JP5725365B2 - Rubber composition, cross-linked product thereof, and production method thereof - Google Patents

Description

  The present invention relates to a rubber composition containing an unsaturated group-containing rubber, a silane coupling agent-treated filler, a silica-based filler, and a silane coupling agent, and a method for producing the same, and a crosslinked product obtained by crosslinking the rubber composition. About.

  From the viewpoint of environmental protection, there is a strong demand for fuel saving and resource saving for tires. Fuel saving has achieved certain results by using silica. However, when silica is added, the viscosity of the rubber composition increases. By adding a silane coupling agent, the increase in viscosity is alleviated. ing. Silane coupling agents are known to reduce the interaction between silicas by reacting with silanols on the silica surface, thereby reducing the loss tangent and dynamic modulus of rubber.

  In order to save resources, efforts are being made to extend the life of tires by improving wear resistance. In the case of silica, it is necessary to chemically combine silica and a polymer in order to improve wear resistance, and generally bis (triethoxysilylpropyl) polysulfide is used.

  However, the effects of the prior art are insufficient for the recent environmental deterioration, and further fuel saving and resource saving are demanded.

  In order to solve the above problems, a coupling agent that has high reactivity between silica and a silane coupling agent and good workability has been proposed, but it is practically problematic from the viewpoint of economy and the like. There are many (refer patent document 1).

  In addition, proposals have been made to disperse rubber latex and carbon black in water and use a solidified rubber component, but in order to evaporate the water and dry it, a lot of heat energy is required, which is economical and There is a problem from the viewpoint of environment (see Patent Document 2).

  Similarly, a treated silica is known in which silica is reacted with a sulfide-based silane coupling agent in a hot atmosphere. However, the silica-containing composition has a problem in moldability because of an increase in viscosity of the composition. (See Patent Document 3).

Published patent publication, 2008-110997 Published Patent Publication, 2006-225598 Published Patent Publication, 2006-249387

  In view of the above points, the present invention provides a rubber composition having excellent scorch properties and low viscosity, reducing loss tangent corresponding to rolling resistance of the crosslinked product, and reducing loss tangent of low temperature portion corresponding to wet grip. An object of the present invention is to provide a rubber composition having a low content and a production method thereof.

  As a result of intensive studies, the present inventors have found that a rubber composition containing a surface-treated silica-based filler surface-treated with a silane coupling agent on a unsaturated group-containing rubber, a silica-based filler, and a silane coupling agent has a low viscosity. The present invention provides a rubber composition, and the cross-linked product thereof has reduced loss tangent corresponding to rolling resistance and found that a rubber composition and a cross-linked product can be obtained in which the loss tangent of a low temperature portion corresponding to a wet grip is small. It reached.

That is, the present invention relates to (a) 100 parts by weight of unsaturated group-containing rubber,
(B) 5 to 50 parts by weight of a surface-treated silica-based filler surface-treated with a silane coupling agent A) that is a surface-treating agent of 10 to 20 parts by weight with respect to 100 parts by weight of a silica-based filler;
(C) 10 to 200 parts by weight of a silica filler having a BET specific surface area of 20 to 300 m ² / g,
(D) A composition containing 1 to 30 parts by weight of silane coupling agent B), a vulcanized product obtained by vulcanizing the composition, and a method for producing them.

  The rubber composition obtained by the present invention is excellent in processability because of its low viscosity, and the crosslinked product obtained by crosslinking the composition has a loss tangent corresponding to rolling resistance of 60 ° C. tan δ, There is little decrease in tan δ at 0 ° C., which is the loss tangent of the low temperature portion corresponding to the wet grip. In general, as the tan δ at 60 ° C. decreases, that is, the rolling resistance becomes more favorable, the decrease in tan δ at 0 ° C. also increases, that is, the wet grip tends to deteriorate. The object is suitable for rubber parts such as tire treads and vibration-proof rubbers.

Hereinafter, the rubber composition of the present invention will be described in detail.
The rubber composition of the present invention is surface-treated with at least (a) an unsaturated group-containing rubber and (b) a silane coupling agent A) that is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of a silica-based filler. And (c) a silica-based filler having a BET specific surface area of 20 to 300 m ² / g, and (d) a silane coupling agent B).

