JP6848490B2 - Rubber composition for tires and pneumatic tires - Google Patents

Description

The present invention relates to a rubber composition for a tire and a pneumatic tire using the same.

In recent years, with the demand for safety and fuel efficiency of automobiles, it has been desired to simultaneously improve wet grip performance, fuel efficiency and wear resistance of rubber materials for tires, but these are in a trade-off relationship with each other. It is generally difficult to improve in a well-balanced manner.

As a method for solving such a problem, a method using silica (low heat generation filler) is known, but silica tends to agglomerate particles due to hydrogen bonds of silanol groups which are surface functional groups thereof. There is a problem that the workability is inferior because the dispersion is insufficient.

Therefore, a silane coupling agent has been developed as a material for improving silica dispersibility. For example, Patent Document 1 proposes bis (3-triethoxysilylpropyl) tetrasulfide and the like. However, further improvements are desired in obtaining a performance balance of high level of workability, wet grip performance, fuel efficiency and wear resistance.

Patent No. 4266248

The present invention provides a rubber composition for a tire capable of remarkably improving the performance balance of workability, wet grip performance, fuel efficiency and wear resistance, and a pneumatic tire using the same. With the goal.

The first invention is a rubber for a tire containing a modified polymer and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more carbon atoms connecting the alkoxysilyl group and the sulfur atom. Regarding the composition.

The second invention is a rubber composition for a tire containing a resin and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more carbon atoms connecting the alkoxysilyl group and the sulfur atom. Regarding things.

A third invention is a rubber for a tire containing a liquid polymer and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more carbon atoms connecting the alkoxysilyl group and the sulfur atom. Regarding the composition.

The fourth invention comprises a processing aid composed of a fatty acid metal salt and / or a fatty acid amide, an alkoxysilyl group and a sulfur atom, and the number of carbon atoms connecting the alkoxysilyl group and the sulfur atom is 6 or more. The present invention relates to a rubber composition for a tire containing a silane coupling agent.

The fifth invention comprises fine particle silica having a nitrogen adsorption specific surface area of 160 m ² / g or more, an alkoxysilyl group and a sulfur atom, and the number of carbon atoms connecting the alkoxysilyl group and the sulfur atom is 6 or more. The present invention relates to a rubber composition for a tire containing a silane coupling agent.

The present invention also relates to a pneumatic tire produced using the above rubber composition.

According to the first to fifth inventions, since it is a rubber composition for a tire containing a silane coupling agent specific to the present application and at least one of a modified polymer, a resin, a liquid polymer, a processing aid and fine silica, the rubber composition is processed. The performance balance of property, wet grip performance, fuel efficiency and wear resistance can be remarkably improved.

The rubber composition for a tire of the first invention comprises a modified polymer and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more carbon atoms connecting the alkoxysilyl group and the sulfur atom. Contains.
By using the modified polymer in combination with the silane coupling agent specified in the present application, the performance balance of workability, wet grip performance, fuel efficiency and wear resistance can be remarkably (synergistically) improved.

The reason why the rubber composition for tires of the first invention has the above effect is presumed as follows.
The purpose of using the modified polymer is to improve μRR by improving silica dispersion, but it has been clarified as a result of the studies by the present inventors that the modified polymer is difficult to increase in molecular weight and strength and is inferior in wear resistance. In the formulation with the modified polymer having such characteristics as the main axis, it is possible to aim at improving the wear resistance with materials other than the polymer, but it became clear that it is difficult to balance with the workability. .. Since the silane coupling agent specified in the present application can improve the balance between wear resistance and workability, the workability and wet grip performance can be improved by using the silane coupling agent specified in the present application together with the modified polymer. Fuel efficiency and wear resistance can be improved in a highly balanced manner.

The rubber composition for a tire of the second invention comprises a resin and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more carbon atoms connecting the alkoxysilyl group and the sulfur atom. contains.
By using the resin in combination with the silane coupling agent specified in the present application, the performance balance of workability, wet grip performance, fuel efficiency and wear resistance can be remarkably (synergistically) improved.

The reason why the rubber composition of the second invention has the above effect is presumed as follows.
Resin is added mainly for the purpose of improving wet grip performance in cap tread formulation, but most of them have a softening point of 80 to 100 ° C and act as a plasticizer during mixing, so if you want to design with high hardness, or As a result of the examination by the present inventors, it has been clarified that there is a problem that the hardness cannot be balanced when the resin is added in the case of a formulation in which the amount of free oil added is small. Since there is a merit of increasing hardness by using the silane coupling agent specified in the present application, by using the silane coupling agent specified in the present application together with the resin, the above problems do not occur, and the workability and wet grip performance are improved. The performance balance between fuel efficiency and wear resistance can be significantly improved.

The rubber composition for a tire of the third invention comprises a liquid polymer and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more carbon atoms connecting the alkoxysilyl group and the sulfur atom. Contains.
By using the liquid polymer in combination with the silane coupling agent specified in the present application, the performance balance of workability, wet grip performance, fuel efficiency and wear resistance can be remarkably (synergistically) improved.

The reason why the rubber composition of the third invention has the above effect is presumed as follows.
Liquid polymer is added mainly for the purpose of improving wet grip performance in cap tread formulation, but when designing with high hardness or when compounding with a small amount of free oil added, adding liquid polymer balances hardness. As a result of the examination by the present inventors, it became clear that there is a problem that the oil cannot be removed. Since there is a merit of increasing hardness by using the silane coupling agent specified in the present application, by using the silane coupling agent specified in the present application in combination with the liquid polymer, the above problems do not occur and the workability and wet grip performance are improved. , The performance balance of fuel efficiency and abrasion resistance can be remarkably (synergistically) improved.

The rubber composition for a tire of the fourth invention contains a processing aid composed of a fatty acid metal salt and / or a fatty acid amide, an alkoxysilyl group and a sulfur atom, and the number of carbon atoms connecting the alkoxysilyl group and the sulfur atom. Contains 6 or more silane coupling agents.
By using the above processing aid and the silane coupling agent specified in the present application in combination, the performance balance of workability, wet grip performance, fuel efficiency and wear resistance can be remarkably (synergistically) improved.

The reason why the rubber composition of the fourth invention has the above effect is presumed as follows.
The processing aid is added for the purpose of improving processability, but its action in rubber is to prevent excessive reaction of silica. Originally, the expected effect can be obtained by sufficiently reacting silica with a polymer or a silane coupling agent, so that adding a processing aid may lead to a problem of reducing the potential of other materials. It became clear as a result of the examination by the present inventors. By using the silane coupling agent specified in the present application, the processability is improved and the compounding design can be performed without inhibiting the reaction with silica. As a result, the processing aid is suppressed. It is possible to fully bring out the compounding potential that had been used. Therefore, by using the silane coupling agent specified in the present application together with the processing aid, the performance balance of workability, wet grip performance, fuel efficiency and wear resistance can be remarkably (synergistically) improved.

The rubber composition for a tire of the fifth invention contains ^{fine particle silica having a nitrogen adsorption specific surface area of 160 m 2} / g or more, an alkoxysilyl group and a sulfur atom, and the number of carbon atoms connecting the alkoxysilyl group and the sulfur atom. Contains 6 or more silane coupling agents.
By using the above-mentioned fine particle silica in combination with a specific silane coupling agent, the performance balance of workability, wet grip performance, fuel efficiency and wear resistance can be remarkably (synergistically) improved.

