JP2018076469A - Rubber composition, method for producing rubber composition and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition well improved in processability without deteriorating low fuel consumption, a tire comprising a tire member made of the rubber composition, and a method for producing the rubber composition.SOLUTION: There are provided a rubber composition which comprises a predetermined amount of silica, a predetermined amount of an amine-based antiaging agent and at least one silane coupling agent selected from the group consisting of a silane coupling agent 1 having a carbonylthio group (-S-C(=O)-) and having no mercapto group and a silane coupling agent 2 having a mercapto group based on 100 pts.mass of a rubber component containing a copolymer obtained by copolymerization of an aromatic vinyl compound and a conjugated diene compound and is obtained by kneading the rubber component and all of the silane coupling agents, followed by kneading the amine-based antiaging agent in another kneading step, a tire comprising a tire member made of the rubber composition, and a method for producing the rubber composition.SELECTED DRAWING: None

Description

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

  Conventionally, as a rubber composition for automobile tires, a rubber composition containing a conjugated diene polymer such as polybutadiene or butadiene-styrene copolymer and a filler such as carbon black or silica is used. In recent years, due to increasing interest in environmental issues, there has been a strong demand for lower fuel consumption for automobiles, and rubber compositions used for automobile tires are also required to have excellent fuel efficiency. .

  As a method for improving fuel economy, use of a silane coupling agent having a mercapto group highly reactive with silica (mercapto silane coupling agent) has been studied. However, mercapto-based silane coupling agents tend to deteriorate processability while obtaining good fuel efficiency. Further, Patent Document 1 discloses a technique for improving fuel economy, wet grip performance and steering stability by using protected mercaptosilane as a silane coupling agent, but it ensures good workability. In Patent Document 2, a diene rubber (modified rubber) modified with N-methylpyrrolidone has a carbonylthio group (—S—C (═O) —) and a mercapto group (—SH). There has been proposed a method in which a silane coupling agent that is not used and a silane coupling agent having a mercapto group are sequentially kneaded in separate steps.

JP 2008-101158 A JP 2012-140508 A

  However, there is still room for study in improving processability when using a silane coupling agent having a mercapto group or a silane coupling agent having a carbonylthio group and not having a mercapto group.

  Accordingly, the present invention provides a rubber composition that solves the above-mentioned problems and that has improved processability satisfactorily without reducing fuel efficiency, a method for producing the rubber composition, and a tire member that is composed of the rubber composition. An object is to provide a tire provided.

  As a result of intensive studies, the inventor contains a rubber component containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, a predetermined amount of silica and an amine anti-aging agent, and a predetermined amount. In the rubber composition using the silane coupling agent, the deterioration of workability is suppressed by kneading the amine-based anti-aging agent in the subsequent step separately from the kneading step of the silane coupling agent, and the above-mentioned problem As a result, the present invention was completed.

［式中、Ｒ¹⁰¹は、−Ｃｌ、−Ｂｒ、−ＯＲ¹⁰⁶、−Ｏ（Ｏ＝）ＣＲ¹⁰⁶、−ＯＮ＝ＣＲ¹⁰⁶Ｒ¹⁰⁷、−ＮＲ¹⁰⁶Ｒ¹⁰⁷および−（ＯＳｉＲ¹⁰⁶Ｒ¹⁰⁷）_h（ＯＳｉＲ¹⁰⁶Ｒ¹⁰⁷Ｒ¹⁰⁸）から選択される一価の基（ここで、Ｒ¹⁰⁶、Ｒ¹⁰⁷およびＲ¹⁰⁸は同一でも異なっていても良く、各々水素原子または炭素数１〜１８の一価の炭化水素基であり、ｈは平均値が１〜４である。）であり、Ｒ¹⁰²はＲ¹⁰¹、水素原子または炭素数１〜１８の一価の炭化水素基、Ｒ¹⁰³は、Ｒ¹⁰¹、Ｒ¹⁰²または水素原子、Ｒ¹⁰⁴は、炭素数１〜１８の二価の炭化水素基、Ｒ¹⁰⁵は炭素数１〜１８の一価の炭化水素基である］、
［５］シランカップリング剤２を含有し、かつシランカップリング剤２が、下記式（２−１）で表される結合単位Ａと下記式（２−２）で表される結合単位Ｂとを含むシランカップリング剤である上記［１］〜［４］のいずれかに記載のゴム組成物

（式中、ｘは１以上の整数、ｙは１以上の整数であり、Ｒ²⁰¹は水素、ハロゲン、直鎖もしくは分岐鎖の炭素数１〜３０のアルキル基、直鎖もしくは分岐鎖の炭素数２〜３０のアルケニル基、直鎖もしくは分岐鎖の炭素数２〜３０のアルキニル基、または該アルキル基の末端の水素が水酸基もしくはカルボキシル基で置換されたものであり、Ｒ²⁰²は、直鎖もしくは分岐鎖の炭素数１〜３０のアルキレン基、直鎖もしくは分岐鎖の炭素数２〜３０のアルケニレン基、または直鎖もしくは分岐鎖の炭素数２〜３０のアルキニレン基であり、あるいはＲ²⁰¹とＲ²⁰²とで環構造を形成してもよい。）、
［６］上記［１］〜［５］のいずれかに記載のゴム組成物により構成されるタイヤ部材を備えるタイヤ、
［７］タイヤ部材がトレッドである上記［６］記載のタイヤ、ならびに
［８］芳香族ビニル化合物および共役ジエン化合物を共重合して得られた共重合体を含むゴム成分１００質量部に対し、シリカを６０〜２００質量部、好ましくは６５〜１５０質量部、より好ましくは７０〜１３０質量部、アミン系老化防止剤を１．５〜５．０質量部、好ましくは２．０〜４．０質量部含有し、カルボニルチオ基（−Ｓ−Ｃ（＝Ｏ）−）を有しかつメルカプト基（−ＳＨ）を有しないシランカップリング剤１およびメルカプト基を有するシランカップリング剤２からなる群より選択される少なくとも１つのシランカップリング剤を含有するゴム組成物の製造方法であって、ゴム成分と全部のシランカップリング剤とを混練りする工程１と、工程１の後にアミン系老化防止剤を混練りする工程２を含むゴム組成物の製造方法
に関する。 That is, the present invention
[1] Silica is 60 to 200 parts by mass, preferably 65 to 150 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of a rubber component containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound. Contains 70 to 130 parts by weight, 1.5 to 5.0 parts by weight, preferably 2.0 to 4.0 parts by weight of an amine-based antioxidant, and contains a carbonylthio group (—S—C (═O) — And a rubber composition containing at least one silane coupling agent selected from the group consisting of a silane coupling agent 1 having no mercapto group (-SH) and a silane coupling agent 2 having a mercapto group. A rubber composition obtained by kneading an amine anti-aging agent in a separate kneading step after kneading the rubber component and all silane coupling agents,
[2] The rubber composition according to the above [1], wherein the discharge temperature of the kneading step for mixing the amine-based antioxidant is 110 to 140 ° C, preferably 120 to 135 ° C.
[3] The above [1] or [2], wherein the total content of the silane coupling agent 1 and the silane coupling agent 2 is 1 to 12 parts by mass, preferably 4 to 10 parts by mass with respect to 100 parts by mass of silica. The rubber composition according to the description,
[4] The rubber according to any one of [1] to [3], which contains the silane coupling agent 1 and the silane coupling agent 1 is a silane coupling agent represented by the following formula (1): Composition

