JP2017193622A - tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire excellent in grip performance without deteriorating in abrasion resistance and low fuel economy.SOLUTION: There are provided a tire having a tread composed of a rubber composition containing a hydroxide of a group 13 element excluding aluminum hydroxide and a coupling agent; and a tire which is composed of a rubber composition containing a hydroxide of a group 13 element and a coupling agent, and has rubber hardness of -3 to +3 with respect to a reference rubber composition containing no hydroxide of the group 13 element and elongation at break of 103% or more.SELECTED DRAWING: None

Description

  The present invention relates to a pneumatic tire having a tread composed of a predetermined rubber composition.

  In recent years, due to increasing interest in environmental issues, there has been a strong demand for fuel efficiency reduction for automobiles, and tires that reduce heat generation by reducing rolling resistance of tires are being developed. Among the tire members, particularly for a tread having a high occupation ratio in the tire, excellent low fuel consumption is required. In addition, grip performance, wear resistance, and the like are also required as the original performance of the tread.

  In general, it is effective to reduce the energy loss of the rubber composition in order to improve fuel efficiency. On the other hand, in order to improve the grip performance, methods such as increasing the amount of silica, increasing the ratio of a softener such as oil, and blending a resin to increase the glass transition temperature of the rubber composition have been made. According to the method, energy loss increases and fuel efficiency deteriorates. In other words, fuel efficiency and grip performance are contradictory, and it is difficult to achieve both. There is also a method to improve grip performance by increasing the elongation of rubber by adding inorganic fillers of large particle size such as calcium carbonate and magnesium oxide, and increasing the followability with the road surface without increasing energy loss. Although being studied, these large-diameter inorganic fillers have a problem of insufficient wear resistance due to poor reinforcement. Thus, it has been difficult to improve the fuel economy, grip performance and wear resistance in a well-balanced manner.

  Patent Document 1 improves the fuel economy and wet grip performance without degrading workability and wear resistance by blending aluminum hydroxide having specific properties with a rubber component having a low glass transition temperature. A tread rubber composition is described. Further, it is described that the reinforcing property of aluminum hydroxide is enhanced by blending a silane coupling agent. However, there is room for improvement in terms of achieving both wear resistance, low fuel consumption, and grip performance.

JP 2001-181447 A

  An object of the present invention is to provide a tire excellent in grip performance while maintaining wear resistance and low fuel consumption.

1st invention of this invention is related with a tire provided with the tread comprised with the hydroxide of the group 13 element except aluminum hydroxide, and the rubber composition containing a coupling agent.

  A second invention of the present invention is a rubber composition containing a hydroxide of a group 13 element and a coupling agent, and with respect to a reference rubber composition not containing a hydroxide of a group 13 element, The present invention relates to a tire including a tread composed of a rubber composition having a rubber hardness of −3 to +3 and an elongation at break of 103% or more.

<First invention>
A tire according to a first aspect of the present invention includes a tread composed of a rubber composition containing a hydroxide of a group 13 element excluding aluminum hydroxide and a coupling agent with respect to a diene rubber component. To do.

  The diene rubber component is not particularly limited. For example, natural rubber (NR), epoxidized natural rubber (ENR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and the like can be used in the rubber industry. These rubber components may be used alone or in combination of two or more. The rubber component may be appropriately selected according to the required performance, and for example, NR, ENR, SBR, and BR are preferable.

  The NR is not particularly limited, and those generally used in the rubber industry such as SIR20, RSS # 3, TSR20, and the like can be used. The ENR is not particularly limited, and commercially available products such as ENR25 and ENR50 manufactured by MRB (Malaysia) may be used, or NR may be epoxidized.

  The content in 100% by mass of the rubber component in the case of containing NR and / or ENR is preferably 5% by mass or more, more preferably 10% by mass or more, because sufficient strength can be obtained. Further, in order to improve crack growth resistance, ozone resistance, wear resistance, etc., it is preferable to use in combination with other rubber components, so the content of NR and / or ENR is preferably 90% by mass or less, 70 mass% or less is more preferable.

  The SBR is not particularly limited, and unmodified solution polymerization SBR (S-SBR), unmodified emulsion polymerization SBR (E-SBR), and these modified SBRs (modified S-SBR, modified E-SBR), and the like Among them, modified SBR is preferable because it has a high effect of improving grip performance, low fuel consumption, and steering stability.