The reason why the rubber composition of the fifth invention has the above effect is presumed as follows.
Fine particle silica is significantly excellent in improving wet grip performance and wear resistance, but the workability is significantly sacrificed. In particular, fine-grained silica has a strong cohesive force between silicas, and it is necessary to apply high shear to sufficiently break it, and in order to apply high shear, it is generally considered to knead at a high rotation speed. However, the heat generation speed of the rubber increases, and the reaction temperature of the silica coupling agent is reached at the initial stage of mixing. As a result of the studies by the present inventors, it has been clarified that if the kneading time at the initial stage of mixing cannot be sufficiently secured, the silica reacts with the silane coupling agent as agglomerates and the characteristics as fine particle silica cannot be obtained. became. Since the silane coupling agent specified in the present application can be kneaded even at a high temperature, it is possible to set a high rotation speed to impart initial shear, and as a result, silica agglomerates can be broken, resulting in efficient silanization thereafter. Connect. Further, the workability improving effect of the silane coupling agent specified in the present application can offset the poor workability of the fine particle silica, and an improving effect can be found in terms of both performance and workability. Therefore, by using the silane coupling agent specified in the present application together with the fine particle silica, the performance balance of workability, wet grip performance, fuel efficiency and wear resistance can be remarkably (synergistically) improved.

First, a specific silane coupling agent common to the first to fifth inventions will be described.

[Silane coupling agent]
The rubber composition of the present invention contains a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more carbon atoms connecting the alkoxysilyl group and the sulfur atom.

（式中、ｘは、硫黄原子の平均個数を表す。ｍは、６〜１２の整数を表す。Ｒ^１〜Ｒ^６は、同一若しくは異なって炭素数１〜６のアルキル基又はアルコキシ基を表し、Ｒ^１〜Ｒ^３の少なくとも１つ及びＲ^４〜Ｒ^６の少なくとも１つが前記アルコキシ基である。なお、Ｒ^１〜Ｒ^６は、前記アルキル基又は前記アルコキシ基が結合した環構造を形成したものでもよい。） Examples of the silane coupling agent include organic silicon compounds represented by the following average composition formula (I) and having a number of sulfur atoms / number of silicon atoms of 1.0 to 1.5.

(In the formula, x represents the average number of sulfur atoms. M represents an integer of 6 to 12. R ^{1 to} R ⁶ represent the same or different alkyl or alkoxy groups having 1 to 6 carbon atoms. , At ^{least one of R 1 to} R ³ and at least one of R ^{4 to} R ⁶ are the alkoxy groups. In addition, R ^{1 to} R ⁶ formed a ring structure in which the alkyl group or the alkoxy group was bonded. It may be one.)

By using the organic silicon compound of the formula (I) as a silane coupling agent in a rubber compound containing an inorganic filler, workability, which is generally a problem in silica compounding, wet grip performance and abrasion resistance, which are contradictory to each other, are achieved. , Found to improve fuel efficiency in a well-balanced manner.

The reason why such an action effect was obtained is not always clear, but it is presumed as follows.

Silane and rubber are crosslinked by an organic silicon compound (silane coupling agent). As a silane coupling agent, the number of carbon atoms between sulfur atoms and silicon atoms is 6 to 12, according to the above formula (I). By using the compound of, the length of the bond between silica and rubber becomes longer than that of a general silane coupling agent. Therefore, it is presumed that a certain degree of flexibility is imparted to the crosslinked portion and the wet grip performance is improved. In addition, it is easy to relieve the external stress that leads to the breakage of rubber, and it is presumed that the wear resistance is improved as compared with a general silane coupling agent. Furthermore, when the number of carbon atoms between silicon and sulfur is longer than that of a general silane coupling agent, the rate of silanization is slightly slowed down, so that excessive bonding between silica and rubber during kneading is suppressed. It is presumed that good workability can also be obtained. Therefore, workability, wet grip performance, wear resistance and fuel efficiency can be improved in a well-balanced manner.

x represents the average value of the sulfur number of the organic silicon compound. That is, the organic silicon compound represented by the average composition formula (I) is a mixture of compounds having different sulfur numbers, and the average value of the sulfur numbers of the organic silicon compounds contained in the rubber composition is x. x is represented by {2 × (number of sulfur atoms)} / (number of silicon atoms). From the viewpoint of fuel efficiency and wear resistance, x is preferably 2.0 to 2.4, more preferably 2.0 to 2.3. In particular, when x is less than the upper limit, an increase in the Mooney viscosity of the unvulcanized rubber is suppressed, and good processability can be obtained. Here, the number of sulfur atoms and the number of silicon atoms are values obtained by measuring the amount of sulfur and the amount of silicon in the composition by fluorescent X-rays and converting them from their respective molecular weights.

m represents an integer of 6 to 12, preferably 6 to 10, and more preferably 8. As a result, the above-mentioned effects are exhibited, and the effects of the present invention can be sufficiently obtained.

The alkyl group (R ^{1 to} R ⁶ ) preferably has 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms from the viewpoint of the performance balance. The alkyl group may be linear, branched or cyclic. Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group and the like.

The alkoxy group (R ^{1 to} R ⁶ ) preferably has 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms from the viewpoint of the performance balance. The hydrocarbon group in the alkoxy group may be linear, branched or cyclic. Specific examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group and the like.

At least one of the at least one and ^R 4 to R ⁶ in R ¹ to R ³ is an alkoxy group having 1 to 6 carbon atoms, ^preferably, each of the two or more of ^{R 1 ~R 3, R 4 ~R} 6 It is an alkoxy group.

In addition, R ^{1 to} R ⁶ may form a ring structure in which an alkyl group having 1 to 6 carbon atoms and an alkoxy group are bonded. For example, when (i) R ¹ forms a ring structure in which an ethoxy group and R ² are bonded to a methyl group, and (ii) R ¹ forms a ring structure in which an ethyl group and R ² are bonded to a methyl group, respectively. A structure in which divalent groups "-OC ₂ H _4- CH _2- " and "-C ₂ H _4- CH _2- ^{" are formed in 1} and R ² and bonded to Si can be mentioned.

The organic silicon compound has a number of sulfur atoms / a number of silicon atoms of 1.0 to 1.5. That is, in the organic silicon compound represented by the average composition formula (I) contained in the rubber composition, the ratio of the total number of sulfur to the total number of silicon is in the above range.

The number of sulfur atoms / the number of silicon atoms is preferably 1.0 to 1.2, more preferably 1.0 to 1.15, from the viewpoint of fuel efficiency and wear resistance.

（式中、Ｒ^１〜Ｒ^３及びｍは、上記と同様である。Ｘは、ハロゲン原子を表す。）
で表されるハロゲン基含有有機珪素化合物、及びＮａ_２Ｓで表される無水硫化ソーダ、更に必要により硫黄を反応させることにより、前記有機珪素化合物を製造できる。 The organic silicon compound represented by the average composition formula (I) and having the number of sulfur atoms / the number of silicon atoms in a predetermined range can be prepared, for example, by the following production method.
The following formula (I-1)

(In the formula, R ^{1 to} R ³ and m are the same as above. X represents a halogen atom.)
The organic silicon compound can be produced by reacting the halogen group-containing organic silicon compound _{represented by (2} ), anhydrous sodium sulfide represented by Na 2S, and if necessary, sulfur.

Examples of X (halogen atom) include Cl, Br, I and the like.

Examples of the compound constituting the sulfide chain-containing organic silicon compound represented by the average composition formula (I) include the following.

Examples of the halogen group-containing organic silicon compound of the above formula (I-1) include the following.

When the above reaction is carried out, the addition of sulfur is optional for the adjustment of the sulfide chain, and the compound of the formula (I-1) and the anhydrous soda sulfide are used so as to obtain a compound having a desired average composition formula (I). It may be determined from the blending amount.

For example, when it is desired to set x of the compound of the average composition formula (I) to 2.2, 1.0 mol of anhydrous sodium sulfide, 1.2 mol of sulfur, and 2.0 mol of the compound of the formula (I-1) can be reacted. Just do it.

The use of the solvent at that time is optional and may be solvent-free, but aliphatic hydrocarbons such as pentane and hexane, aromatic hydrocarbons such as benzene, toluene and xylene, tetrahydrofuran, diethyl ether, dibutyl ether and the like. Solvents such as ethers and alcohols such as methanol and ethanol may be used, and it is particularly preferable to use ether such as tetrahydrofuran and alcohols such as methanol and ethanol for the reaction.