[Wherein R ¹⁰¹ represents —Cl, —Br, —OR ¹⁰⁶ , —O (O═) CR ¹⁰⁶ , —ON═CR ¹⁰⁶ R ¹⁰⁷ , —NR ¹⁰⁶ R ¹⁰⁷ and — (OSiR ¹⁰⁶ R ¹⁰⁷ ) _h ( A monovalent group selected from OSiR ¹⁰⁶ R ¹⁰⁷ R ¹⁰⁸ , wherein R ¹⁰⁶ , R ¹⁰⁷ and R ¹⁰⁸ may be the same or different and each is a hydrogen atom or a monovalent carbon atom having 1 to 18 carbon atoms. are a hydrogen group, h is the average value of 1~4.), R ¹⁰² is R ^101, a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ¹⁰³ is, R ^101, R ¹⁰² or a hydrogen atom, R ¹⁰⁴ is a divalent hydrocarbon group having 1 to 18 carbon atoms, and R ¹⁰⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms]
[5] A silane coupling agent 2 is contained, and the silane coupling agent 2 includes a binding unit A represented by the following formula (2-1) and a binding unit B represented by the following formula (2-2). The rubber composition according to any one of the above [1] to [4], which is a silane coupling agent containing

(Wherein x is an integer of 1 or more, y is an integer of 1 or more, R ²⁰¹ is hydrogen, halogen, a linear or branched alkyl group having 1 to 30 carbon atoms, or a linear or branched carbon number. A alkenyl group having 2 to 30 carbon atoms, a linear or branched alkynyl group having 2 to 30 carbon atoms, or a hydrogen atom substituted at the terminal of the alkyl group with a hydroxyl group or a carboxyl group, and R ²⁰² is a straight chain or A branched chain alkylene group having 1 to 30 carbon atoms, a straight chain or branched chain alkenylene group having 2 to 30 carbon atoms, or a straight chain or branched chain alkenylene group having 2 to 30 carbon atoms, or R ²⁰¹ and R ²⁰² may form a ring structure).
[6] A tire comprising a tire member composed of the rubber composition according to any one of [1] to [5],
[7] The tire according to [6] above, wherein the tire member is a tread, and [8] 100 parts by mass of a rubber component containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound. 60 to 200 parts by mass of silica, preferably 65 to 150 parts by mass, more preferably 70 to 130 parts by mass, and 1.5 to 5.0 parts by mass of amine-based antioxidant, preferably 2.0 to 4.0. The group which consists of silane coupling agent 1 which has a carbonylthio group (-S-C (= O)-) and does not have a mercapto group (-SH), and silane coupling agent 2 which has a mercapto group containing a mass part A method for producing a rubber composition containing at least one silane coupling agent selected from the step 1, wherein the rubber component and all silane coupling agents are kneaded, and after step 1 The method for producing a rubber composition comprising kneading an amine-based antioxidant step 2.

  According to the present invention, a predetermined amount of silica and a predetermined amount of amine-based anti-aging agent are contained in 100 parts by mass of a predetermined rubber component, and in a rubber composition using a predetermined silane coupling agent, amine-based anti-aging is prevented. In addition to the silane coupling agent kneading step, the agent can be kneaded in a later step to provide a rubber composition with good processability as well as low fuel consumption. Moreover, the tire provided with the various tire members comprised with the rubber composition, and the manufacturing method of the rubber composition can be provided.

  The rubber composition of the present invention comprises 60 to 200 parts by mass of silica and an amine-based antioxidant for 100 parts by mass of a rubber component containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound. Is contained in an amount of 1.5 to 5.0 parts by mass. Thereby, rubber fracture strength and wear resistance can be improved satisfactorily. Further, the rubber composition of the present invention further includes a silane coupling agent 1 having a carbonylthio group (—S—C (═O) —) and not having a mercapto group, and a silane coupling agent 2 having a mercapto group. At least one silane coupling agent selected from the group consisting of: Thereby, low fuel consumption can be made favorable. Furthermore, in the rubber composition of the present invention, the mixing step of the amine-based anti-aging agent and the silane coupling agent is a separate step, and the amine-based anti-aging agent is mixed in a step after all the silane coupling agents. The rubber breaking strength and processability can be improved remarkably and synergistically without lowering the fuel efficiency, and good fuel economy, rubber breaking strength and processability can be obtained.

  The rubber composition of the present invention uses a rubber component containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound.

  Examples of the aromatic vinyl compound include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene, and the like. . These may be used alone or in combination of two or more. Among these, styrene is particularly preferable from the viewpoint of practical use such as the availability of monomers and the reason that the effects of the present invention can be obtained more suitably.

  Examples of the conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, and the like. These may be used alone or in combination of two or more. Among these, 1,3-butadiene and isoprene are preferable, and 1,3-butadiene is more preferable, from the viewpoint of practical aspects such as availability of monomers and the effect that the effects of the present invention can be obtained more suitably.

  The copolymer obtained by copolymerizing the aromatic vinyl compound and the conjugated diene compound may be a hydrogenated product (hydrogenated copolymer).

  The weight average molecular weight (Mw) of the copolymer is preferably 200,000 or more, and more preferably 400,000 or more. By setting Mw to 200,000 or more, good rubber breaking strength and wear resistance tend to be obtained. The Mw of the copolymer is preferably 2,000,000 or less, more preferably 1,000,000 or less, and further preferably 700,000 or less. By making Mw 2,000,000 or less, there is a tendency that better workability is obtained.

  In this specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are gel permeation chromatograph (GPC) (GPC-8000 series manufactured by Tosoh Corporation), detector: differential refractometer, column : It can be determined by standard polystyrene conversion based on the measured value by TSKEL SUPERMALTPORE HZ-M manufactured by Tosoh Corporation.

  The glass transition temperature (Tg) of the copolymer is preferably −50 ° C. or higher, more preferably −40 ° C. or higher, still more preferably −35 ° C. or higher, and most preferably −30 ° C. or higher. By setting Tg to −50 ° C. or higher, there is a tendency that better rubber breaking strength can be obtained.

  In addition, the glass transition temperature (Tg) of a copolymer can be measured by the method as described in the below-mentioned Example.

  The content of the copolymer obtained by copolymerizing the aromatic vinyl compound and the conjugated diene compound in the total rubber component is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 75% by mass or more. . When the content of the copolymer in the total rubber component is 60% by mass or more, the wet grip performance tends to be sufficiently ensured. Moreover, 95 mass% or less is preferable and, as for content in all the rubber components of a copolymer, 90 mass% or less is more preferable. By setting the content of the copolymer in the total rubber component to 95% by mass or less, the wear resistance tends to be ensured.

  The copolymer obtained by copolymerizing the aromatic vinyl compound and the conjugated diene compound is preferably styrene butadiene rubber (SBR). The SBR is not particularly limited, and examples thereof include emulsion polymerization SBR (E-SBR), solution polymerization SBR (S-SBR) and the like. These SBRs are modified with a modifier (modified SBR), and these SBRs. A hydrogenated product (hydrogenated SBR) or the like can also be used. For example, S-SBR can be used in consideration of compatibility between wet grip performance and rolling resistance performance.