  As the modified SBR, those coupled with tin, a silicon compound or the like are preferable. As a coupling method of the modified SBR, for example, an alkali metal (such as Li) or an alkaline earth metal (such as Mg) at the molecular chain terminal of the modified SBR is reacted with tin halide or silicon halide according to a conventional method. The method etc. are mentioned.

  The modified SBR is preferably a copolymer of styrene and butadiene having a primary amino group or an alkoxysilyl group. The primary amino group may be bonded to any of the polymerization initiation terminal, the polymerization termination terminal, the polymer main chain, and the side chain, but the energy loss characteristic is improved by suppressing the energy loss from the polymer terminal. From the viewpoint of obtaining, it is preferably introduced at the polymerization initiation terminal or the polymerization termination terminal.

（化学式（１）中、Ｒ¹、Ｒ²およびＲ³は、同一もしくは異なって、アルキル基、アルコキシ基、シリルオキシ基、アセタール基、カルボキシル基、メルカプト基（−ＳＨ）またはこれらの誘導体を表す。Ｒ⁴およびＲ⁵は、同一もしくは異なって、水素原子またはアルキル基を表す。ｍは整数を表す。） Among these modified SBRs, it is easy to control the molecular weight of the polymer, can reduce the low molecular weight component that increases the rolling resistance, and further strengthens the bond between the reinforcing agent and the polymer chain, grip performance, low fuel consumption, and steering stability Modified S-SBR in which the polymerization terminal (active terminal) of solution-polymerized styrene butadiene rubber (S-SBR) is modified with a nitrogen-containing compound such as the compound represented by the following chemical formula (1) (Modified SBR described in JP 2010-111753 A) is preferably used.

(In the chemical formula (1), R ¹ , R ² and R ³ are the same or different and each represents an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group, a mercapto group (—SH) or a derivative thereof. R ⁴ and R ⁵ are the same or different and each represents a hydrogen atom or an alkyl group, and m represents an integer.

The alkyl group for R ¹ , R ² and R ³ is preferably an alkyl group having 1 to 4 carbon atoms.

The alkoxy group of R ¹ , R ² and R ³ is preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkoxy group having 1 to 4 carbon atoms.

The acetal group of R ¹ , R ² and R ³ is preferably an acetal group having 1 to 8 carbon atoms.

The alkyl group for R ⁴ and R ⁵ is preferably an alkyl group having 1 to 4 carbon atoms.

  m represents an integer, preferably 1 to 5, more preferably 2 to 4, and still more preferably 3.

Examples of the compound represented by the chemical formula (1) include 3-aminopropyltrimethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 2-dimethylaminoethyltrimethoxysilane, 3-diethylaminopropyltri Examples include methoxysilane and 3-dimethylaminopropyltrimethoxysilane. These may be used alone or in combination of two or more. Among them, as the compound represented by the chemical formula (1) used for the modified SBR, R ¹ , R ² and R ³ are alkoxy groups because of excellent grip performance and low fuel consumption, and R ^A compound in which ⁴ and R ⁵ are hydrogen atoms (3-aminopropyltrimethoxysilane) is preferred.

  As a method for modifying SBR with a compound (modifier) represented by the chemical formula (1), it is described in JP-B-6-53768, JP-B-6-57767, JP-T2003-514078, and the like. A conventionally known method such as a method can be used. For example, SBR may be brought into contact with a modifying agent. After SBR is synthesized by anionic polymerization, a predetermined amount of a modifying agent is added to the polymer rubber solution, and the polymerization terminal (active terminal) of SBR and the modifying agent are added. And a method of reacting by adding a denaturing agent to the BR solution.

The styrene content of SBR is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more from the viewpoint of grip performance. Further, the styrene content of SBR is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less, because the contact area with the road surface increases and high grip performance is obtained. . In addition, the styrene content of SBR in the present specification is a value calculated by ¹ H-NMR measurement.

The vinyl bond amount of SBR is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 15 mol% or more from the viewpoint of securing grip performance. The vinyl bond amount of SBR is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less, from the viewpoints of wear resistance and fuel efficiency. In addition, the vinyl bond amount of SBR in this specification shows the vinyl bond amount of a butadiene part, and is a value computed by < ¹ > H-NMR measurement.

  In the case of containing SBR, the content in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 50% by mass or more, further preferably 70% by mass or more, and 100% by mass from the viewpoint of grip performance. Particularly preferred. Further, the upper limit of the SBR content is not particularly limited, but when used in combination with other rubber components, it is preferably 90% by mass or less. In addition, when SBR is an oil-extended product to which oil is added, the content of SBR indicates the content of SBR (rubber solid content) excluding the oil content.