The reaction temperature at that time is not particularly limited, but may be about room temperature to 200 ° C., particularly preferably 60 to 170 ° C., and even more preferably 60 to 100 ° C. The reaction time is 30 minutes or more, but the reaction is completed in about 2 to 15 hours.

In the present invention, when a solvent is used, the salt produced after the reaction is completed may be distilled off under reduced pressure before or after filtering.

As the silane coupling agent, for example, products such as Degussa, Momentive, Shinetsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., Toray Dow Corning Co., Ltd. can be used.

In the rubber composition of the present invention, the content of the silane coupling agent is preferably 0.5 parts by mass or more, more preferably 3 parts by mass or more, and 6 parts by mass or more with respect to 100 parts by mass of the silica content. Is more preferable. When the amount is 0.5 parts by mass or more, a sufficient chemical bond between rubber and silica is formed via a silane coupling agent, and good silica dispersibility can be obtained, so that fuel efficiency and abrasion resistance can be obtained. , Wet grip performance is improved. The silane coupling agent is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less. By setting the content to 25 parts by mass or less, good workability can be ensured.

Next, each combination agent in the first to fifth inventions will be described.

[First invention: modified polymer]
The rubber composition of the first invention contains a modified polymer as a rubber component.

The modified polymer may be a modified polymer having a functional group that interacts with an inorganic filler such as silica (particularly, a modified rubber). For example, at least one end of the rubber may be a compound having the above functional group (modifying agent). ) Modified terminal modified rubber (terminal modified rubber having the above functional group at the end), main chain modified rubber having the above functional group in the main chain, and main chain terminal modification having the above functional group in the main chain and the end. Modified with a rubber (for example, a main chain terminal modified rubber having the above functional group in the main chain and at least one end modified with the above modifying agent) or a polyfunctional compound having two or more epoxy groups in the molecule. Examples thereof include end-modified rubber that has been (coupled) and has a hydroxyl group or an epoxy group introduced therein.

Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group and a disulfide. Examples thereof include a group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group and an epoxy group. .. In addition, these functional groups may have a substituent. Among them, an amino group (preferably an amino group in which the hydrogen atom of the amino group is replaced with an alkyl group having 1 to 6 carbon atoms) and an alkoxy group (preferably) because the effect of the present invention can be obtained more preferably. An alkoxy group having 1 to 6 carbon atoms) and an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms) are preferable.

The rubbers constituting the skeleton of the modified rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), and ethylene propylene diene rubber (EPDM). ), Chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR) and the like. These may be used alone or in combination of two or more. Of these, BR and SBR (that is, modified BR and modified SBR) are preferable.

As the modified rubber, a rubber modified with a compound (modifying agent) represented by the following formula (1) (S-modified rubber) is preferable.

（式（１）中、Ｒ^１１、Ｒ^１２及びＲ^１３は、同一又は異なって、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（−ＣＯＯＨ）、メルカプト基（−ＳＨ）又はこれらの誘導体を表す。Ｒ^１４及びＲ^１５は、同一又は異なって、水素原子又はアルキル基を表す。Ｒ^１４及びＲ^１５は結合して窒素原子と共に環構造を形成してもよい。ｎは整数を表す。）

(In the formula (1), R ¹¹ , R ¹² and R ¹³ are the same or different, alkyl group, alkoxy group, silyloxy group, acetal group, carboxyl group (-COOH), mercapto group (-SH) or these. Derivatives. R ¹⁴ and R ¹⁵ may be the same or different and represent a hydrogen atom or an alkyl group. R ¹⁴ and R ¹⁵ may be combined to form a ring structure with a nitrogen atom. N represents an integer. .)

Among the S-modified rubbers, the styrene-butadiene rubber (S-modified S-) in which the polymerization end (active end) of the solution-polymerized styrene-butadiene rubber (S-SBR) is modified by the compound represented by the above formula (1). SBR (modified SBR described in JP-A-2010-111753)) is preferably used.

^{In the above formula (1), an alkoxy group is preferable as R 11} , R ¹² and R ¹³ (preferably having 1 to 8 carbon atoms) from the viewpoint of obtaining excellent fuel efficiency, fracture characteristics and wear resistance. , More preferably an alkoxy group having 1 to 4 carbon atoms). Alkyl groups (preferably alkyl groups having 1 to 3 carbon atoms) are suitable as R ¹⁴ and R ^15. n is preferably 1 to 5, more preferably 2 to 4, and even more preferably 3. Further, when R ¹⁴ and R ¹⁵ are bonded to form a ring structure together with a nitrogen atom, a 4- to 8-membered ring is preferable. The alkoxy group also includes a cycloalkoxy group (cyclohexyloxy group, etc.) and an aryloxy group (phenoxy group, benzyloxy group, etc.).

Specific examples of the compound represented by the above formula (1) include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, and 3-dimethylaminopropyltriethoxy. Examples thereof include silane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. Of these, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropyltriethoxysilane, and 3-diethylaminopropyltrimethoxysilane are preferable because the above-mentioned performance can be satisfactorily improved. These may be used alone or in combination of two or more.

The amount of styrene in the modified SBR is preferably 5% by mass or more, more preferably 10% by mass or more. When it is 5% by mass or more, good wet grip performance tends to be obtained. The amount of styrene is preferably 50% by mass or less, more preferably 40% by mass or less. When it is 50% by mass or less, heat generation is small, and good fuel efficiency tends to be obtained.
In the present specification, a styrene of the modified SBR ^is calculated by H 1 -NMR measurement.

The amount of vinyl in the modified SBR or the modified BR is preferably 20% by mass or more, more preferably 30% by mass or more. When it is 20% by mass or more, good wet grip performance tends to be obtained. The amount of vinyl is preferably 70% by mass or less, more preferably 60% by mass or less. When it is 70% by mass or less, good wear resistance tends to be obtained.
In the present specification, the amount of vinyl (1,2-bonded butadiene unit amount) of the modified BR can be measured by infrared absorption spectrum analysis.

The weight average molecular weight (Mw) of the modified polymer is preferably 50,000 or more, more preferably 100,000 or more. When it is 50,000 or more, good rubber strength and wear resistance tend to be obtained. The Mw is preferably 3,000,000 or less, more preferably 1500,000 or less. When it is 3,000,000 or less, good processability tends to be obtained at the time of kneading.
In the present specification, Mw of the modified polymer is a value converted from standard polystyrene using a gel permeation chromatograph (GPC).

As the modified polymer, for example, products of Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Co., Ltd., Nippon Zeon Co., Ltd., Dow Co., Ltd. and the like can be used.

In the rubber composition of the first invention, the total content of the modified polymer in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more. The content may be 100% by mass, but is preferably 95% by mass or less, more preferably 90% by mass or less, and further preferably 80% by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained better.

[Second invention: resin]
The rubber composition of the second invention contains a resin.

The resin is not particularly limited as long as it is generally used in the tire industry, and for example, a kumaron inden resin, an α-methylstyrene resin, a terpene resin, and a dicyclopentadiene resin (DCPD resin). ), C5 based petroleum resin, C9 based petroleum resin, C5C9 based petroleum resin, pt-butylphenol acetylene resin, acrylic resin and the like. These may be used alone or in combination of two or more. Of these, kumaron inden-based resins, α-methylstyrene-based resins, terpene-based resins, and DCPD-based resins are preferable from the viewpoint that the effects of the present invention can be obtained more satisfactorily.

The kumaron inden resin is a resin containing kumaron and inden as monomer components constituting the skeleton (main chain) of the resin, and styrene and α-methylstyrene are the monomer components contained in the skeleton other than kumaron and inden. , Methylindene, vinyltoluene and the like.

Examples of the α-methylstyrene resin include an α-methylstyrene homopolymer and a copolymer of α-methylstyrene and styrene.