  As the modified SBR, those obtained by treating SBR generally used in the tire industry with a modifying agent can be used. Examples of the modifier include 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylethyldimethoxysilane, 3-aminopropyltrimethoxysilane, and 3- (2-aminoethylamino) propyl. Examples include trimethoxysilane, tin tetrachloride, butyltin trichloride, N-methylpyrrolidone and the like. These may be used alone or in combination of two or more.

  As a method for modifying SBR with the above modifier, a conventionally known method such as the method described in JP-B-6-53768, JP-B-6-57767, JP-T2003-514078, or the like is used. Can do. 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 in which a modifier is added to the SBR solution for reaction.

  The vinyl content of SBR is preferably 30% by mass or more, more preferably 50% by mass or more. If it is less than 30% by mass, fuel economy and grip properties tend to deteriorate. The vinyl content is preferably 90% by mass or less, more preferably 70% by mass or less. If it exceeds 90% by mass, the fuel efficiency tends to deteriorate. In the present invention, the vinyl content of SBR can be measured by infrared absorption spectrum analysis.

The styrene content of SBR is preferably 5% by mass or more, more preferably 10% by mass or more. If it is less than 5% by mass, sufficient rigidity may not be obtained. The styrene content is preferably 60% by mass or less, more preferably 50% by mass or less. If it exceeds 60% by mass, the heat build-up will remarkably increase and the fuel efficiency tends to decrease. In the present invention, the styrene content of SBR is calculated by H ¹ -NMR measurement.

  Examples of other rubber components that can be used in addition to the copolymer include polybutadiene rubber (BR), butadiene isoprene copolymer rubber, and butyl rubber. Moreover, natural rubber (NR), an ethylene propylene copolymer, an ethylene octene copolymer, etc. can be mentioned. Two or more of these rubber components may be used in combination.

  When BR is included as a rubber component, the BR is not particularly limited, and 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), rare earth-based BR, and the like, and these various BRs may be used alone or in combination of two or more. Among them, high cis BR is preferable because it has a high effect of improving wear resistance and good fuel economy. High cis BR is a butadiene rubber having a cis 1,4 bond content of 90% by mass or more. In the present invention, the vinyl content (1,2-bonded butadiene unit amount) and cis-1,4 bond content of high-cis BR, modified BR, and rare earth BR can be measured by infrared absorption spectrum analysis.

  The high cis butadiene rubber (high cis BR) has a cis content of 90% or more. For example, BR730 and BR51 manufactured by JSR Corporation, BR1220 manufactured by Nippon Zeon Co., Ltd., and BR130B manufactured by Ube Industries, Ltd. , BR150B, BR710 and the like. Among the high cis BRs, those having a cis 1,4-bond content of 95% or more are more preferable. These may be used alone or in combination of two or more. By containing the high cis BR, it is possible to improve the wear resistance and to suppress the rubber curing at a low temperature.

  When BR is contained as a rubber component, the content of BR in all rubber components is preferably 5% by mass or more, and more preferably 10% by mass or more. When the content of BR in all rubber components is 5% by mass or more, sufficient wear resistance tends to be ensured. Further, the content of BR in all rubber components is preferably less than 40% by mass, and more preferably less than 35% by mass. When the content of BR in all rubber components is less than 35% by mass, there is a tendency that it is easy to achieve both workability and wet grip performance.

  The silica is not particularly limited, and examples thereof include silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), and the like, for the reason that there are many silanol groups. Silica prepared by a wet method is preferred.

Nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably not less than 45 m ² / g, more preferably at least ^{55m 2 / g, 60m 2 /} g or more and more preferably, 100 m ² / g or more and particularly preferably, 150 meters ² / G or more is most preferable. By setting the N ₂ SA of silica to 45 m ² / g or more, sufficient reinforcement can be obtained, and the fracture strength and wear resistance can be further improved. The N ₂ SA of the silica is preferably 350 meters ² / g or less, more preferably 300 meters ² / g, more preferably from 270 meters ² / g or less, particularly preferably 220 m ² / g. When the N ₂ SA of silica is 350 m ² / g or less, the dispersion of silica is facilitated, and better fuel efficiency can be obtained. Here, N ₂ SA of silica in the present specification is a value measured by the BET method according to ASTM D3037-81.

  The content of silica is 60 parts by mass or more, preferably 65 parts by mass or more, and more preferably 70 parts by mass or more with respect to 100 parts by mass of the rubber component. When the content of silica is less than 60 parts by mass, the effect of blending silica cannot be sufficiently obtained, and the fuel economy and wear resistance tend to deteriorate. Moreover, content of a silica is 200 mass parts or less with respect to 100 mass parts of rubber components, 150 mass parts or less are preferable, 130 mass parts or less are more preferable, 110 mass parts or less are more preferable. If the total silica content exceeds 200 parts by mass, it will be difficult to disperse the silica into the rubber, and the fuel economy, processability and wear resistance will tend to deteriorate.

  Although it does not specifically limit as an amine type anti-aging agent, For example, alkylated diphenylamines, such as naphthylamine type | system | groups, such as N-phenyl- 1-naphthylamine, octylated diphenyl, 4,4'-bis ((alpha), (alpha), (alpha) Dimethylamines such as -dimethylbenzyl) diphenylamine and p- (p-toluenesulfonylamide) diphenylamine; N, N'-di-2-naphthyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N -Phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine, N-phenyl-N'-(3-methacryloyloxy-2-hydroxy P-phenylenediamine such as propyl) -p-phenylenediamine 1 type (s) or 2 or more types of aromatic secondary amine type anti-aging agents, such as a system, are mentioned.

  The content of the amine-based anti-aging agent is 1.5 parts by mass or more and preferably 2.0 parts by mass or more with respect to 100 parts by mass of the rubber component. When the content of the amine-based anti-aging agent is less than 1.5 parts by mass, there is a fear that the destructive characteristics cannot be improved, and the ozone resistance tends not to ensure marketability. Moreover, content of an amine type anti-aging agent is 5.0 mass parts or less with respect to 100 mass parts of rubber components, 4.0 mass parts or less are preferable, and 3.0 mass parts or less are more preferable. When the content of the amine-based anti-aging agent exceeds 5.0 parts by mass, the anti-aging agent is deposited on the surface, the rubber properties may be deteriorated, and there is a tendency to become a complaint due to discoloration.

  The rubber composition in the present invention can be used together with an anti-aging agent other than the amine-based anti-aging agents mentioned above. As these, conventionally known ones can be used, and examples thereof include quinoline-based antioxidants, monophenol-based antioxidants, bis, tris, polyphenol-based antioxidants, and the like. Examples of the quinoline antioxidant include 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 6-anilino-2, Examples include 2,4-trimethyl-1,2-dihydroquinoline and poly-2,2,4-trimethyl-1,2-dihydroquinoline. With respect to the phenolic anti-aging agent, the monophenolic anti-aging agent includes 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6- Di-tert-butylphenol, 1-oxy-3-methyl-4-isopropylbenzene, 2-methyl-4,6-bis [(octylthio) methyl] phenol, butylhydroxyanisole, 2,4-dimethyl-6-tert- Examples thereof include butylphenol, n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-tert-butylphenyl) propionate, styrenated phenol, and phenol derivatives. Examples of the bisphenol-based, trisphenol-based, and polyphenol-based antiaging agents include 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl- 6-tert-butylphenol), 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenol), 1,1′-bis- (4-hydroxyphenyl) -cyclohexane, tetrakis- [methylene-3 -(3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane and the like. Of these, it is preferable to use a quinoline anti-aging agent in combination. Combining quinoline anti-aging agent with amine anti-aging agent enables high volatility of amine anti-aging agent, tea discoloration and high tan δ on rubber surface, low ozone resistance of quinoline anti-aging agent and gold A rubber composition excellent in the effect of preventing deterioration due to thermal oxidation, the effect of preventing ozone cracks and the effect of preventing the thermal decomposition of rubber components can be obtained while compensating for mold contamination.