  (A) Unsaturated group-containing rubber used in the present invention is natural rubber, isoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene-terpolymer, butyl rubber, epoxidized. Of these, natural rubber, natural rubber, isoprene rubber, polybutadiene rubber, and styrene-butadiene copolymer rubber are preferable. These unsaturated group-containing rubbers may be one kind or a blend of two or more kinds.

In the surface-treated silica-based filler surface-treated with the silane coupling agent A) that is 10 to 20 parts by weight of the surface-treating agent with respect to 100 parts by weight of the silica-based filler (b) of the present invention, the silane coupling agent A) Examples of the silica filler to be treated with clay include clay, mica, dry silica, and wet silica, and a silica filler having a BET specific surface area of 20 to 300 m ² / g is preferable. Silica filler treated with a silane coupling agent A) is, BET specific surface area is more preferably a wet silica 20~250m ² / g, BET specific surface area is particularly preferable wet silica of 50 to 250 m ² / g. Silica-based fillers having a specific surface area in these ranges are preferred because they are suitable for kneading stress at the time of kneading the rubber composition and can provide a reaction promoting effect between the silica-based filler and the silane coupling agent.

  As a silane coupling agent A) which is a surface treatment agent for performing surface treatment on a silica filler, a vinyl silane silane coupling agent, an amino silane silane coupling agent, an epoxy silane silane coupling agent, a methacryloxy silane silane cup Examples include a ring agent, a (poly) sulfide silane coupling agent, a mercaptosilane silane coupling agent, and a protected mercaptosilane silane coupling agent. A (poly) sulfide-based silane coupling agent, a mercaptosilane-based silane coupling agent, and a protected mercaptosilane-based silane coupling agent are preferable, and two or more of these silane coupling agents may be used in combination.

  As the vinyl silane coupling agent of the present invention, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, allyltrichlorosilane, allyltrimethoxysilane, allyltriethoxysilane, diethoxymethylvinylsilane, Examples include trichlorovinylsilane and triethoxyvinylsilane.

  Examples of the amino silane coupling agent of the present invention include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2- Examples include aminoethyl) -3-aminopropylmethyldimethoxysilane, 3- (N-phenyl) aminopropyltrimethoxysilane, and the like.

  Examples of the epoxy silane coupling agent of the present invention include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane. The

That is, the present invention relates to (a) 100 parts by weight of unsaturated group-containing rubber,
(B) 5 to 50 parts by weight of a surface-treated silica-based filler surface-treated with a silane coupling agent A) that is a surface-treating agent of 10 to 20 parts by weight with respect to 100 parts by weight of a silica-based filler;
(C) 10 to 200 parts by weight of a silica filler having a BET specific surface area of 20 to 300 m ² / g,
(D) A composition containing 1 to 30 parts by weight of the silane coupling agent B), a crosslinked product obtained by crosslinking the composition, and a method for producing them.

（式中、Ｒ^１は炭素数１〜４の一価のアルコキシ基または炭素数３〜４０のポリアルキレングリコールモノアルキルエーテル基、Ｒ^２は炭素数１〜１８の一価の炭化水素基、Ｒ^３は炭素数１〜９の二価の炭化水素基、ｘは２〜６、_Ｙは０、１、または２の整数である。）
Ｒ^１は炭素数１〜３の一価のアルコキシ基または炭素数４〜２４のポリアルキレングリコールモノアルキルエーテル基であることが好ましく、炭素数１〜２の一価のアルコキシ基または炭素数４〜１８のポリアルキレングリコールモノアルキルエーテル基であることがより好ましい。
Ｒ^２は炭素数１〜８の一価の炭化水素基であることが好ましく、炭素数１〜４の一価の炭化水素基であることがより好ましい。
Ｒ^３は炭素数１〜６の二価の炭化水素基であることが好ましく、炭素数２〜４の二価の炭化水素基であることがより好ましい。
具体的には、ビス（３−トリエトキシシリルプロピル）ジスルフィド（略称ＴＥＳＰＤ）、ビス（３−トリエトキシシリルプロピル）テトラスルフィド（略称ＴＥＳＰＴ）などのビス（３−トリエトキシシリルプロピル）ポリスルフィド（略称ＴＥＳＰＰ）が例示される。 Examples of the (poly) sulfide-based silane coupling agent of the present invention include (poly) sulfide-based silane coupling agents represented by the following general formula (I).