Examples of the terpene-based resin include polyterpenes, terpene phenols, and aromatic-modified terpene resins.
Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. The terpene compound is _{a hydrocarbon having a composition of (C 5} H ₈ ) _n and an oxygen-containing derivative thereof, and is a mono terpene (C ₁₀ H ₁₆ ), a sesqui terpene (C ₁₅ H ₂₄ ), and a diterpene (C ₂₀ H _32). ) Etc., and are compounds having a terpene as a basic skeleton. , 1,8-Cineol, 1,4-Cineol, α-terpineol, β-terpineol, γ-terpineol and the like.

Examples of the polyterpene include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin made from the above-mentioned terpene compound, and hydrogen added to the terpene resin. Additive terpene resin can also be mentioned.
Examples of the terpene phenol include a resin obtained by copolymerizing the above-mentioned terpene compound and a phenol-based compound, and a resin obtained by hydrogenating the resin. Specifically, the above-mentioned terpene compound, the phenolic compound and the formalin are condensed. Resin is mentioned. Examples of the phenolic compound include phenol, bisphenol A, cresol, xylenol and the like.
Examples of the aromatic-modified terpene resin include a resin obtained by modifying the terpene resin with an aromatic compound, and a resin obtained by hydrogenating the resin. The aromatic compound is not particularly limited as long as it has an aromatic ring, but for example, phenol compounds such as phenol, alkylphenol, alkoxyphenol, and unsaturated hydrocarbon group-containing phenol; naphthol, alkylnaphthol, alkoxynaphthol, and the like. Naftor compounds such as unsaturated hydrocarbon group-containing naphthol; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and unsaturated hydrocarbon group-containing styrene; kumaron, inden and the like can be mentioned.

Examples of the dicyclopentadiene-based resin include petroleum resins produced using dicyclopentadiene, which is a dimer of cyclopentadiene extracted from the C5 distillate of petroleum, as a main raw material.

The softening point of the resin is preferably 30 ° C. or higher, more preferably 60 ° C. or higher, and even more preferably 80 ° C. or higher. At 30 ° C. or higher, the desired wet grip performance tends to be obtained. The softening point is preferably 160 ° C. or lower, more preferably 130 ° C. or lower. When the temperature is 160 ° C. or lower, the dispersibility of the resin is good, and the wet grip performance and fuel efficiency tend to be improved.
In the present invention, the softening point of the resin is the temperature at which the ball drops when the softening point defined in JIS K 6220-1: 2001 is measured by a ring-ball type softening point measuring device.

Examples of resins include Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Toso Co., Ltd., Rutgers Chemicals Co., Ltd., BASF, Arizona Chemical Co., Ltd., Nikko Chemical Co., Ltd., Co., Ltd. Products such as Nippon Shokubai, JX Energy Co., Ltd., Arakawa Chemical Industry Co., Ltd., and Taoka Chemical Industry Co., Ltd. can be used.

In the rubber composition of the second invention, the content of the resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more, based on 100 parts by mass of the rubber component. When it is 1 part by mass or more, good wet grip performance and wear resistance tend to be obtained. The content is preferably 200 parts by mass or less, more preferably 50 parts by mass or less, and further preferably 30 parts by mass or less. When it is 200 parts by mass or less, good fuel efficiency tends to be obtained.

[Third invention: liquid polymer]
The rubber composition of the third invention contains a liquid polymer.

Examples of the liquid polymer include a liquid diene polymer and the like.
The liquid diene polymer is a diene polymer in a liquid state at room temperature (25 ° C.). Liquid diene polymer preferably has a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) (Mw) is a ^{1.0 × 10 3 ~2.0 × 10 5} , 3.0 More preferably, it is × 10 ^{3 to} 1.5 × 10 ^4.

Examples of the liquid diene polymer include a liquid styrene-butadiene copolymer (liquid SBR), a liquid butadiene polymer (liquid BR), a liquid isoprene polymer (liquid IR), and a liquid styrene isoprene copolymer (liquid SIR). Be done. These may be used alone or in combination of two or more. Of these, liquid SBR is preferable because it provides a good balance between wear resistance and wet grip performance.

The amount of styrene in the liquid SBR is preferably 10% by mass or more, more preferably 20% by mass or more. The amount of styrene is preferably 60% by mass or less, more preferably 50% by mass or less. Within the above numerical range, good wet grip performance tends to be obtained.
Incidentally, styrene content of liquid SBR ^is calculated by H 1 -NMR measurement.

As the liquid polymer, for example, products such as Kuraray Co., Ltd. and Clay Valley Co., Ltd. can be used.

In the rubber composition of the third invention, the content of the liquid polymer is preferably 3 parts by mass or more, more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. When it is 3 parts by mass or more, good wet grip performance tends to be obtained. The content is preferably 100 parts by mass or less, more preferably 25 parts by mass or less. When it is 100 parts by mass or less, good wear resistance tends to be obtained.

[Fourth Invention: Processing Aid]
The rubber composition of the fourth invention contains a processing aid consisting of a fatty acid metal salt and / or a fatty acid amide.

The fatty acid constituting the fatty acid metal salt is not particularly limited, but is saturated or saturated with saturated or unsaturated fatty acids (preferably 6 to 28 carbon atoms (more preferably 10 to 25 carbon atoms, still more preferably 14 to 20 carbon atoms)). (Unsaturated fatty acids), for example, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, behenic acid, nervonic acid and the like. These can be used alone or in admixture of two or more. Of these, saturated fatty acids are preferable, and saturated fatty acids having 14 to 20 carbon atoms are more preferable.

Examples of the metal constituting the fatty acid metal salt include alkali metals such as potassium and sodium, alkaline earth metals such as magnesium, calcium and barium, zinc, nickel and molybdenum. Of these, zinc and calcium are preferable, and zinc is more preferable.

The fatty acid amide may be either a saturated fatty acid amide or an unsaturated fatty acid amide. Examples of the saturated fatty acid amide include N- (1-oxooctadecyl) sarcosin, stearic acid amide, and behenic acid amide. Examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide.

As the processing aid, for example, products such as Structor, Schill + Seiracher, etc. can be used.

In the rubber composition of the fourth invention, the content of the processing aid is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the rubber component. When it is 0.3 parts by mass or more, the effect of blending the processing aid tends to be satisfactorily obtained. The content is preferably 50 parts by mass or less, more preferably 10 parts by mass or less. When it is 50 parts by mass or less, good fuel efficiency tends to be obtained.

[Fifth Invention: Fine Particle Silica]
The rubber composition of the fifth invention contains fine particle silica having a nitrogen adsorption specific surface area of 160 m ² / g or more.

Examples of the fine particle silica include dry silica (anhydrous silica) and wet silica (hydrous silica), but wet silica is preferable because of the large number of silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of the ^{fine particle silica is 160 m 2} / g or more, preferably 180 m ² / g or more, and more preferably 210 m ² / g or more. When it is 160 m ² / g or more, the rubber breaking strength and wear resistance are sufficiently improved. The N ₂ SA is preferably 600 m ² / g or less, more preferably 300 m ² / g or less, and further preferably 260 m ² / g or less. When it is 600 m ² / g or less, the dispersibility is excellent and it is difficult to aggregate, so that workability, fuel efficiency, rubber fracture strength and wear resistance tend to be improved.
In this specification, N ₂ SA of silica is measured according to ASTM D3037-81.

As the fine particle silica, for example, products such as Degussa, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd., Tokuyama Corporation can be used.

In the rubber composition of the fifth invention, the content of the fine particle silica is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 50 parts by mass or more with respect to 100 parts by mass of the rubber component. is there. When it is 5 parts by mass or more, sufficient fuel efficiency and rubber breaking strength tend to be obtained. The content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and further preferably 120 parts by mass or less. When it is 200 parts by mass or less, the workability does not deteriorate, good dispersibility can be ensured, and there is a tendency that fuel efficiency and rubber fracture strength do not decrease.

