black N220 (ISAF, N ₂ SA: 114 m ² / g) manufactured by Mitsubishi Chemical Corporation
Aluminum hydroxide: Apalal 200SM (average particle size: 0.6 μm) manufactured by Nabaltec
Silane coupling agent: NXT (3-octanoylthio-1-propyltriethoxysilane) manufactured by Momentive
Oil: Japan Energy X-140
Resin: SYLVARES SA85 manufactured by Arizona Chemical Co. (Copolymer of α-methylstyrene and styrene (aromatic vinyl polymer), softening point: 85 ° C., Mw: 1000)
Wax: Sunnock N manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Antiaging agent 1: Nouchi 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Anti-aging agent 2: NOUCL 224 (2,2,4-trimethyl-1,2-dihydroquinoline polymer) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Stearic acid: NOF Co., Ltd.
Zinc oxide: Made by Mitsui Mining & Smelting Co., Ltd. Zinc Hua 2 kinds sulfur: Tsurumi Chemical Co., Ltd. Powder sulfur vulcanization accelerator 1: Ouchi Shinsei Chemical Co., Ltd. Noxeller NS (N-tert-butyl-2) -Benzothiazolylsulfenamide)
Vulcanization accelerator 2: Sumocinol D (diphenylguanidine) manufactured by Sumitomo Chemical Co., Ltd.

(Examples and Comparative Examples)
In accordance with the formulation shown in Table 1, materials other than sulfur and a vulcanization accelerator were kneaded for 5 minutes at 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. Obtained. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 5 minutes under the condition of 80 ° C. using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was press vulcanized with a 0.5 mm thick mold at 150 ° C. for 30 minutes to obtain a vulcanized rubber composition. Further, the obtained unvulcanized rubber composition is molded into a tread shape, bonded together with other tire members on a tire molding machine, and vulcanized at 150 ° C. for 30 minutes for testing. A tire (size: 195 / 65R15) was produced.
The following evaluation was performed about the obtained vulcanized rubber composition and the tire for a test. The results are shown in Table 1.

(Viscoelasticity measurement)
Using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.), temperature 0 ° C., frequency 10 Hz, initial strain 10% and dynamic strain 5%, temperature 30 ° C., frequency 10 Hz, initial strain 10% and dynamic strain Under the condition of 2%, the dynamic elastic modulus (E ^* [MPa]) and loss tangent (tan δ) of the vulcanized rubber composition were measured. The values of the following formulas (1) to (5) were calculated from the obtained values.

In the above formulas (1) and (5), tan δ ₁ represents tan δ at 0 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 5%. In the formulas (1), (2), and (4), tan δ ₂ represents tan δ at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%. E ^* in the formulas (2) and (3) represents a dynamic elastic modulus (E ^* [MPa]) at 30 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 2%.

(Tensile test)
In accordance with JIS K6251 “How to determine tensile properties of vulcanized rubber and thermoplastic rubber”, a tensile test was conducted using a No. 3 dumbbell-shaped test piece made of vulcanized rubber composition. Elongation (tensile elongation; EB [%]) and tensile strength at break (tensile breaking strength: TB [MPa]) were measured. The values of the following formulas (6) to (7) were calculated from the obtained values. It shows that it is excellent in the fatigue-resistant characteristic and fracture strength, so that the value of Formula (6)-(7) is large.

EB in the above formulas (6) and (7) represents tensile elongation (EB [%]) measured according to JIS K6251. TB in the formula (7) represents the tensile strength at break (TB [MPa]) measured according to JIS K6251.

(hardness)
According to JIS K6253 “Method for testing hardness of vulcanized rubber and thermoplastic rubber”, the hardness (Hs) at 23 ° C. of each rubber test piece (vulcanized rubber composition) was measured with a type A durometer.

(Low fuel consumption)
Using a rolling resistance tester, the rolling resistance when a test tire was run at a rim (15 × 6JJ), internal pressure (230 kPa), load (3.43 kN), speed (80 km / h) was measured and compared. It was displayed as an index when Example 1 was taken as 100. A larger index is better (low fuel consumption).

(Wet grip performance)
Each test tire was mounted on all wheels of a vehicle (domestic FF2000cc), and a braking distance from an initial speed of 100 km / h was determined on a wet asphalt road surface. The result is expressed as an index. The larger the number, the better the wet skid performance (wet grip performance). The index was calculated by the following formula.
Wet skid performance = (braking distance of comparative example 1) ÷ (braking distance of each formulation) × 100

(Maneuvering stability)
Each test tire was mounted on all wheels of a vehicle (domestic FF2000cc) and the vehicle was run on the test course, and the steering stability was evaluated by sensory evaluation of the driver when meandering. Furthermore, the steering stability immediately after the start of the test and 30 minutes after the start was evaluated. The above evaluations were comprehensively evaluated with the steering stability of Comparative Example 1 as 100 points. The larger the value, the better the steering stability.