  The BR is not particularly limited, and unmodified butadiene rubber such as high cis 1,4-polybutadiene rubber (high cis BR), butadiene rubber containing 1,2-syndiotactic polybutadiene crystals (SPB-containing BR); modified butadiene rubber ( Modified BR) and the like.

  The high cis BR is a butadiene rubber having a cis 1,4 bond content of 90% by mass or more. Examples of such commercially available high-sis BR include BR1220 manufactured by Nippon Zeon Co., Ltd., UBEPOL BR130B and BR150B manufactured by Ube Industries, Ltd.

  The SPB-containing BR is preferably not that in which 1,2-syndiotactic polybutadiene crystals are simply dispersed in BR but is dispersed after being chemically bonded to BR. Examples of such commercially available SPB-containing BR include VCR303, VCR412, and VCR617 manufactured by Ube Industries.

  The modified BR is obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound, and the modified BR molecule has an end bonded with a tin-carbon bond; Examples thereof include those modified with a nitrogen-containing compound such as the compound represented by the chemical formula (1).

  The method for modifying BR by the compound represented by the chemical formula (1) (modifier) is the same as the method for modifying SBR. For example, BR may be brought into contact with the modifier. After synthesizing, a predetermined amount of a modifier is added to the polymer rubber solution to react the polymerization terminal (active end) of BR with the modifier, a method of adding a modifier to the BR solution and reacting, etc. Is mentioned.

  Among these various BRs, it is preferable to use an unmodified high cis BR having a cis 1,4 bond content of 90% by mass or more because it has good wear resistance and low fuel consumption.

  The content in 100% by mass of the rubber component in the case of containing BR is preferably 5% by mass or more, and more preferably 8% by mass or more, because it is excellent in wear resistance and steering stability. Further, the BR content is preferably 15% by mass or less, and more preferably 10% by mass or less, from the viewpoint of low fuel consumption.

  Since the hydroxide of the group 13 element excluding the aluminum hydroxide reacts with the coupling agent in the same manner as silica and carbon black, it can be bonded by the polymer-coupling agent-hydroxide of the group 13 element. It exhibits the same reinforcement as silica and carbon black. Group 13 element hydroxides have fewer reactive sites than silica and carbon black, and are easy to move. Therefore, rubber compositions containing Group 13 element hydroxides are supple and well-stretched, resulting in grip performance and handling stability. Excellent. Moreover, since it is not the method of improving grip performance by the increase in the conventional energy loss, the problem that a fuel-consumption property deteriorates does not arise. Furthermore, as mentioned above, Group 13 element hydroxides have the same reinforcing properties as silica and carbon black, so conventional inorganic fillers such as calcium carbonate and magnesium oxide are added to improve grip performance. There is no problem of insufficient wear resistance due to the method used. Therefore, it can be set as the rubber composition which improves grip performance, without deteriorating abrasion resistance and low fuel consumption.

  Examples of the hydroxide of the group 13 element include aluminum hydroxide, gallium hydroxide, indium hydroxide, thallium hydroxide, etc., but the rubber composition according to the first invention is a group 13 excluding aluminum hydroxide. Contains elemental hydroxides. Among group 13 element hydroxides excluding aluminum hydroxide, indium hydroxide is preferred because the particle size is large and the rubber composition is easily stretched.

The nitrogen adsorption specific surface area (N ₂ SA) of the Group 13 element hydroxide excluding aluminum hydroxide is preferably 5 m ² / g or more, more preferably 10 m ² / g or more, from the viewpoint of wear resistance. Also, N ₂ SA of hydroxides of Group 13 elements except aluminum hydroxide, from the viewpoint of dispersibility, preferably less than 30 m ² / g, more preferably 25 m ² / g or less, is 20 m ² / g or less Further preferred. Incidentally, N ₂ SA of the hydroxide of a Group 13 element in the present specification is a value measured by the BET method in accordance with ASTM D3037-81.

  From the viewpoint of dispersibility, the average particle diameter (d50) of the Group 13 element hydroxide excluding aluminum hydroxide is preferably 0.1 μm or more, and more preferably 0.2 μm or more. In addition, the average particle size of the Group 13 element hydroxide excluding aluminum hydroxide is preferably 10 μm or less, more preferably 8 μm or less, from the viewpoint of wear resistance. In addition, the average particle diameter (d50) of the hydroxide of the Group 13 element in this specification is a value calculated from the size distribution (range and content rate) of the powder particles.