The rubber compositions of the second to fifth inventions may contain a modified polymer like the rubber compositions of the first invention, and the rubber compositions of the first, third to fifth inventions may contain the modified polymer. The rubber composition of the first, second, fourth, and fifth inventions may contain a resin like the rubber composition of the second invention, and the rubber compositions of the first, second, fourth, and fifth inventions contain a liquid polymer like the rubber composition of the third invention. The rubber compositions of the first to third and fifth inventions may contain the above-mentioned processing aid as in the rubber composition of the fourth invention, and the rubber compositions of the first to fourth inventions may be contained. The rubber composition may contain the fine particle silica as in the rubber composition of the fifth invention.

Further, a silane coupling agent, a modified polymer, a resin, a liquid polymer, the processing aid, and a compounding agent other than the fine particle silica specified in the present application will be described.

[Other combinations]
The rubber composition of the present invention may contain a rubber component other than the above-mentioned modified polymer, that is, a non-modified rubber component.
Examples of the non-modified rubber component include diene rubbers such as isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), and styrene isoprene butadiene rubber (SIBR); chloroprene rubber (CR) and acrylonitrile butadiene rubber (NBR). , Butyl rubber (IIR); and the like. Examples of the isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR (deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc.) and the like. The rubber component may be used alone or in combination of two or more. Of these, SBR, isoprene-based rubber, and BR are preferable, and SBR and BR are more preferable, from the viewpoint that the effects of the present invention can be obtained satisfactorily.

In the rubber composition of the present invention, the content of the isoprene-based rubber (non-modified) is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, based on 100% by mass of the rubber component. is there. When it is 5% by mass or more, good wear resistance tends to be obtained. The content is preferably 95% by mass or less, more preferably 70% by mass or less, and further preferably 50% by mass or less. When it is 95% by mass or less, good low heat generation tends to be obtained.

The SBR (non-denatured) is not particularly limited, and emulsion polymerization SBR (E-SBR), solution polymerization SBR (S-SBR) and the like can be used. The BR is not particularly limited, and is a high cis 1,4-polybutadiene rubber (high cis BR), a butadiene rubber containing 1,2-syndiotactic polybutadiene crystals (SPB-containing BR), and a BR synthesized using a rare earth catalyst (rare earth). BR) and the like.

As the SBR (non-denatured), for example, a solution-polymerized SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Co., Ltd., Asahi Kasei Co., Ltd., Nippon Zeon Co., Ltd., etc. can be used.

In the rubber composition of the present invention, the content of SBR (non-modified) is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, based on 100% by mass of the rubber component. When it is 5% by mass or more, good wear resistance tends to be obtained. The content is preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 80% by mass or less. When it is 95% by mass or less, good low heat generation tends to be obtained.

In the rubber composition of the present invention, the total content of SBR (non-modified) and modified SBR is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass, based on 100% by mass of the rubber component. That is all. When it is 5% by mass or more, good wear resistance tends to be obtained. The content is preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 80% by mass or less. When it is 95% by mass or less, good low heat generation tends to be obtained.

As the BR (non-denatured), for example, products such as Ube Industries, Ltd., JSR Co., Ltd., Asahi Kasei Co., Ltd., and Nippon Zeon Co., Ltd. can be used.

In the rubber composition of the present invention, the content of BR (non-modified) is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, based on 100% by mass of the rubber component. When it is 5% by mass or more, good wear resistance tends to be obtained. The content is preferably 80% by mass or less, more preferably 70% by mass or less. When it is 80% by mass or less, good wet grip performance tends to be obtained.

In the rubber composition of the present invention, the total content of BR (non-modified) and modified BR is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass, based on 100% by mass of the rubber component. That is all. When it is 5% by mass or more, good wear resistance tends to be obtained. The content is preferably 80% by mass or less, more preferably 70% by mass or less. When it is 80% by mass or less, good wet grip performance tends to be obtained.

The rubber composition of the present invention preferably contains carbon black from the viewpoint of wear resistance and the like. As the carbon black, grades such as N110, N220, N330, and N550 can be used.

As carbon black, for example, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nikka Carbon Co., Ltd., Columbia Carbon Co., Ltd., etc. Can be used.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 70 m ² / g or more, more preferably 90 m ² / g or more. The N ₂ SA is preferably 150 m ² / g or less, more preferably 130 m ² / g or less. By setting it above the lower limit, good wear resistance can be obtained, and by setting it below the upper limit, good carbon black dispersion can be obtained, and excellent fuel efficiency tends to be obtained.
The carbon black N ₂ SA can be measured in accordance with JIS-K6217-2: 2001.

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. The content is preferably 200 parts by mass or less, more preferably 50 parts by mass or less, and further preferably 20 parts by mass or less. When the amount is 1 part by mass or more, good wear resistance tends to be obtained, and when the amount is 200 parts by mass or less, good fuel efficiency tends to be obtained.

The rubber composition of the present invention may contain silica other than the above-mentioned fine particle silica.
Examples of other silica include dry silica (silicic anhydride) and wet silica (hydrous silicic acid), but wet silica is preferable because it has many silanol groups.

As other silica, for example, products such as Degussa, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd., Tokuyama Corporation can be used.

The nitrogen adsorption specific surface area (N ₂ SA) of the ^{other silica is preferably 70 m 2} / g or more, and more preferably 100 m ² / g or more. By setting it to 70 m ² / g or more, the wear resistance and the like tend to be improved. The N ₂ SA of the ^{silica is less than 160 m 2} / g.
The nitrogen adsorption specific surface area of the other silica is a value measured by the BET method according to ASTM D3037-81.

In the rubber composition of the present invention, the content of other silica is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, based on 100 parts by mass of the rubber component. By using 5 parts by mass or more, fuel efficiency and the like tend to be improved. The content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, still more preferably 100 parts by mass or less. If it exceeds 200 parts by mass, the balance between workability and fuel efficiency tends to deteriorate.

In the rubber composition of the present invention, the total content of the fine particle silica and other silica is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 50 parts by mass with respect to 100 parts by mass of the rubber component. It is more than a part. When it is 5 parts by mass or more, sufficient fuel efficiency and rubber breaking strength tend to be obtained. The content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and further preferably 120 parts by mass or less. When it is 200 parts by mass or less, the workability does not deteriorate, good dispersibility can be ensured, and there is a tendency that fuel efficiency and rubber fracture strength do not decrease.

In addition to the fine particle silica and other silicas, the rubber composition of the present invention contains calcium carbonate, calcium silicate, magnesium oxide, aluminum oxide, alumina, alumina hydrate, aluminum hydroxide, magnesium hydroxide, magnesium oxide, and sulfuric acid. Other inorganic fillers such as barium, talc, mica, etc. may be included. Even when other inorganic fillers are contained in addition to the fine particle silica and other silicas, the total content of the inorganic fillers is preferably in the above range (total contents of the fine particle silicas and other silicas).

The rubber composition of the present invention preferably contains stearic acid.
As the stearic acid, conventionally known ones can be used, and for example, products such as NOF Corporation, NOF Corporation, Kao Corporation, Wako Pure Chemical Industries, Ltd., and Chiba Fatty Acid Co., Ltd. can be used.

In the rubber composition of the present invention, the content of stearic acid is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, based on 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained satisfactorily.

The rubber composition of the present invention preferably contains zinc oxide.
Conventionally known zinc oxide can be used. For example, products of Mitsui Metal Mining Co., Ltd., Toho Zinc Co., Ltd., HakusuiTech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. Can be used.

In the rubber composition of the present invention, the content of zinc oxide is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, based on 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained better.

The rubber composition of the present invention preferably contains wax.
The wax is not particularly limited, and examples thereof include petroleum wax such as paraffin wax and microcrystalline wax; natural wax such as plant wax and animal wax; and synthetic wax such as a polymer such as ethylene and propylene. Among them, petroleum-based wax is preferable, and paraffin wax is more preferable, because the effect of the present invention can be obtained more satisfactorily.

As the wax, for example, products of Ouchi Shinko Kagaku Kogyo Co., Ltd., Nippon Seiro Co., Ltd., Seiko Kagaku Co., Ltd. and the like can be used.