  The rubber composition of the present invention has a silane coupling agent 1 having a carbonylthio group (—S—C (═O) —) and not having a mercapto group (—SH) and / or a mercapto group (—SH). The silane coupling agent 2 which has is contained. In the present invention, by using the above-mentioned silane coupling agent 1 and / or silane coupling agent 2 as the silane coupling agent, fuel economy, rubber breaking strength, and wear resistance are remarkably and synergistically improved. be able to. In addition, as a silane coupling agent, it is preferable to use the silane coupling agent 1 and 2 together from the reason that the effect of this invention is acquired more suitably.

［式中、Ｒ¹⁰¹は、−Ｃｌ、−Ｂｒ、−ＯＲ¹⁰⁶、−Ｏ（Ｏ＝）ＣＲ¹⁰⁶、−ＯＮ＝ＣＲ¹⁰⁶Ｒ¹⁰⁷、−ＮＲ¹⁰⁶Ｒ¹⁰⁷および−（ＯＳｉＲ¹⁰⁶Ｒ¹⁰⁷）_h（ＯＳｉＲ¹⁰⁶Ｒ¹⁰⁷Ｒ¹⁰⁸）から選択される一価の基（ここで、Ｒ¹⁰⁶、Ｒ¹⁰⁷およびＲ¹⁰⁸は同一でも異なっていても良く、各々水素原子または炭素数１〜１８の一価の炭化水素基であり、ｈは平均値が１〜４である。）であり、Ｒ¹⁰²はＲ¹⁰¹、水素原子または炭素数１〜１８の一価の炭化水素基、Ｒ¹⁰³は、Ｒ¹⁰¹、Ｒ¹⁰²または水素原子、Ｒ¹⁰⁴は、炭素数１〜１８の二価の炭化水素基、Ｒ¹⁰⁵は炭素数１〜１８の一価の炭化水素基である。］ As the silane coupling agent 1 having a carbonylthio group and not having a mercapto group, a silane coupling agent represented by the following formula (1) can be preferably used.

[Wherein R ¹⁰¹ represents —Cl, —Br, —OR ¹⁰⁶ , —O (O═) CR ¹⁰⁶ , —ON═CR ¹⁰⁶ R ¹⁰⁷ , —NR ¹⁰⁶ R ¹⁰⁷ and — (OSiR ¹⁰⁶ R ¹⁰⁷ ) _h ( A monovalent group selected from OSiR ¹⁰⁶ R ¹⁰⁷ R ¹⁰⁸ , wherein R ¹⁰⁶ , R ¹⁰⁷ and R ¹⁰⁸ may be the same or different and each is a hydrogen atom or a monovalent carbon atom having 1 to 18 carbon atoms. are a hydrogen group, h is the average value of 1~4.), R ¹⁰² is R ^101, a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ¹⁰³ is, R ^101, R ¹⁰² or a hydrogen atom, R ¹⁰⁴ is a divalent hydrocarbon group having 1 to 18 carbon atoms, and R ¹⁰⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms. ]

In the above formula (1), R ¹⁰⁵ , R ¹⁰⁶ , R ¹⁰⁷ and R ¹⁰⁸ are each independently a linear, cyclic or branched alkyl group, alkenyl group, aryl group and aralkyl group having 1 to 18 carbon atoms. A group selected from the group consisting of When R ¹⁰² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, it is a group selected from the group consisting of a linear, cyclic or branched alkyl group, alkenyl group, aryl group and aralkyl group. Preferably there is. R ¹⁰⁹ is preferably a linear, cyclic or branched alkylene group, particularly preferably a linear one. R ¹⁰⁴ is, for example, an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 2 to 18 carbon atoms, a cycloalkylene group having 5 to 18 carbon atoms, a cycloalkyl alkylene group having 6 to 18 carbon atoms, arylene having 6 to 18 carbon atoms And aralkylene groups having 7 to 18 carbon atoms. The alkylene group and alkenylene group may be linear or branched, and the cycloalkylene group, cycloalkylalkylene group, arylene group and aralkylene group are functional groups such as a lower alkyl group on the ring. You may have. R ¹⁰⁴ is preferably an alkylene group having 1 to 6 carbon atoms, particularly a linear alkylene group such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, or a hexamethylene group.

Specific examples of ^{R 102, R 105, R 106} , R 107 and R ¹⁰⁸ are methyl, ethyl, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl Group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclohexenyl group, phenyl group, tolyl Group, xylyl group, naphthyl group, benzyl group, phenethyl group, naphthylmethyl group and the like.

Examples of R ¹⁰⁹ include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, and a hexylene group as the linear alkylene group, and an isopropylene group and an isobutylene as the branched alkylene group. Group, 2-methylpropylene group and the like.

  Specific examples of the silane coupling agent 1 represented by the formula (1) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3 -Lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexa Noylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-o Motor noise Lucio ethyltrimethoxysilane, 2- deca Neu thio ethyltrimethoxysilane, and 2-lauroyl thio ethyl trimethoxysilane. Of these, 3-octanoylthiopropyltriethoxysilane (NXT manufactured by Momentive) is particularly preferable in terms of both workability and low fuel consumption. The silane coupling agent 1 may be used alone or in combination of two or more.

（式中、ｘは１以上の整数、ｙは１以上の整数であり、Ｒ²⁰¹は水素、ハロゲン、直鎖もしくは分岐鎖の炭素数１〜３０のアルキル基、直鎖もしくは分岐鎖の炭素数２〜３０のアルケニル基、直鎖もしくは分岐鎖の炭素数２〜３０のアルキニル基、または該アルキル基の末端の水素が水酸基もしくはカルボキシル基で置換されたものであり、Ｒ²⁰²は、直鎖もしくは分岐鎖の炭素数１〜３０のアルキレン基、直鎖もしくは分岐鎖の炭素数２〜３０のアルケニレン基、または直鎖もしくは分岐鎖の炭素数２〜３０のアルキニレン基であり、あるいはＲ²⁰¹とＲ²⁰²とで環構造を形成してもよい。） As the silane coupling agent 2 having a mercapto group, a silane coupling agent containing a binding unit A represented by the following formula (2-1) and a binding unit B represented by the following formula (2-2) is preferably used. can do.

(Wherein x is an integer of 1 or more, y is an integer of 1 or more, R ²⁰¹ is hydrogen, halogen, a linear or branched alkyl group having 1 to 30 carbon atoms, or a linear or branched carbon number. A alkenyl group having 2 to 30 carbon atoms, a linear or branched alkynyl group having 2 to 30 carbon atoms, or a hydrogen atom substituted at the terminal of the alkyl group with a hydroxyl group or a carboxyl group, and R ²⁰² is a straight chain or A branched chain alkylene group having 1 to 30 carbon atoms, a straight chain or branched chain alkenylene group having 2 to 30 carbon atoms, or a straight chain or branched chain alkenylene group having 2 to 30 carbon atoms, or R ²⁰¹ and R ²⁰² may form a ring structure.)