  By containing the coupling agent, a bond of the polymer-coupling agent-group 13 element hydroxide can be formed. Therefore, according to the first invention of the present invention, wear resistance and low fuel consumption are deteriorated by using three of group 13 element hydroxide excluding aluminum hydroxide, silica and silane coupling agent in combination. The grip performance can be improved without any problems. Examples of the coupling agent include a silane coupling agent that binds to silica and a polymer, a carbon coupling agent that binds to carbon black and a polymer, and the like.

  The silane coupling agent can be combined with silica and a polymer to improve the dispersibility of the silica, thereby improving the fuel economy and wear resistance of the rubber composition. Further, as described above, a polymer-coupling agent-group 13 element hydroxide bonds are formed, and the rubber composition can be made flexible and stretchable, and has excellent grip performance.

  As the silane coupling agent, conventionally known silane coupling agents can be used as long as they can be combined with a polymer and a hydroxide of a Group 13 element. For example, bis (3-triethoxysilylpropyl) tetrasulfide, Bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis ( 3-trimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3 -Trimet Sulfide systems such as silylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide; 3-mercaptopropyltri Mercapto type such as methoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane; Vinyl type such as vinyltriethoxysilane, vinyltrimethoxysilane; 3-aminopropyltri Ethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) amino Amino series such as propyltrimethoxysilane; γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane Such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2 -Chloro silane coupling agents such as chloroethyltriethoxysilane. In addition, the said silane coupling agent may be used independently and may be used in combination of 2 or more type. Among these, a sulfide-based silane coupling agent is preferable from the viewpoint of availability, and bis (3-triethoxysilylpropyl) tetrasulfide is more preferable.

  Content with respect to 100 mass parts of silicas of a silane coupling agent is 1 mass part or more, 4 mass parts or more are preferable and 9 mass parts or more are more preferable. When content of a silane coupling agent is less than 1 mass part, there exists a tendency for sufficient reinforcement effect and grip performance by containing a silane coupling agent not to be acquired. Moreover, content of a silane coupling agent is 20 mass parts or less, and 15 mass parts or less are preferable. When the content of the silane coupling agent exceeds 20 parts by mass, the rubber composition tends to be cured.

  The carbon coupling agent can be combined with carbon black and a polymer to improve the dispersibility of the carbon black, thereby improving the fuel economy and wear resistance of the rubber composition. Further, as described above, a polymer-coupling agent-group 13 element hydroxide bonds are formed, and the rubber composition can be made flexible and stretchable, and has excellent grip performance.

（化学式（２）中、ｎは１または２、ＭはＺｎ、Ｃｕ、Ｎａ、Ｃａのいずれかである。） Examples of the carbon coupling agent include tetrasulfide compounds such as bis (dimethylaminoethyl) tetrasulfide (DME) and bis (dimethylaminopropyl) tetrasulfide (DMP); 1,2-bis (benzimidazolyl-2) ethane (EBZ). ), 1,4′-bis (mercaptobenzimidazolyl-2) butane (C4SBZ) and other benzimidazole compounds; pyrithione metal salts and the like. Especially, the pyrithione metal salt is preferable from the ease of acquisition, and the pyrithione metal salt represented by following Chemical formula (2) is more preferable.

(In the chemical formula (2), n is 1 or 2, and M is any one of Zn, Cu, Na, and Ca.)

The pyrithione metal salt represented by the chemical formula (2) is pyrithione zinc, pyrithione copper, pyrithione sodium, and pyrithione calcium. Among them, pyrithione zinc is preferable because of its availability. Pyrithione zinc is prepared by reacting 1-hydroxy-2-pyridinethione or a soluble salt thereof with a zinc salt (eg, ZnSO ₄ ) as described, for example, in US Pat. No. 2,809,971. It is manufactured by producing. Commercially available products of pyrithione zinc include bis [1-hydroxy-2 (1H) -pyridinethionate-O, S] zinc (ZPNO) manufactured by FLEXSYS.

  Content with respect to 100 mass parts of carbon black of a carbon coupling agent is 2 mass parts or more, 3 mass parts or more are preferable and 4 mass parts or more are more preferable. When the content of the carbon coupling agent is less than 2 parts by mass, the reinforcing effect is insufficient and the wear resistance tends to be reduced. Moreover, content of a carbon coupling agent is 20 mass parts or less, 18 mass parts or less are preferable and 15 mass parts or less are more preferable. When the content of the carbon coupling agent exceeds 20 parts by mass, the rubber composition tends to be cured.