Wherein R ¹ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ³ is a divalent hydrocarbon group having 1 to 9 carbon atoms, x is 2 to 6, and _Y is an integer of 0, 1, or 2.
R ¹ is preferably a monovalent alkoxy group having 1 to 3 carbon atoms or a polyalkylene glycol monoalkyl ether group having 4 to 24 carbon atoms, and a monovalent alkoxy group having 1 to 2 carbon atoms or 4 to 4 carbon atoms. More preferred are 18 polyalkylene glycol monoalkyl ether groups.
R ² is preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms.
R ³ is preferably a divalent hydrocarbon group having 1 to 6 carbon atoms, and more preferably a divalent hydrocarbon group having 2 to 4 carbon atoms.
Specifically, bis (3-triethoxysilylpropyl) disulfide (abbreviated as TESPD), bis (3-triethoxysilylpropyl) polysulfide (abbreviated as TESPP) such as bis (3-triethoxysilylpropyl) tetrasulfide (abbreviated as TESPT), and the like. ) Is exemplified.

（式中、Ｒ^４は炭素数１〜４の一価のアルコキシ基または炭素数３〜４０のポリアルキレングリコールモノアルキルエーテル基、Ｒ^５は炭素数１〜１８の一価の炭化水素基、Ｒ^６は炭素数１〜９の二価の炭化水素基、_Ｙは０、１、または２の整数である。）
Ｒ^４は炭素数１〜３の一価のアルコキシ基または炭素数４〜２４のポリアルキレングリコールモノアルキルエーテル基であることが好ましく、炭素数１〜２の一価のアルコキシ基または炭素数４〜１８のポリアルキレングリコールモノアルキルエーテル基であることがより好ましい。
Ｒ^５は炭素数１〜８の一価の炭化水素基であることが好ましく、炭素数１〜４の一価の炭化水素基であることがより好ましい。
Ｒ^６は炭素数１〜６の二価の炭化水素基であることが好ましく、炭素数２〜４の二価の炭化水素基であることがより好ましい。
具体的には３−メルカプトプロピルトリメトキシシラン、３−メルカプトプロピルトリエトキシシラン等が例示される。 Examples of the mercapto silane coupling agent of the present invention include mercapto silane coupling agents represented by the following general formula (II).

Wherein R ⁴ is a monovalent alkoxy group having 1 to ⁴ carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁶ is a divalent hydrocarbon group having 1 to 9 carbon atoms, and _Y is an integer of 0, 1, or 2.)
R ⁴ is preferably a monovalent alkoxy group having 1 to 3 carbon atoms or a polyalkylene glycol monoalkyl ether group having 4 to 24 carbon atoms, and a monovalent alkoxy group having 1 to 2 carbon atoms or 4 to 4 carbon atoms. More preferred are 18 polyalkylene glycol monoalkyl ether groups.
R ⁵ is preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms.
R ⁶ is preferably a C 1-6 divalent hydrocarbon group, and more preferably a C 2-4 divalent hydrocarbon group.
Specific examples include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

（式中、Ｒ^７は炭素数１〜４の一価のアルコキシ基または炭素数３〜４０のポリアルキレングリコールモノアルキルエーテル基、Ｒ^８は炭素数１〜１８の一価の炭化水素基、Ｒ^９は炭素数１〜９の二価の炭化水素基、Ｒ^１０は炭素数１〜１８の一価の炭化水素基、_Ｙは０、１、または２の整数である。）
Ｒ^７は炭素数１〜３の一価のアルコキシ基または炭素数４〜２４のポリアルキレングリコールモノアルキルエーテル基であることが好ましく、炭素数１〜２の一価のアルコキシ基または炭素数４〜１８のポリアルキレングリコールモノアルキルエーテル基であることがより好ましい。
Ｒ^８は炭素数１〜８の一価の炭化水素基であることが好ましく、炭素数１〜４の一価の炭化水素基であることがより好ましい。
Ｒ^９は炭素数１〜６の二価の炭化水素基であることが好ましく、炭素数２〜４の二価の炭化水素基であることがより好ましい。
Ｒ^１０は炭素数１〜１８の一価の炭化水素基であることが好ましく、炭素数８〜１８の一価の炭化水素基であることがより好ましい。
具体的には３−オクタノイルチオ−１−プロピルトリエトキシシラン、３−プロピオニルチオプロピルトリメトキシシランなどが好ましいものとして挙げられる。 Examples of the protected mercapto silane coupling agent of the present invention include a protected mercapto silane coupling agent represented by the following general formula (III).