  The silane coupling agent containing the bond unit A represented by the formula (2-1) and the bond unit B represented by the formula (2-2) is a bis- (3-triethoxysilylpropyl) tetrasulfide or the like. Compared to polysulfide silane, an increase in viscosity during processing is suppressed. This is presumably because the increase in Mooney viscosity is small because the sulfide portion of the bond unit A is a C—S—C bond and is thermally stable compared to tetrasulfide and disulfide.

Moreover, the silane coupling agent containing the bond unit A represented by Formula (2-1) and the bond unit B represented by Formula (2-2) is a mercaptosilane such as 3-mercaptopropyltrimethoxysilane. In comparison, shortening of the scorch time is suppressed. This is because the bonding unit B has a mercaptosilane structure, but the —C ₇ H ₁₅ portion of the bonding unit A covers the —SH group of the bonding unit B, so that it does not easily react with the polymer and scorch is less likely to occur. This is probably because of this.

  From the viewpoint of processability, in the silane coupling agent 2 having the above structure, the content of the bond unit A is preferably 30 mol% or more, more preferably 50 mol% or more, and preferably 99 mol% or less, 90 mol%. The following is more preferable. Further, the content of the bond unit B is preferably 1 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, and preferably 70 mol% or less from the viewpoint of reactivity with silica. 65 mol% or less is more preferable, and 55 mol% or less is still more preferable. Further, the total content of the binding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%.

  The content of the bond units A and B is an amount including the case where the bond units A and B are located at the terminal of the silane coupling agent. The form in which the bonding units A and B are located at the end of the silane coupling agent is not particularly limited, and forms units corresponding to the formulas (2-1) and (2-2) indicating the bonding units A and B. It only has to be.

In the formula (2-1) and the formula (2-2), ^examples of the halogen of R ²⁰¹ include chlorine, bromine, fluorine, and the like.

^Examples of the linear or branched alkyl group having 1 to 30 carbon atoms of ^R201 include methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert -Butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group and the like can be mentioned. The number of carbon atoms of the alkyl group is preferably 1-12.

^Examples of the linear or branched alkenyl group having 2 to 30 carbon atoms represented by R ²⁰¹ include a vinyl group, 1-propenyl group, 2-propenyl group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, 2- Examples thereof include a pentenyl group, 1-hexenyl group, 2-hexenyl group, 1-octenyl group and the like. The alkenyl group preferably has 2 to 12 carbon atoms.

^Examples of the linear or branched alkynyl group having 2 to 30 carbon atoms represented by ^R201 include ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, nonynyl group, decynyl group, and undecynyl group. And dodecynyl group. The alkynyl group preferably has 2 to 12 carbon atoms.

^Examples of the linear or branched alkylene group having 1 to 30 carbon atoms of R ²⁰² include an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, and an undecylene group. , Dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group and the like. The alkylene group preferably has 1 to 12 carbon atoms.

^Examples of the linear or branched alkenylene group having 2 to 30 carbon atoms of R ²⁰² include vinylene group, 1-propenylene group, 2-propenylene group, 1-butenylene group, 2-butenylene group, 1-pentenylene group, 2- Examples include a pentenylene group, a 1-hexenylene group, a 2-hexenylene group, and a 1-octenylene group. The alkenylene group preferably has 2 to 12 carbon atoms.

Examples of the linear or branched C2-C30 alkynylene group of R ²⁰² include ethynylene group, propynylene group, butynylene group, pentynylene group, hexynylene group, heptynylene group, octynylene group, noninylene group, decynylene group, undecynylene group. And dodecynylene group. The alkynylene group preferably has 2 to 12 carbon atoms.

In the silane coupling agent 2 including the bond unit A represented by the formula (2-1) and the bond unit B represented by the formula (2-2), the number of repetitions of the bond unit A (x) and the repetition of the bond unit B The total number of repetitions (x + y) of the number (y) is preferably in the range of 3 to 300. Within this range, since the mercaptosilane of the bond unit B is covered with -C ₇ H ₁₅ of the bond unit A, it is possible to suppress the scorch time from being shortened and to have good reactivity with silica and rubber components. Can be secured.

  Examples of the silane coupling agent 2 including the binding unit A represented by the formula (2-1) and the coupling unit B represented by the formula (2-2) include NXT-Z30 and NXT-Z45 manufactured by Momentive. NXT-Z60 or the like can be used. These may be used alone or in combination of two or more.

  Silane coupling agent 1 and silane coupling agent 2 may be used alone or in combination.

  The total content of the silane coupling agent 1 and the silane coupling agent 2 is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and still more preferably 5 parts by mass or more with respect to 100 parts by mass of silica. By setting the total content of the silane coupling agent 1 and the silane coupling agent 2 to 0.5 parts by mass or more with respect to 100 parts by mass of silica, a sufficient coupling effect is obtained and high silica dispersibility is obtained. Tend to be. Therefore, there is a tendency that good rubber breaking strength can be obtained. Moreover, 15 mass parts or less are preferable with respect to 100 mass parts of silica, as for the total content of the silane coupling agent 1 and the silane coupling agent 2, 12 mass parts or less are more preferable, and 10 mass parts or less are more preferable. By setting the total content of the silane coupling agent 1 and the silane coupling agent 2 to 15 parts by mass or less with respect to 100 parts by mass of silica, an excessive silane coupling agent hardly remains, and the rubber composition obtained There is a tendency for processability and fracture properties to be good.

  The rubber composition in the present invention can be used in combination with silane coupling agents other than those listed above. Conventionally known ones can be used, 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-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropyl base Sulfide series such as zothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, vinyl series such as vinyltriethoxysilane and vinyltrimethoxysilane, 3-aminopropyltriethoxysilane 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, and other amino-based, γ-glycidoxypropyltriethoxysilane , Γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, etc. Chloro, such as nitro, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane Can be mentioned. In addition, said silane coupling agent may be used independently and may use 2 or more types together.

  In addition to the above components, the rubber composition of the present invention includes fillers other than silica; processing aids such as extenders (oils) and lubricants; vulcanization activators such as stearic acid and zinc oxide; organic peroxidation Wax; vulcanizing agent such as sulfur; thiazole vulcanization accelerator, thiuram vulcanization accelerator, sulfenamide vulcanization accelerator, guanidine vulcanization accelerator, etc. It is preferable to contain a filler other than silica.

  As fillers other than silica, they are blended in rubber compositions for the purpose of rubber reinforcement. For example, mica such as calcium carbonate and sericite, aluminum hydroxide, magnesium oxide, magnesium hydroxide, clay White fillers such as talc, alumina, titanium oxide and mica; carbon black and the like. These fillers may be used in combination of two or more, and it is particularly preferable to add carbon black in terms of reinforcement.

  When the rubber composition in the present invention contains a filler other than silica, the content of silica in 100% by mass of the filler is preferably 80% by mass or more, and more preferably 90% by mass or more. By making the content of silica in 100% by mass of the filler 80% by mass or more, the effect of the present invention can be sufficiently obtained. In this case, if carbon black is used as the remaining filler, wet grip performance may be deteriorated. Further, if a filler other than carbon black is used, the wear resistance may be deteriorated.