  In addition to the above components, the rubber composition according to the first aspect of the present invention includes compounding agents conventionally used in the rubber industry, for example, reinforcing agents such as carbon black and silica; fillers such as inorganic fillers; stearic acid Vulcanization activators such as zinc oxide; organic peroxides such as dicumyl peroxide and ditertiary butyl peroxide; processing aids; anti-aging agents; waxes; vulcanizing agents such as sulfur; Vulcanization accelerators such as vulcanizing agents, thiuram vulcanization accelerators, sulfenamide vulcanization accelerators, and guanidine vulcanization accelerators can be appropriately blended.

  The rubber composition according to the first invention preferably contains carbon black because a coloring effect can be obtained.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 100 m ² / g or more, and more preferably 120 m ² / g or more. If it is less than 100 m ² / g, a sufficient reinforcing effect may not be obtained. Also, N ₂ SA of carbon black is preferably 250 meters ² / g or less, more preferably 300m ² / g. If it exceeds 250 m ² / g, the initial grip may be deteriorated. In addition, the nitrogen adsorption specific surface area of carbon black is calculated | required by A method of JISK6217.

  When carbon black is contained, the content is preferably 30 parts by mass or more, and more preferably 35 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 30 parts by mass, the grip-up effect due to sufficient elongation may not be obtained. Moreover, 100 mass parts or less are preferable and, as for content of carbon black, 90 mass parts or less are more preferable. When it exceeds 100 mass parts, there exists a tendency for rolling resistance to deteriorate.

  The rubber composition according to the first invention preferably contains silica for the reason that good fuel efficiency is obtained and a reinforcing effect is obtained.

The nitrogen adsorption specific surface area by silica BET method is preferably 50 m ² / g or more, and more preferably 100 m ² / g or more. If it is less than 50 m ² / g, the rubber strength tends to decrease. Further, the nitrogen adsorption specific surface area by the BET method of the silica is preferably 250 meters ² / g or less, more preferably 200m ² / g. If it exceeds 250 m ² / g, the processability tends to deteriorate. In addition, the nitrogen adsorption specific surface area by BET method of a silica can be measured by the method based on ASTM D3037-81.

  The content of silica is preferably 0 part by mass or more and more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. Moreover, 100 mass parts or less are preferable, as for content of a silica, 90 mass parts or less are more preferable, and 80 mass parts or less are more preferable. By making it within the above range, both grip and rolling resistance can be achieved.

  As the anti-aging agent, amine-based, phenol-based and imidazole-based compounds, carbamic acid metal salts, and the like can be appropriately selected and used. Of these, amine compounds are preferable, and N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine is more preferable.

  When the anti-aging agent is contained, the content with respect to 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, and further preferably 1.2 parts by mass or more. Further, the content of the anti-aging agent is preferably 8 parts by mass or less, more preferably 4 parts by mass or less, and further preferably 2.5 parts by mass or less.

  As the wax, those generally used in the rubber industry such as petroleum waxes such as paraffin wax and microcrystalline wax; non-petroleum waxes such as beeswax and candelilla wax can be used. From the reason that ozone resistance can be improved, it is preferable to use a non-petroleum wax and the anti-aging agent in combination.

  The content with respect to 100 parts by mass of the rubber component in the case of containing the wax is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and further preferably 1.5 parts by mass or more from the viewpoint of deterioration resistance. preferable. Further, the content of the wax is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and further preferably 6 parts by mass or less from the reason that whitening is suppressed.

  It does not specifically limit as a manufacturing method of the rubber composition concerning 1st invention, A well-known method can be used. For example, each of the above components can be produced by a method of kneading using a rubber kneader such as an open roll, a Banbury mixer, a closed kneader, and then vulcanizing.

  The rubber composition according to the first invention is preferably used for a tire tread because the grip performance can be improved without deteriorating the wear resistance and fuel efficiency. Further, when the tread is a tread having a two-layer structure consisting of a cap tread and a base tread, it can be used for both, but it is preferable to use the tread for a cap tread.