In the rubber composition of the present invention, the wax content is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, with respect to 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained satisfactorily.

The rubber composition of the present invention preferably contains an anti-aging agent.
Examples of the anti-aging agent include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis (α, α'-dimethylbenzyl) diphenylamine; N. -Isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, N, N'-di-2-naphthyl-p-phenylenediamine, etc. P-Phenylenediamine-based anti-aging agents; quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinolin; 2,6-di-t-butyl-4-methylphenol, Monophenolic anti-aging agents such as styrenated phenol; tetrakis- [methylene-3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] bis, tris, polyphenolic aging such as methane Preventive agents and the like can be mentioned. Of these, p-phenylenediamine-based antiaging agents are preferable, and N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine is more preferable.

As the anti-aging agent, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Co., Ltd. and the like can be used.

In the rubber composition of the present invention, the content of the antiaging agent is preferably 1 part by mass or more, more preferably 3 parts by mass or more, based on 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained satisfactorily.

The rubber composition of the present invention preferably contains oil.
Examples of the oil include process oils, vegetable oils and fats, or mixtures thereof. As the process oil, for example, a paraffin-based process oil, an aroma-based process oil, a naphthenic-based process oil, or the like can be used. Vegetable oils and fats include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pineapple, tall oil, corn oil, rice oil, beni flower oil, sesame oil, Examples thereof include olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. Of these, process oil is preferable.

Examples of oils include Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., Ltd., H & R Co., Ltd., Toyokuni Seiyu Co., Ltd., Showa Shell Sekiyu Co., Ltd., Fuji Kosan Co., Ltd. And other products can be used.

The oil content 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. The content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained better.
The oil content also includes the amount of oil contained in rubber (oil-extended rubber).

The rubber composition of the present invention preferably contains sulfur.
Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur, which are generally used in the rubber industry. These may be used alone or in combination of two or more.

As the sulfur, for example, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Corporation, Flexis Co., Ltd., Nippon Inui Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd. and the like can be used.

The sulfur content is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and further preferably 3 parts by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained satisfactorily.

The rubber composition of the present invention preferably contains a vulcanization accelerator.
Examples of the sulfide accelerator include thiazole-based sulfide-based sulfide accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; tetramethylthiuram disulfide (TMTD). ), Tetrabenzyl thiuram disulfide (TBzTD), tetrakis (2-ethylhexyl) thiuram disulfide (TOT-N) and other thiuram-based sulfide accelerators; N-cyclohexyl-2-benzothiazolesulfenamide, N-t-butyl- 2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide, etc. Sulfenamide-based sulfide accelerator; guanidine-based sulfide accelerators such as diphenylguanidine, dioltotrilguanidine, orthotrilbiguanidine can be mentioned. Of these, sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, and thiuram-based vulcanization accelerators are preferable, and sulfenamide-based vulcanization accelerators are preferable, because the effects of the present invention can be obtained more preferably. , Guanidin-based vulcanization accelerator is more preferable.

As the vulcanization accelerator, for example, products such as Ouchi Shinko Chemical Industry Co., Ltd. and Sanshin Chemical Industry Co., Ltd. can be used.

The content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 3 parts by mass or more, with respect to 100 parts by mass of the rubber component and 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less. Within the above numerical range, the effect of the present invention tends to be obtained satisfactorily.

In addition to the above components, the rubber composition of the present invention may contain additives generally used in the tire industry, and examples thereof include vulcanizing agents other than sulfur (for example, organic cross-linking agents). ..

The organic cross-linking agent is not particularly limited, and examples thereof include maleimide compounds, alkylphenol / sulfur chloride condensates, organic peroxides, amine organic sulfates, and the like. These may be used alone, in combination of two or more, or in combination with sulfur.
For example, the organic cross-linking agent is blended in an amount of 10 parts by mass or less with respect to 100 parts by mass of the rubber component.

The rubber composition of the present invention is produced by a general method. That is, it can be produced by a method of kneading each of the above components with a Banbury mixer, a kneader, an open roll, or the like, and then vulcanizing.

As the kneading conditions, when an additive other than the vulcanizing agent and the vulcanization accelerator is blended, the kneading temperature is usually 50 to 200 ° C., preferably 80 to 190 ° C., and the kneading time is usually 30 seconds. It is ~ 30 minutes, preferably 1 minute to 30 minutes.
When a vulcanizing agent and a vulcanization accelerator are blended, the kneading temperature is usually 100 ° C. or lower, preferably room temperature to 80 ° C. Further, the composition containing the vulcanizing agent and the vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 120 to 200 ° C, preferably 140 to 180 ° C.

The rubber composition of the present invention includes tire members (sidewall, tread (cap tread), base tread, under tread, clinch apex, bead apex, breaker cushion rubber, carcass cord covering rubber, insulation, and chain. It can be suitably used for fur, inner liner; side reinforcing layer of run-flat tire; etc.). Among them, since it has good fuel efficiency, abrasion resistance, wet grip performance and the like, it can be suitably applied to a tread (cap tread).

The pneumatic tire of the present invention is produced by a usual method using the above rubber composition. That is, a rubber composition containing various additives as needed is extruded according to the shape of a tread or the like at the unvulcanized stage, molded by a normal method on a tire molding machine, and then another. After laminating together with the tire members to form an unvulcanized tire, the tire can be manufactured by heating and pressurizing in a vulcanizer.

The tire of the present invention is suitably used as a passenger car tire, a bus tire, a truck tire, a motorcycle tire, a high-performance tire, a competition tire and the like.