  When the rubber composition in the present invention includes carbon black, the carbon black may be a furnace black such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF and ECF. Acetylene black (acetylene carbon black); thermal black such as FT and MT (thermal carbon black); channel black such as EPC, MPC and CC (channel carbon black); graphite and the like. These may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is usually 5 to ²⁰⁰ m ² / g, preferably 50 m ² / g or more, and more preferably 80 m ² / g or more. Also, N ₂ SA of the carbon black is preferably 150 meters ² / g or less, more preferably 120 m ² / g. Carbon black has a dibutyl phthalate (DBP) absorption of usually 5 to 300 ml / 100 g, preferably 80 ml / 100 g or more, and more preferably 180 ml / 100 g or less. If the N ₂ SA or DBP absorption amount of carbon black is less than the lower limit of the above range, the reinforcing effect tends to be small and wear resistance tends to decrease. If the upper limit of the above range is exceeded, dispersibility is poor and hysteresis loss increases. There is a tendency for fuel efficiency to decrease.

The N ₂ SA of carbon black is a value measured according to ASTM D4820-93, and the DBP absorption is a value measured according to ASTM D2414-93.

  In the case of containing carbon black, the content with respect to 100 parts by mass of the total rubber component is preferably 1 part by mass or more, and more preferably 3 parts by mass or more. When the carbon black content is 1 part by mass or more, sufficient reinforcing properties tend to be obtained. Further, the content of carbon black with respect to 100 parts by mass of the total rubber component is preferably 60 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 15 parts by mass or less. When the carbon black content is 60 parts by mass or less, better fuel efficiency tends to be obtained.

  As extension oil (oil), aromatic mineral oil (viscosity specific gravity constant (VGC value) 0.900 to 1.049), naphthenic mineral oil (VGC value: 0) 850 to 0.899), paraffinic mineral oil (VGC value: 0.790 to 0.849), and the like. The polycyclic aromatic content of the extending oil is preferably less than 3% by mass, and more preferably less than 1% by mass. The polycyclic aromatic content of the extender oil is measured according to the British Petroleum Institute 346/92 method. Further, the aromatic compound content (CA) of the extending oil is preferably 20% by mass or more. These extending oils may be used alone or in combination of two or more.

  The content with respect to 100 parts by mass of the total rubber component when oil is contained is preferably 10 parts by mass or more, and more preferably 15 parts by mass or more. By setting the oil content to 10 parts by mass or more, there is a tendency that sufficient processability can be ensured and the performance of blending can be derived. Further, the content of oil relative to 100 parts by mass of the total rubber component is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less. By setting the oil content to 50 parts by mass or less, wear resistance tends to be easily secured.

  Examples of the vulcanization accelerator include 2-mercaptobenzothiazole, dibenzothiazyl disulfide, and thiazole vulcanization accelerators such as N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram monosulfide, tetramethylthiuram disulfide Thiuram vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N- Sulfenamide vulcanization accelerators such as oxyethylene-2-benzothiazole sulfenamide, N, N′-diisopropyl-2-benzothiazole sulfenamide; diphenylguanidine, diortolylguanidine, orthotolylbiguanidine, etc. Guani It can be mentioned emission-based vulcanization accelerator. Of these, sulfenamide-based vulcanization accelerators are preferable and N-cyclohexyl-2-benzothiazole sulfenamide is more preferable because the effects of the present invention can be more suitably obtained. It is also preferable to use a guanidine vulcanization accelerator in combination. 0.1-5 mass parts is preferable with respect to 100 mass parts of rubber components, and, as for the usage-amount of a vulcanization accelerator, 0.2-4 mass parts is more preferable.

  Although it does not specifically limit as a vulcanizing agent, Sulfur can be used conveniently. 0.5-5 mass parts is preferable with respect to 100 mass parts of rubber components, and, as for sulfur content, 1-3 mass parts is more preferable. Thereby, the effect of this invention is acquired more suitably.

  Any of waxes, stearic acid, and zinc oxide that are commonly used in the rubber industry can be suitably used.

  The rubber composition in the present invention is a general method except that the amine anti-aging agent is kneaded in a separate step into a kneaded product obtained by kneading the rubber component and all silane coupling agents. Manufactured by. That is, it can be produced by a method of kneading the above components with a Banbury mixer, kneader, open roll or the like and then vulcanizing.

  The rubber composition in the present invention is, for example, Step 1 in which the rubber component of the present invention, silica and all silane coupling agents and other compounding agents are kneaded as necessary, and then the kneaded product obtained in Step 1 1) Kneading a vulcanizing agent and a vulcanization accelerator into the kneaded product 2 obtained in Step 2 and Step 2 of kneading an amine-based anti-aging agent together with silica as necessary. The finishing step 3 for obtaining a rubber composition can be performed. Step 1 includes a step 1a in which a rubber component, a part of silica and a part of a silane coupling agent are kneaded, and the remaining silica and the remaining silane coupling agent in the kneaded product 1a obtained in step 1a. It is also possible to carry out by dividing the process into two steps, ie, the step 1b for kneading. Hereinafter, although the manufacturing method of the rubber composition of this invention is demonstrated by the method of performing the process 1 in two processes, the process 1a and the process 1b, it is not intending to be limited to these manufacturing methods. .

(Step 1a)
The rubber component, silica, silane coupling agent 1 and / or silane coupling agent 2 are kneaded with oil as necessary to obtain a kneaded product 1a. The kneading method of the kneaded product 1a is not particularly limited, and a kneader used in a general rubber industry such as a Banbury mixer and an open roll can be used. A material such as carbon black is preferably added in step 1a.

(Step 1b)
The kneaded product 1a obtained in step 1a, silica, silane coupling agent 1 and / or silane coupling agent 2 are kneaded with oil as necessary to obtain kneaded product 1b. The kneading method of the kneaded product 1b is not particularly limited, and a kneader used in a general rubber industry such as a Banbury mixer and an open roll can be used. Materials such as zinc oxide, stearic acid and wax are copolymers obtained by copolymerizing a silane coupling agent and silica, an aromatic vinyl compound and a conjugated diene compound, for example, S-SBR, rather than being added to step 1a. It is preferable to add in step 1b from the viewpoint of promoting the reaction between SBR and silica.

  The kneading temperature in step 1a and step 1b is preferably 140 ° C. or higher, and more preferably 145 ° C. or higher. By setting the kneading temperature to 140 ° C. or higher, the reaction between the silane coupling agent and silica can be sufficiently promoted, silica can be dispersed well, and fuel economy and wear resistance can be easily improved. In addition, the kneading temperature in step 1a and step 1b is preferably 165 ° C. or lower, and more preferably 160 ° C. or lower. By setting the kneading temperature to 165 ° C. or lower, rubber scorch is prevented and the scorch characteristics and processing characteristics tend to be good. Furthermore, the discharge temperature in step 1a and step 1b is preferably 140 ° C. or higher, more preferably 145 ° C. or higher, from the viewpoint of promoting the reaction of the coupling agent. In addition, the discharge temperature in step 1a and step 1b is preferably 165 ° C. or less, and more preferably 160 ° C. or less, from the viewpoint of workability (sheet fabric) and suppression of viscosity increase.

  The kneading time in the steps 1a and 1b is not particularly limited, but is usually 30 seconds or longer, preferably 1 to 30 minutes, and more preferably 3 to 6 minutes. It is preferable to secure a kneading time of 30 to 150 seconds at a rubber temperature of 140 to 160 ° C.

  Moreover, the process 1a and the process 1b can also be performed at once as the process 1 as mentioned above.