  The tire of the first invention can be produced by a normal method using the rubber composition. That is, if necessary, the rubber composition according to the first invention in which the above-mentioned components are blended is extruded in accordance with the shape of the tire tread at an unvulcanized stage, and another tire is formed on the tire molding machine. The unvulcanized tire is formed by bonding together with the members and molding by a normal method. By heating and pressurizing this unvulcanized tire in a vulcanizer, the tire of the first invention can be obtained.

  Since the tire of the first invention can improve grip performance without deteriorating wear resistance and fuel efficiency, it is used as a tire for passenger cars, tires for trucks and buses, tires for motorcycles, competition tires, etc. It is preferable to use it as a tire for passenger cars.

<Second invention>
The tire of the second invention is a rubber composition containing a hydroxide of a group 13 element and a coupling agent with respect to a diene rubber component, and does not contain a hydroxide of a group 13 element. The composition is characterized by comprising a tread composed of a rubber composition having a rubber hardness of −3 to +3 and an elongation at break of 103% or more.

  As the diene rubber component, the rubber component mentioned in the first invention can be used in the same manner as in the first invention, and NR, ENR, SBR and BR are preferable.

  It reacts with the coupling agent in the same manner as the hydroxide silica or carbon black of the group 13 element, and can be bonded by the polymer-coupling agent-hydroxide of the group 13 element. Exhibits reinforcement. Group 13 element hydroxides have fewer reactive sites than silica and carbon black, and are easy to move. Therefore, rubber compositions containing Group 13 element hydroxides are supple and well-stretched, resulting in grip performance and handling stability. Excellent. Moreover, since it is not the method of improving grip performance by the increase in the conventional energy loss, the problem that a fuel-consumption property deteriorates does not arise. Furthermore, as mentioned above, Group 13 element hydroxides have the same reinforcing properties as silica and carbon black, so conventional inorganic fillers such as calcium carbonate and magnesium oxide are added to improve grip performance. There is no problem of insufficient wear resistance due to the method used. Therefore, it can be set as the rubber composition which improves grip performance, without deteriorating abrasion resistance and low fuel consumption.

  Examples of the Group 13 element hydroxide include aluminum hydroxide, gallium hydroxide, indium hydroxide, and thallium hydroxide. Among the hydroxides of group 13 elements, indium hydroxide is preferred because of its large particle size.

The nitrogen adsorption specific surface area (N ₂ SA) of the hydroxide of the group 13 element is preferably 5 m ² / g or more, more preferably 10 m ² / g or more, from the viewpoint of wear resistance. Also, N ₂ SA of hydroxides of Group 13 elements, from the viewpoint of dispersibility, preferably less than 30 m ² / g, more preferably not more than ^{25m 2 / g, 20m 2 /} g or less is more preferred. Incidentally, N ₂ SA of the hydroxide of a Group 13 element in the present specification is a value measured by the BET method in accordance with ASTM D3037-81.

  From the viewpoint of dispersibility, the average particle size (d50) of the Group 13 element hydroxide is preferably 0.1 μm or more, and more preferably 0.2 μm or more. Moreover, the average particle diameter of the hydroxide of the group 13 element is preferably 10 μm or less, more preferably 8 μm or less, from the viewpoint of wear resistance. In addition, the average particle diameter (d50) of the hydroxide of the Group 13 element in this specification is a value calculated from the size distribution (range and content rate) of the powder particles.

  As said coupling agent, the silane coupling agent, carbon coupling agent, etc. which were mentioned by 1st invention can be used similarly to 1st invention.

  In addition to the above components, the rubber composition according to the second invention includes compounding agents conventionally used in the rubber industry, for example, reinforcing agents such as carbon black and silica; fillers such as inorganic fillers; stearic acid, zinc oxide Vulcanization activators such as dicumyl peroxide, organic peroxide such as ditertiary butyl peroxide, processing aids, anti-aging agents, waxes, sulfur vulcanizing agents, thiazole vulcanization accelerators, thiuram A vulcanization accelerator such as a vulcanization accelerator, a sulfenamide vulcanization accelerator, and a guanidine vulcanization accelerator can be appropriately blended as in the first invention.

  The rubber composition according to the second invention is characterized in that the rubber hardness and elongation at break compared to the reference rubber composition are predetermined values. By using a tire having a tread composed of a rubber composition satisfying the rubber hardness and elongation at break, a tire excellent in grip performance can be obtained without deteriorating wear resistance and fuel efficiency.

  The reference rubber composition is a rubber composition obtained by the same composition and production method as the rubber composition to be compared except that it does not contain a hydroxide of a Group 13 element.