シランカップリング剤２：エボニック社製のＳｉ２６６（ビス（３−トリエトキシシリルプロピル）ジスルフィド）
シランカップリング剤３：モメンティブ社製のＮＸＴ（８−メルカプトオクタノイルトリエトキシシラン）
シランカップリング剤４：下記製造例７
シランカップリング剤５：下記製造例８
シランカップリング剤６：下記製造例９
シランカップリング剤７：下記製造例１０
ステアリン酸：日油（株）製のビーズステアリン酸椿
酸化亜鉛：三井金属鉱業（株）製の酸化亜鉛２種
ワックス：大内新興化学工業（株）製のサンノックＮ（パラフィンワックス）
老化防止剤１：大内新興化学工業（株）製のノクラック６Ｃ（Ｎ−（１，３−ジメチルブチル）−Ｎ’−フェニル−ｐ−フェニレンジアミン）
老化防止剤２：川口化学工業（株）製のアンテージＲＤ（ポリ（２，２，４−トリメチル−１，２−ジヒドロキノリン））
脂肪酸金属塩：Ｓｃｈｉｌｌ＋Ｓｅｉｌａｃｈｅｒ社製
脂肪酸アミド：Ｓｃｈｉｌｌ＋Ｓｅｉｌａｃｈｅｒ社製
レジン１：アリゾナケミカル社製のＳｙｌｖａｔｒａｘｘ４４０１（α−メチルスチレンとスチレンとの共重合体、軟化点：８５℃、Ｔｇ：４３℃）
レジン２：ヤスハラケミカル（株）製のＹＳポリスターＭ１２５（水添芳香族変性テルペン樹脂、軟化点：１２５℃、Ｔｇ：６９℃）
レジン３：ヤスハラケミカル（株）製のＹＳレジンＴＯ１２５（芳香族変性テルペン樹脂、軟化点：１２５℃、Ｔｇ：６４℃）
レジン４：丸善石油（株）製のマルカレッツＭ８９０Ａ（ジシクロペンタジエン系樹脂、軟化点：１０５℃）
レジン５：新日鉄化学（株）製のエスクロンＶ１２０（クマロンインデン系樹脂、軟化点：１２０℃）
オイル：出光興産（株）製のダイアナプロセスオイル（アロマオイル）
液状ポリマー１：Ｃｒａｙ ｖａｌｌｅｙ社製のＲｉｃｏｎ１００（液状ＳＢＲ、スチレン量：２５質量％、Ｍｗ：４５００）
液状ポリマー２：（株）クラレ製のＬ−ＳＢＲ−８２０（液状ＳＢＲ、スチレン量：２０質量％、Ｍｗ：８５００）
硫黄：軽井沢硫黄（株）製の粉末硫黄
加硫促進剤１：大内新興化学工業（株）製のノクセラーＮＳ（Ｎ−ｔｅｒｔ−ブチル−２−ベンゾチアゾリルスルフェンアミド）
加硫促進剤２：大内新興化学工業（株）製のノクセラーＤ（Ｎ，Ｎ′−ジフェニルグアニジン）
加硫促進剤３：三新化学工業（株）製のサンセラーＴＢＺＴＤ（テトラベンジルチウラムジスルフィド） The present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.
The various chemicals used in the examples will be described below.
NR: RSS # 3
SBR1: the following Production Example 1 (modified, styrene content: 25 wt%, vinyl content: 60 ^{wt%, Mw: 1.6 × 10 5} )
SBR2: solution polymerization SBR (unmodified, styrene content: 40 wt%, vinyl content: 14 ^{wt%, Mw: 12 × 10 5} )
SBR3: solution polymerization SBR (unmodified, styrene content: 39 wt%, vinyl content: 40 ^{wt%, Mw: 9.2 × 10 5} )
SBR4: the following Production Example 2 (modified, styrene content: 35 wt%, vinyl content: 50 ^{wt%, Mw: 6.7 × 10 5} )
SBR5: the following Production Example 3 (modified, styrene content: 25 wt%, vinyl content: 60 ^{wt%, Mw: 3.3 × 10 5} )
SBR6: the following Production Example 4 (modified, styrene content: 10 wt%, vinyl content: 40 wt%, Mw: 2.1 × ¹⁰ 5)
SBR7: the following Production Example 5 (modified, styrene content: 35 wt%, vinyl content: 40 wt%, Mw: 9 × ¹⁰ 5)
BR1: the following Production Example 6 (modification, the amount of vinyl: 13 ^{wt%, Mw: 4.4 × 10 5} )
BR2: BR150B manufactured by Ube Industries, Ltd. (non-denatured, cis content: 97% by mass)
Carbon black: Show black N220 manufactured by Cabot Japan Co., Ltd. (N ₂ SA: 111m ² / g, DBP absorption amount: 115ml / 100g)
Silica 1: Evonik 9100GR (N ₂ SA: ^{235m 2} / g)
Silica 2: VN3 manufactured by Evonik (N ₂ SA: 175m ² / g)
Silica 3: 115GR manufactured by Solvay Japan Co., Ltd. (N ₂ SA: 115m ² / g)
Silane coupling agent 1: Si363 manufactured by Evonik (silane coupling agent represented by the following formula)

Silane coupling agent 2: Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Evonik Industries, Inc.
Silane coupling agent 3: NXT (8-mercaptooctanoyltriethoxysilane) manufactured by Momentive.
Silane coupling agent 4: Production example 7 below
Silane coupling agent 5: Production example 8 below
Silane coupling agent 6: The following production example 9
Silane coupling agent 7: Production example 10 below
Stearic acid: Beads manufactured by NOF Corporation Tsubaki stearic acid Zinc oxide: Zinc oxide type 2 wax manufactured by Mitsui Metal Mining Co., Ltd .: Sannock N (paraffin wax) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
Anti-aging agent 1: Nocrack 6C (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
Anti-aging agent 2: Antage RD (Poly (2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Kawaguchi Chemical Industry Co., Ltd.
Fatty acid metal salt: Schill + Seiracher fatty acid amide: Schill + Seiracher resin 1: Sylvatraxx4401 (copolymer of α-methylstyrene and styrene, softening point: 85 ° C, Tg: 43 ° C)
Resin 2: YS Polystar M125 manufactured by Yasuhara Chemical Co., Ltd. (hydrogenated aromatic-modified terpene resin, softening point: 125 ° C, Tg: 69 ° C)
Resin 3: YS resin TO125 manufactured by Yasuhara Chemical Co., Ltd. (aromatically modified terpene resin, softening point: 125 ° C, Tg: 64 ° C)
Resin 4: Marcaretz M890A manufactured by Maruzen Petroleum Co., Ltd. (dicyclopentadiene resin, softening point: 105 ° C)
Resin 5: Esclon V120 manufactured by Nippon Steel Chemical Co., Ltd. (Kumaron inden resin, softening point: 120 ° C)
Oil: Diana process oil (aroma oil) manufactured by Idemitsu Kosan Co., Ltd.
Liquid polymer 1: Ricon 100 manufactured by Cray valley (liquid SBR, amount of styrene: 25% by mass, Mw: 4500)
Liquid polymer 2: L-SBR-820 manufactured by Kuraray Co., Ltd. (Liquid SBR, styrene amount: 20% by mass, Mw: 8500)
Sulfur: Powdered sulfur vulcanization accelerator manufactured by Karuizawa Sulfur Co., Ltd. 1: Noxeller NS (N-tert-butyl-2-benzothiazolyl sulfeneamide) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
Vulcanization accelerator 2: Noxeller D (N, N'-diphenylguanidine) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
Vulcanization Accelerator 3: Sunseller TBZTD (Tetrabenzyl Thiram Disulfide) manufactured by Sanshin Chemical Industry Co., Ltd.

(Manufacturing Example 1)
The inside of the stainless polymerization reactor having an internal volume of 20 liters was washed, dried, replaced with dry nitrogen, hexane (specific gravity 0.68 g / cm ³ ) 10.2 kg, 1,3-butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and 5.0 ml of ethylene glycol diethyl ether were charged into the polymerization reactor. Next, 13.1 mmol of n-butyllithium was added as an n-hexane solution to initiate polymerization. The stirring speed was 130 rpm, the temperature inside the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g. Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 11.1 mmol of 3-diethylaminopropyltriethoxysilane was added, and the mixture was stirred for 15 minutes. 20 ml of a hexane solution containing 0.54 ml of methanol was added to the polymer solution, and the polymer solution was further stirred for 5 minutes. 2-tert-Butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenylacrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer GM) in the polymer solution 1. Add 8 g, 0.9 g of pentaerythrityltetrakis (3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer TP-D), and then add SBR1 from the polymer solution by steam stripping. Recovered.

(Manufacturing Example 2)
18 L of n-hexane, 800 g of styrene (manufactured by Kanto Chemical Co., Inc.), 1200 g of butadiene, and 1.1 mmol of tetramethylethylenediamine were added to a 30 L pressure-resistant container sufficiently substituted with nitrogen, and the temperature was raised to 40 ° C. Next, 1.8 mL of 1.6 M butyllithium (manufactured by Kanto Chemical Co., Inc.) was added, the temperature was raised to 50 ° C., and the mixture was stirred for 3 hours. Next, 4.1 mL of the above terminal denaturing agent was added, and the mixture was stirred for 30 minutes. After adding 15 mL of methanol and 0.1 g of 2,6-tert-butyl-p-cresol to the reaction solution, the mixture was stirred for 10 minutes. Then, the agglomerates were recovered from the polymer solution by steam stripping treatment. The obtained aggregate was dried under reduced pressure for 24 hours to obtain SBR4.

(Manufacturing Example 3)
In Production Example 1, the amount of material charged was changed and SBR5 was recovered.

(Manufacturing Example 4)
In Production Example 1, the amount of material charged was changed and SBR6 was recovered.

(Manufacturing Example 5)
In Production Example 2, the amount of material charged was changed and SBR7 was recovered.