(Process 2)
The kneaded material 1b obtained in the step 1b, the amine-based anti-aging agent, and other various materials as necessary are kneaded together to obtain a kneaded material 2. It is preferable to add an anti-aging agent other than amine-based compounds and a part of silica in the step 2 rather than the step 1a or the step 1b. The kneading method in step 2 is not particularly limited, and a kneader used in a general rubber industry such as a Banbury mixer and an open roll can be used. Although the preferable conditions of the kneading | mixing temperature and discharge | emission temperature in the process 2 are mentioned later, the kneading | mixing temperature and discharge | emission temperature in the process 2 can also be made into the same thing as the process 1, and are not specifically limited.

  The kneading temperature in step 2 is preferably 110 ° C. or higher, and more preferably 115 ° C. or higher. By setting the kneading temperature to 110 ° C. or higher, the added chemicals are sufficiently dispersed and the rubber strength tends to be ensured. Further, the kneading temperature in step 2 is preferably 135 or less, and more preferably 130 ° C. or less. By setting the kneading temperature to 135 ° C. or lower, it is possible to suppress an increase in viscosity and improve productivity. Furthermore, the discharge temperature in step 2 is preferably 110 ° C. or higher, more preferably 120 ° C. or higher, from the viewpoint of ensuring the dispersibility of the chemical. Moreover, the discharge temperature in the step 2 is preferably 140 ° C. or lower, more preferably 135 ° C. or lower, from the viewpoint of securing the dough of the kneaded rubber.

  The kneading time in step 2 is not particularly limited, but is usually 30 seconds or longer, preferably 1 to 30 minutes, more preferably 3 to 6 minutes. It is preferable to secure a kneading time of 30 to 120 seconds at a rubber temperature of 115 to 130 ° C.

(Process 3)
A method of kneading a kneaded product 2 obtained in step 2 with a vulcanizing agent or a vulcanization accelerator by a general method in the rubber industry such as an open roll to obtain an unvulcanized rubber composition and then vulcanizing the kneaded product 2 Thus, the rubber composition of the present invention can be obtained. The kneading in step 3 is not particularly limited, and can be performed using a Banbury mixer or a kneader.

  The kneading temperature in step 3 is preferably 60 ° C. or higher, and more preferably 70 ° C. or higher. By setting the kneading temperature to 60 ° C. or higher, there is a tendency that the chemical is sufficiently dispersed in the rubber to become a homogeneous rubber and the scorch can be suppressed. In addition, the kneading temperature in step 3 is preferably 100 ° C. or lower, and more preferably 90 ° C. or lower. By setting the kneading temperature to 100 ° C. or lower, there is a tendency that rubber scorch is prevented and scorch characteristics and processing characteristics are improved.

  The kneading time in step 3 is not particularly limited, but is usually 30 seconds or longer, preferably 1 to 30 minutes, more preferably 3 to 6 minutes. It is preferable to secure a kneading time of 30 to 120 seconds at a rubber temperature of 60 to 100 ° C.

  The rubber composition in the present invention can be used for each member of a tire (tread, sidewall, carcass, belt, bead, clinch, chafer, etc.), and is particularly preferably used as a tire tread. In the case of a tread having a two-layer structure, the tread is composed of a surface layer (cap tread) and an inner surface layer (base tread) and can be suitably used for both, but it is more preferably used for a cap tread.

  The tire of the present invention can be produced by a usual method using the rubber composition of the present invention. That is, the rubber composition is extruded in accordance with the shape of each tire member such as a tire tread at the unvulcanized stage of the rubber composition of the present invention, and is usually bonded together with other tire members on a tire molding machine. By forming by this method, an unvulcanized tire is formed, and the unvulcanized tire is heated and pressurized in a vulcanizer, whereby the tire of the present invention can be manufactured. A tread having a multilayer structure is manufactured by a method in which a sheet is bonded to a predetermined shape, or a method in which two or more extruders are loaded and two or more layers are formed at the head outlet of the extruder. Can do.

  The tire of the present invention is preferably used as a tire for passenger cars, a tire for trucks and buses, a tire for two-wheeled vehicles, a tire for competitions, and the like, and particularly preferably used as a tire for passenger cars.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited only to an Example.

  The styrene content, weight average molecular weight, number average molecular weight and glass transition temperature of the styrene butadiene copolymer (SBR) (JSR SL563 manufactured by JSR Corporation) and hydrogenated SBR used in the examples were measured as follows. did.

(Measurement of styrene content)
1H-NMR was measured using a JEOL JNM-A 400 NMR apparatus at 25 ° C., and phenyl protons based on 6.5 to 7.2 ppm styrene units and 4.9 to 5.4 ppm butadiene units determined from the spectrum. The styrene content was determined from the ratio of vinyl protons based on.

(Measurement of vinyl bond)
The amount of vinyl bonds in the polymer was determined from the absorption intensity in the vicinity of 910 cm ^−1, which is the absorption peak of the vinyl group, by infrared spectroscopy.

(Measurement of weight average molecular weight (Mw), number average molecular weight (Mn))
The weight average molecular weight (Mw) and number average molecular weight (Mn) of the copolymer were determined by gel permeation chromatography (GPC) (GPC-8000 series, manufactured by Tosoh Corporation), detector: differential refractometer, column: Tosoh Corporation ) Obtained from TSKGEL SUPERMULTIPORE HZ-M, manufactured by TSKGEL, based on standard polystyrene conversion.

(Measurement of glass transition temperature (Tg))
The glass transition temperature (Tg) is measured in accordance with JIS K 7121 using a differential scanning calorimeter (Q200) manufactured by TA Instruments Japan while raising the temperature at a heating rate of 10 ° C./min. Thus, the glass transition start temperature was obtained.

Hereinafter, various chemicals used in Examples and Comparative Examples are shown together.
SBR: JSR SL563 (S-SBR, styrene content: 20%, vinyl bond content: 55.5%, Mw: 6.7 × 10 ⁵ , Mn: 4.4 × 10 ⁵ , Tg: manufactured by JSR Corporation -32 ° C)
BR: BR150B manufactured by Ube Industries, Ltd. (cis 1,4-content 97%)
Silica: ULTRASIL® VN3 (N ₂ SA: 180 m ² / g) manufactured by Evonik Degussa
Silane coupling agent 1: NXT (3-octanoylthio-1-propyltriethoxysilane) manufactured by Momentive
Silane coupling agent 2: NXT-Z45 manufactured by Momentive (copolymer with bonding unit A and bonding unit B (bonding unit A: 55 mol%, bonding unit B: 45 mol%)
Anti-aging agent 1: Antigen 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd.
Anti-aging agent 2: Antigen FR (trimethyldihydroquinoline) manufactured by Sumitomo Chemical Co., Ltd.
Carbon black: Dia Black N339 manufactured by Mitsubishi Chemical Corporation (N ₂ SA: 96 m ² / g, DBP absorption: 124 ml / 100 g)
Oil: X-140 manufactured by Japan Energy Co., Ltd.
Zinc oxide: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Beads stearic acid camellia wax manufactured by NOF Co., Ltd .: Sunnock N manufactured by Ouchi Shinsei Chemical Co., Ltd.
Sulfur: Powder sulfur vulcanization accelerator manufactured by Tsurumi Chemical Co., Ltd. 1: Soxinol CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Sumitomo Chemical Co., Ltd.
Vulcanization accelerator 2: Soxinol D (1,3-diphenylguanidine) manufactured by Sumitomo Chemical Co., Ltd.