  The hardness of the rubber composition according to the second invention is -3 to +3 of the hardness of the reference rubber composition, and is preferably -2 to +2. When the hardness is less than −3 of the reference rubber composition, the steering stability may be deteriorated. Moreover, when hardness exceeds +3 of a reference | standard rubber composition, there exists a possibility that grip performance may deteriorate. In addition, the rubber hardness in this specification is a hardness measured by a type A durometer in an atmosphere of 25 ° C. according to JIS K6253-3: 2012.

  The elongation at break according to the second invention is 103% or more, and preferably 105% or more of the elongation at break of the reference rubber composition. When the elongation at break is less than 103% of the reference rubber composition, there is a possibility that the effect of improving the grip performance cannot be obtained. Moreover, the upper limit of elongation at break is not particularly limited. In addition, the elongation at break in this specification is the elongation at break measured at room temperature using a No. 3 dumbbell type test piece according to JIS K6251: 2010.

  It does not specifically limit as a manufacturing method of the rubber composition concerning 2nd invention, A well-known method can be used. For example, each of the above components can be produced by a method of kneading using a rubber kneader such as an open roll, a Banbury mixer, a closed kneader, and then vulcanizing.

  The rubber composition according to the second invention is preferably used for a tire tread because the grip performance can be improved without deteriorating the wear resistance and fuel efficiency. Further, when the tread is a tread having a two-layer structure consisting of a cap tread and a base tread, it can be used for both, but it is preferable to use the tread for a cap tread.

  The tire of the second invention can be produced by a normal method using the rubber composition. That is, if necessary, the rubber composition according to the second invention in which the above-mentioned components are blended is extruded according to the shape of the tread of the tire at an unvulcanized stage, and the other tires on the tire molding machine. The unvulcanized tire is formed by bonding together with the members and molding by a normal method. By heating and pressurizing this unvulcanized tire in a vulcanizer, the tire of the first invention can be obtained.

  Since the tire of the second invention can improve grip performance without deteriorating wear resistance and fuel efficiency, it is used as a tire for passenger cars, tires for trucks and buses, tires for motorcycles, competition tires, etc. It is preferable to use it as a tire for passenger cars.

  The present invention will be described based on examples, but the present invention is not limited to the examples.

Hereinafter, various chemicals used in Examples and Comparative Examples are shown together.
S-SBR: Toughden 4350 manufactured by Asahi Kasei Corporation (bonded styrene content: 40% by mass, vinyl bond content: 38 mol%, containing 50 parts by weight of oil with respect to 100 parts by weight of rubber solid content)
Modified SBR: HPR350 (modified S-SBR, manufactured by JSR Co., Ltd., bound styrene content: 21 mass%, vinyl bond content: 56 mol%, coupled with alkoxysilane, introduced at the end, represented by chemical formula (1) Modified by a compound (in the chemical formula (1), R ^{1 to} R ³ = methoxy group, R ⁴ and R ⁵ = hydrogen atom, m = 3)
NR: RSS # 3
BR: UBEPOL BR150B manufactured by Ube Industries, Ltd. (High cis BR, cis 1,4 bond content: 97% by mass)
Silica: Ultrazil VN3 manufactured by Degussa (N ₂ SA: 175 m ² / g)
Carbon black: Dia Black A (N110, N ₂ SA: 142 m ² / g, DBP: 116 ml / 100 g) manufactured by Mitsubishi Chemical Corporation
Aluminum hydroxide: ATH # B manufactured by Sumitomo Chemical Co., Ltd. (average particle size: 0.6 μm, N ₂ SA: 15 m ² / g)
Indium hydroxide: Showa Chemical Co., Ltd. (average particle size: 0.8 μm, N ₂ SA: 20 m ² / g)
Inorganic filler 1: White sinter flower CC (calcium carbonate, average particle size: 1 μm) manufactured by Shiroishi Kogyo Co., Ltd.
Inorganic filler 2: PUREMAG FNM-G (magnesium oxide, average particle size: 2 μm) manufactured by Tateho Chemical Co., Ltd.
Oil: Diana Process Oil X140 from Japan Energy Co., Ltd.
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa
Carbon coupling agent: Zinc pyrithione manufactured by FLEXSYS (compound represented by chemical formula (2) (bis [1-hydroxy-2 (1H) -pyridinethionate-O, S] zinc (ZPNO), in chemical formula (2) , N = 2, M = Zn)
Anti-aging agent: NOCRACK 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Wax: Sunnock N (petroleum wax) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Stearic acid: Stearic acid “paulownia” manufactured by NOF Corporation
Zinc oxide: Zinc oxide type 2 vulcanization accelerator manufactured by Mitsui Mining & Smelting Co., Ltd. 1: Noxeller D (DPG, 1,3-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Vulcanization accelerator 2: Noxeller CZ (CZ, N-cyclohexyl-2-benzothiazolesulfenamide) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd.