(Manufacturing Example 6)
Under a nitrogen atmosphere, add 23.6 g of 3- (N, N-dimethylamino) propyltrimethoxysilane (manufactured by Azumax) to a 100 ml volumetric flask, and add anhydrous hexane (manufactured by Kanto Chemical Co., Ltd.) to make the total volume 100 ml. To prepare a terminal modifier.
18 L of n-hexane, 2000 g of butadiene, and 2 mmol of TMEDA were added to a 30 L pressure-resistant container sufficiently substituted with nitrogen, and the temperature was raised to 60 ° C. Next, 10.3 mL of butyllithium was added, the temperature was raised to 50 ° C., and the mixture was stirred for 3 hours. Next, 11.5 mL of the above terminal denaturing agent was added, and the mixture was stirred for 30 minutes. After adding 15 mL of methanol and 0.1 g of 2,6-tert-butyl-p-cresol to the reaction solution, the reaction solution was placed in a stainless steel container containing 18 L of methanol to recover the aggregates. The obtained aggregate was dried under reduced pressure for 24 hours to obtain BR1.

(Production Example 7: Synthesis of silane coupling agent 4 (x = 2.2, m = 8, R ^{1 to} R ⁶ = OCH ₂ CH ₃ ))
Anhydrous sodium sulfide 78.0 g (1.0 mol), sulfur 38.5 g (1.2 mol) and ethanol 480 g were placed in a 2 L separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer. It was heated to 80 ° C. 622 g (2.0 mol) of 8-chlorooctyltriethoxysilane was added dropwise thereto, and the mixture was heated and stirred at 80 ° C. for 10 hours. This reaction solution was pressure-filtered using a filter plate to obtain a filtrate from which the salt produced as the reaction proceeded was removed. The obtained filtrate was heated to 100 ° C. and ethanol was distilled off under a reduced pressure of 10 mmHg or less to obtain a silane coupling agent 4 as a reaction product.
The obtained silane coupling agent 4 has a sulfur content of 10.8% by mass (0.34 mol) and a silicon content of 8.7% by mass (0.31 mol) in the compound, and contains sulfur atoms. The number / number of silicon atoms was 1.1.

(Production Example 8: Synthesis of silane coupling agent 5 (x = 2.0, m = 8, R ^{1 to} R ⁶ = OCH ₂ CH ₃ ))
Synthesis was carried out in the same procedure as in Production Example 7 except that the amount of sulfur was changed to 32.1 g (1.0 mol) to obtain a silane coupling agent 5 as a reaction product.
The obtained silane coupling agent 5 has a sulfur content of 10.0% by mass (0.31 mol) and a silicon content of 8.8% by mass (0.31 mol) in the compound, and contains sulfur atoms. The number / number of silicon atoms was 1.0.

(Production Example 9: Synthesis of silane coupling agent 6 (x = 2.4, m = 8, R ^{1 to} R ⁶ = OCH ₂ CH ₃ ))
Synthesis was carried out in the same procedure as in Production Example 7 except that the amount of sulfur was changed to 45.0 g (1.4 mol) to obtain a silane coupling agent 6 as a reaction product.
The obtained silane coupling agent 6 has a sulfur content of 11.9% by mass (0.37 mol) and a silicon content of 8.7% by mass (0.31 mol) in the compound, and contains sulfur atoms. The number / number of silicon atoms was 1.2.

(Production Example 10: Synthesis of silane coupling agent 7 (x = 2.2, m = 8, R ¹ , R ² , R ⁴ , R ⁵ = OCH ₂ CH ₃ , R ³ , R ⁶ = CH ₃ ))
A silane coupling agent was synthesized as a reaction product by the same procedure as in Production Example 7 except that 562 g (2.0 mol) of 8-chlorooctyldiethoxymethylsilane was used instead of 8-chlorooctyltriethoxysilane. I got 7.
The obtained silane coupling agent 7 has a sulfur content of 11.0% by mass (0.34 mol) and a silicon content of 8.7% by mass (0.31 mol) in the compound, and contains sulfur atoms. The number / number of silicon atoms was 1.1.

<Examples and Comparative Examples>
According to the formulation shown in Tables 1 to 5, materials other than sulfur and the vulcanization accelerator were kneaded at 160 ° C. for 3 minutes using a 1.7 L Banbury mixer to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and the mixture was kneaded for 3 minutes under the condition of 80 ° C. using an open roll to obtain an unvulcanized rubber composition.
The obtained unvulcanized rubber composition is formed into a tread shape and bonded together with other tire members to form an unvulcanized tire, which is press-vulcanized for 15 minutes under the condition of 170 ° C. to obtain a test tire (test tire). Size: 195 / 65R15) was manufactured.

The obtained unvulcanized rubber composition and test tire were evaluated as follows. The results are shown in Tables 1-5. Tables 1 to 5 correspond to the first to fifth inventions, respectively, and the reference comparative examples in Tables 1 to 5 are Comparative Examples 1-1, 2-1, 3-1, 4-1 and 5-1 respectively. did.

(Workability (Moony viscosity))
_{For the unvulcanized rubber composition, the Mooney viscosity (ML 1 + 4} ) was measured at 130 ° C. using MV202 manufactured by Shimadzu Corporation based on JIS K 6301. The Mooney viscosity of each formulation was expressed as an index (processability index), with the Mooney viscosity value of the standard comparative example as 100. The larger the index, the better the workability.

(Fuel efficiency)
A sample taken from the tread of a test tire was subjected to a loss tangent (tanδ) at 60 ° C. under the conditions of initial strain of 10%, dynamic strain of 2%, and frequency of 10 Hz using a viscoelastic spectrometer manufactured by Ueshima Seisakusho Co., Ltd. ) Was measured. The tan δ of the standard comparative example was set to 100, and the index was displayed by the following formula (fuel efficiency index). The larger the index, the better the fuel efficiency.
(Fuel efficiency index) = (tan δ of standard comparative example) / (tan δ of each formulation) × 100

(Abrasion resistance)
A sample collected from the tread of a test tire was measured for wear using a Ramborn type wear tester under the conditions of room temperature, load load of 1.0 kgf, and slip ratio of 30%, and was expressed as an index by the following formula (withstand). Abrasion index). The larger the index, the better the wear resistance.
(Abrasion resistance index) = (Abrasion amount of standard comparative example) / (Abrasion amount of each formulation) x 100

(Wet grip performance)
Samples taken from the tread of the test tire were measured for viscoelasticity parameters in torsion mode using a viscoelasticity tester (ARES) manufactured by Leometrics Scientific. Tan δ was measured at 0 ° C. at a frequency of 10 Hz and a strain of 1%. The tan δ of the standard comparative example was set to 100, and the index was displayed by the following formula (wet grip performance index). The larger the index, the better the wet grip performance.
(Wet grip figure of merit) = (tan δ of standard comparative example) / (tan δ of each formulation) × 100

From Tables 1 to 5, examples containing the silane coupling agent specific to the present application and at least one of a modified polymer, a resin, a liquid polymer, a processing aid, and fine particle silica have workability, wet grip performance, and low fuel consumption. It was also clarified that the performance balance of abrasion resistance was remarkably improved.

Claims (6)

A rubber composition for a tire containing a modified polymer and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more and 12 or less carbon atoms connecting the alkoxysilyl group and the sulfur atom. A rubber composition for a tire containing a resin and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more and 12 or less carbon atoms connecting the alkoxysilyl group and the sulfur atom. A rubber composition for a tire containing a liquid polymer and a silane coupling agent containing an alkoxysilyl group and a sulfur atom and having 6 or more and 12 or less carbon atoms connecting the alkoxysilyl group and the sulfur atom. Silane coupling containing a processing aid consisting of a fatty acid metal salt and / or a fatty acid amide, an alkoxysilyl group and a sulfur atom, and having 6 or more and 12 or less carbon atoms connecting the alkoxysilyl group and the sulfur atom. A rubber composition for a tire containing an agent. Silane coupling containing fine particle silica with a nitrogen adsorption specific surface area of 160 m ² / g or more, an alkoxysilyl group and a sulfur atom, and 6 or more and 12 or less carbon atoms connecting the alkoxysilyl group and the sulfur atom. A rubber composition for a tire containing an agent. A pneumatic tire produced by using the rubber composition according to any one of claims 1 to 5.