Examples 1-6 and Comparative Examples 1-4
<Step 1a>
According to the formulation shown in Step 1a of Table 1, the mixture was kneaded using a 1.7 L Banbury mixer manufactured by Kobe Steel Co., Ltd. under the conditions shown in Table 1, and discharged to obtain a kneaded product 1a.

<Step 1b>
In accordance with the formulation shown in Step 1b of Table 1, the kneaded product 1a and other materials are added, kneaded using a 1.7 L Banbury mixer under the conditions shown in Table 1, discharged, and the kneaded product 1b is discharged. Obtained.

<Process 2>
In accordance with the formulation shown in Step 2 of Table 1, the kneaded product 1b and other materials are added, kneaded using a 1.7 L Banbury mixer under the conditions shown in Table 1, and discharged to obtain a kneaded product 2 It was. In the comparative example, kneading was performed only with the kneaded material 1b.

<Step 3>
According to the formulation shown in Step 3 of Table 1, kneaded product 2, sulfur and a vulcanization accelerator were added and kneaded using an open roll under the conditions shown in Table 1 to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was press vulcanized with a 0.5 mm thick mold at 170 ° C. for 20 minutes to obtain a vulcanized rubber composition.

The details of Conditions 1 to 3 described in Table 1 are as follows.
(Condition 1) Kneading temperature: 150 ° C., kneading time: 5 minutes, discharge temperature: 160 ° C.
(Condition 2) Kneading temperature: 120 ° C., kneading time: 3 minutes, discharge temperature: 130 ° C.
(Condition 3) Kneading temperature: 80 ° C., Kneading time: 5 minutes

  About the obtained unvulcanized rubber composition and vulcanized rubber composition, Mooney viscosity (workability index), low fuel consumption (rolling resistance), and rubber breaking strength were evaluated by the following tests. Each test result is shown in Table 1.

<Mooney viscosity>
Using each unvulcanized rubber composition, according to the Mooney viscosity measuring method according to JIS K6300 “Unvulcanized rubber—physical properties—Part 1: Determination of viscosity and scorch time using Mooney viscometer”, 130 Mooney viscosity (ML _{1 + 4} ) was measured under the temperature condition of ° C. The Mooney viscosity of Comparative Example 1 was taken as 100, and the Mooney viscosity of each formulation was displayed as an index (workability index). The larger the index, the lower the Mooney viscosity and the better the processability. Note that 104 or more is a performance target value.

<Rolling resistance>
A strip-shaped test piece having a width of 1 mm or 2 mm and a length of 40 mm was punched out of the sheet-like vulcanized rubber composition and subjected to the test. Using a spectrometer manufactured by Ueshima Seisakusho, loss tangent (tan δ) of the vulcanized rubber composition was measured at a dynamic strain amplitude of 1%, a frequency of 10 Hz, and a temperature of 50 ° C. The reciprocal value of tan δ was displayed as an index with Comparative Example 1 being 100 (low fuel consumption index). The larger the value, the lower the rolling resistance and the better the fuel efficiency of the tire.

<Rubber breaking strength>
In accordance with JIS K 6251 “How to Obtain Tensile Properties of Vulcanized Rubber and Thermoplastic Rubber”, a tensile test was performed in an atmosphere at 25 ° C. using a No. 3 dumbbell-shaped test piece made of the above vulcanized rubber composition, and fracture occurred. Elongation was measured. The measurement results are shown as an index (rubber strength index) with Comparative Example 1 as 100. The larger the index, the greater the rubber breaking strength.

  From the results shown in Table 1, good low fuel consumption can be maintained and workability can be maintained by kneading an amine-based anti-aging agent in a separate process to a kneaded product containing a rubber component, silica and all silane coupling agents. It can also be seen that a rubber composition excellent in rubber strength can be obtained.

Claims (8)

60 to 200 parts by mass of silica and 1.5 to 5.0 of an amine-based anti-aging agent with respect to 100 parts by mass of a rubber component containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound. The group which consists of silane coupling agent 1 which has a carbonylthio group (-S-C (= O)-) and does not have a mercapto group (-SH), and silane coupling agent 2 which has a mercapto group containing a mass part A rubber composition containing at least one silane coupling agent selected from the above, wherein the amine anti-aging agent is mixed in a separate kneading step after kneading the rubber component and all the silane coupling agents. A rubber composition obtained by kneading. The rubber composition according to claim 1, wherein the discharge temperature of the kneading step in which the amine-based antioxidant is mixed is 110 to 140 ° C. The rubber composition according to claim 1 or 2, wherein the total content of the silane coupling agent 1 and the silane coupling agent 2 is 1 to 10 parts by mass with respect to 100 parts by mass of silica. The rubber composition according to any one of claims 1 to 3, wherein the rubber composition contains a silane coupling agent 1 and the silane coupling agent 1 is a silane coupling agent represented by the following formula (1).

[Wherein R ¹⁰¹ represents —Cl, —Br, —OR ¹⁰⁶ , —O (O═) CR ¹⁰⁶ , —ON═CR ¹⁰⁶ R ¹⁰⁷ , —NR ¹⁰⁶ R ¹⁰⁷ and — (OSiR ¹⁰⁶ R ¹⁰⁷ ) _h ( A monovalent group selected from OSiR ¹⁰⁶ R ¹⁰⁷ R ¹⁰⁸ , wherein R ¹⁰⁶ , R ¹⁰⁷ and R ¹⁰⁸ may be the same or different and each is a hydrogen atom or a monovalent carbon atom having 1 to 18 carbon atoms. are a hydrogen group, h is the average value of 1~4.), R ¹⁰² is R ^101, a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ¹⁰³ is, R ^101, R ¹⁰² or a hydrogen atom, R ¹⁰⁴ is a divalent hydrocarbon group having 1 to 18 carbon atoms, and R ¹⁰⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms. ] Silane containing the silane coupling agent 2 and including the bonding unit A represented by the following formula (2-1) and the bonding unit B represented by the following formula (2-2). It is a coupling agent, The rubber composition of any one of Claims 1-4.

(Wherein x is an integer of 1 or more, y is an integer of 1 or more, R ²⁰¹ is hydrogen, halogen, a linear or branched alkyl group having 1 to 30 carbon atoms, or a linear or branched carbon number. A alkenyl group having 2 to 30 carbon atoms, a linear or branched alkynyl group having 2 to 30 carbon atoms, or a hydrogen atom substituted at the terminal of the alkyl group with a hydroxyl group or a carboxyl group, and R ²⁰² is a straight chain or A branched chain alkylene group having 1 to 30 carbon atoms, a straight chain or branched chain alkenylene group having 2 to 30 carbon atoms, or a straight chain or branched chain alkenylene group having 2 to 30 carbon atoms, or R ²⁰¹ and R ²⁰² may form a ring structure.) A pneumatic tire provided with the tire member comprised with the rubber composition of any one of Claims 1-5. The pneumatic tire according to claim 6, wherein the tire member is a tread. 60 to 200 parts by mass of silica and 1.5 to 5.0 of an amine-based anti-aging agent with respect to 100 parts by mass of a rubber component containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound. The group which consists of silane coupling agent 1 which has a carbonylthio group (-S-C (= O)-) and does not have a mercapto group (-SH), and silane coupling agent 2 which has a mercapto group containing a mass part A method for producing a rubber composition containing at least one silane coupling agent selected from the above, wherein the rubber component and all the silane coupling agents are kneaded, and after step 1, amine-based aging prevention A method for producing a rubber composition, comprising the step 2 of kneading the agent.