(Abrasion resistance)
Each test tire was mounted on all wheels of a vehicle (domestic FF2000cc) and traveled on an actual vehicle, and the change in pattern groove depth after traveling 35,000 km was determined. The results are expressed as an index when Comparative Example 1 is taken as 100. The higher the index, the better the wear resistance.

The tire of the example in which the rubber composition having predetermined tan δ, E ^* , EB, and TB in the state after vulcanization is applied to the tread has low fuel consumption, wet grip performance, driving stability, wear resistance, fatigue resistance It was revealed that the characteristics and fracture strength were improved in a well-balanced manner.
In particular, in an example in which a predetermined SBR was used and silica and aluminum hydroxide were used in a predetermined ratio, desired performance was obtained.
On the other hand, when these components were not used, predetermined physical properties could not be imparted after vulcanization and the performance was inferior.

Claims (5)

A pneumatic tire having a tread produced using a rubber composition,
Rubber properties after vulcanization of the rubber composition satisfy all the following formulas (1) to (7),
A pneumatic tire in which the rubber composition contains aluminum hydroxide.

(Tan δ ₁ in the formulas (1) and (5) represents tan δ at 0 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 5%. The formulas (1), (2) and ( 4) tan [delta ₂ in the initial strain of 10%. formula representing the tan [delta at 30 ° C. when the viscoelasticity was measured in a 2% dynamic strain (2) and (3) of the ^{E *} is, initial strain 10 %, Dynamic elastic modulus (E ^* [MPa]) at 30 ° C. when viscoelasticity measurement is performed with 2% dynamic strain, EB in the formulas (6) and (7) is based on JIS K6251. (The tensile elongation (EB [%]) measured in the above formula is used. TB in the formula (7) represents the tensile breaking strength (TB [MPa]) measured in accordance with JIS K6251.) A pneumatic tire having a tread produced using a rubber composition,
Rubber properties after vulcanization of the rubber composition satisfy all the following formulas (1) to (7),
A pneumatic tire in which the rubber composition contains an aromatic petroleum resin.

(Tan δ ₁ in the formulas (1) and (5) represents tan δ at 0 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 5%. The formulas (1), (2) and ( 4) tan [delta ₂ in the initial strain of 10%. formula representing the tan [delta at 30 ° C. when the viscoelasticity was measured in a 2% dynamic strain (2) and (3) of the ^{E *} is, initial strain 10 %, Dynamic elastic modulus (E ^* [MPa]) at 30 ° C. when viscoelasticity measurement is performed with 2% dynamic strain, EB in the formulas (6) and (7) is based on JIS K6251. (The tensile elongation (EB [%]) measured in the above formula is used. TB in the formula (7) represents the tensile breaking strength (TB [MPa]) measured in accordance with JIS K6251.) A pneumatic tire having a tread produced using a rubber composition,
Rubber properties after vulcanization of the rubber composition satisfy all the following formulas (1) to (7),
A pneumatic tire in which the rubber composition contains aluminum hydroxide and an aromatic petroleum resin.

(Tan δ ₁ in the formulas (1) and (5) represents tan δ at 0 ° C. when viscoelasticity measurement is performed with an initial strain of 10% and a dynamic strain of 5%. The formulas (1), (2) and ( 4) tan [delta ₂ in the initial strain of 10%. formula representing the tan [delta at 30 ° C. when the viscoelasticity was measured in a 2% dynamic strain (2) and (3) of the ^{E *} is, initial strain 10 %, Dynamic elastic modulus (E ^* [MPa]) at 30 ° C. when viscoelasticity measurement is performed with 2% dynamic strain, EB in the formulas (6) and (7) is based on JIS K6251. (The tensile elongation (EB [%]) measured in the above formula is used. TB in the formula (7) represents the tensile breaking strength (TB [MPa]) measured in accordance with JIS K6251.) The pneumatic tire according to any one of claims 1 to 3, wherein rubber properties after vulcanization of the rubber composition further satisfy the following formula (8).

(Hs in Formula (8) represents the hardness (Hs) at 23 ° C. measured in accordance with JIS K6253.) The pneumatic tire according to any one of claims 1 to 4, wherein the rubber composition is formed by blending at least one kind of silica.