Examples and Comparative Examples In accordance with the blending contents shown in Tables 1 and 2, materials other than sulfur and a vulcanization accelerator were discharged under a condition of an exhaust temperature of 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel Co., Ltd. The mixture was kneaded for 5.0 minutes to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product and kneaded for 3.0 minutes under the condition of a discharge temperature of 100 ° C. to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was press vulcanized with a 2 mm thick mold at 170 ° C. for 12 minutes to obtain a sheet-like vulcanized rubber composition. Further, the obtained unvulcanized rubber composition was molded into a tread shape, and bonded together with other tire members on a tire molding machine to form an unvulcanized tire, and press vulcanized at 170 ° C. for 12 minutes, A test tire (size: 195 / 65R15) was produced. The following evaluation was performed about the obtained vulcanized rubber composition and the tire for a test. Comparative Example 1 is a reference example of Examples 1 to 3 and Comparative Examples 2 and 3, Comparative Example 4 is a reference example of Examples 4 and 5 and Comparative Example 5, and Comparative Example 6 is of Example 6 and Comparative Example 7. Reference Example, Comparative Example 8 is the Reference Example of Examples 7 and 8, and Comparative Examples 9 and 10, Comparative Example 11 is the Reference Example of Example 9 and Comparative Examples 12 and 13, and Comparative Example 14 is Example 10 and Comparative Example 15. And 16 reference examples.

<Rubber hardness>
According to JIS K6253-3: 2012, the type A durometer hardness (rubber hardness) of the tire tread portion was measured under an atmosphere of 25 ° C.

<Elongation at break EB>
In accordance with JIS K6251: 2010, a tensile test was performed at room temperature using a No. 3 dumbbell-shaped test piece made of each vulcanized rubber composition, and the elongation at break EB (%) of each vulcanized rubber composition was measured. Then, the EB of each formulation was displayed as an index according to the following formula.
(EB index) = (EB of each formulation) / (EB of each reference example) × 100

<Grip performance>
Each test tire with an internal pressure of 180 kPa was mounted on all wheels of T & T Corporation's traction bus, and the peak μ was measured immediately before the control system equipped on the test tire shaft locked the wheel at 65 km / h. . The grip performance of each formulation was displayed as an index according to the following formula. The larger the index, the larger the peak μ and the higher the grip performance.
(Grip performance index) = (Peak μ of each formulation) / (Peak μ of each reference example) × 100

<Rolling resistance>
The loss tangent (tan δ) of each vulcanized rubber composition was measured under the conditions of a temperature of 70 ° C., an initial strain of 10% and a dynamic strain of 2% using a viscoelastic spectrometer VES manufactured by Iwamoto Seisakusho. The rolling resistance characteristics of each formulation were indicated by an index according to the following formula. The larger the index, the better the rolling resistance characteristics (low fuel consumption).
(Rolling resistance index) = (tan δ of each reference example) / (tan δ of each formulation) × 100

<Abrasion resistance>
The amount of wear of each vulcanized rubber composition was measured under the conditions of room temperature, applied load of 1.0 kg, and slip rate of 30% using a Lambone-type wear tester manufactured by Iwamoto Seisakusho. The wear resistance of each formulation was displayed as an index according to the following formula. The larger the index, the smaller the amount of wear and the better the wear resistance.
(Abrasion resistance index) = (Abrasion amount of each reference example) / (Abrasion amount of each formulation) × 100

  From the results of Tables 1 and 2, it can be seen that the tire of the first invention and the tire of the second invention are excellent in grip performance without deteriorating wear resistance and fuel efficiency.

Claims (2)

A tire comprising a tread composed of a rubber composition containing a hydroxide of a group 13 element excluding aluminum hydroxide and a coupling agent. A rubber composition containing a hydroxide of a Group 13 element and a coupling agent;
A tire provided with a tread composed of a rubber composition having a rubber hardness of -3 to +3 and an elongation at break of 103% or more with respect to a reference rubber composition not containing a hydroxide of a Group 13 element .