(In the formula, R ⁷ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁸ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁹ is a divalent hydrocarbon group having 1 to 9 carbon atoms, R ¹⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and _Y is an integer of 0, 1, or 2.
R ⁷ is preferably a monovalent alkoxy group having 1 to 3 carbon atoms or a polyalkylene glycol monoalkyl ether group having 4 to 24 carbon atoms, and a monovalent alkoxy group having 1 to 2 carbon atoms or 4 to 4 carbon atoms. More preferred are 18 polyalkylene glycol monoalkyl ether groups.
R ⁸ is preferably a monovalent hydrocarbon group having 1 to ⁸ carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms.
R ⁹ is preferably a divalent hydrocarbon group having 1 to 6 carbon atoms, and more preferably a divalent hydrocarbon group having 2 to 4 carbon atoms.
R ¹⁰ is preferably a monovalent hydrocarbon group having 1 to 18 carbon atoms, and more preferably a monovalent hydrocarbon group having 8 to 18 carbon atoms.
Specifically, 3-octanoylthio-1-propyltriethoxysilane, 3-propionylthiopropyltrimethoxysilane and the like are preferable.

  The surface-treated silica-based filler surface-treated in the present invention includes sulfur-containing silane cups such as (poly) sulfide-based silane-based silane coupling agents, mercaptosilane-based silane coupling agents, and protected mercaptosilane-based silane coupling agents. It is preferable that it is a silica type filler surface-treated only with a ring agent.

例えば、１００ｇのシリカに対し１５．０ｇのシランカップリング剤の割合で処理した場合、溶剤にて抽出された残量が１．０ｇであったとすると、表面処理されたシリカ１００重量部あたりの添加された表面処理剤の総量は１５．０／（１５．０＋１００）となる。よって残渣率は１．０／｛１５．０／（１５．０＋１００）×１００｝≒０．０７７となる。 100 parts by weight of the surface-treated silica-based filler surface-treated with 10 to 20 parts by weight of the silane coupling agent A) is extracted with a solvent with respect to 100 parts by weight of the silica-based filler of the present invention. When processed, the value of the residue ratio determined by the formula (1) is preferably 0.4 or less, more preferably 0.3 or less, and particularly preferably 0.2 or less. However, the surface treatment agent includes everything used for the surface treatment of the silica filler, including the silane coupling agent.

For example, when the amount of the silane coupling agent is 15.0 g with respect to 100 g of silica and the remaining amount extracted with a solvent is 1.0 g, the addition per 100 parts by weight of the surface-treated silica The total amount of the surface treatment agent thus obtained is 15.0 / (15.0 + 100). Therefore, the residue rate is 1.0 / {15.0 / (15.0 + 100) × 100} ≈0.077.

  The solvent used for extracting the surface-treated silica filler is preferably a solvent that can extract the surface treatment agent and does not easily react with the surface treatment agent and further does not promote the reaction between the surface treatment agents. . Preferred solvents include ketones and aliphatic hydrocarbons. Specifically, acetone, methyl ethyl ketone (2-butanone), hexane, cyclohexane and the like can be exemplified, and it is more preferable that dehydration treatment is performed with molecular sieves or the like.

  (B) A method for producing a surface-treated silica-based filler surface-treated with a silane coupling agent A) that is 10 to 20 parts by weight of the surface-treating agent with respect to 100 parts by weight of the silica-based filler is silica. It is obtained by mixing and reacting 10 to 20 parts by weight of the silane coupling agent with respect to 100 parts by weight of the system filler, preferably 10 to 18 parts by weight, and more preferably 12 to 18 parts by weight. preferable. If it is this range, it is preferable at the point which reaction of a silica type filler and a silane coupling agent advances sufficiently.

  It is preferable to add a hydroxy acid when the silica filler is surface-treated with the silane coupling agent A) which is a surface treatment agent.

  Specific examples of hydroxy acids include saturated aliphatic hydroxy acids such as lactic acid, citric acid, isocitric acid, malic acid, tartaric acid, ricinoleic acid, hydroxystearic acid, etc., salicylic acid, mandelic acid, creosote Examples thereof include aromatic hydroxy acids such as acid and coumaric acid, but are not limited thereto. The hydroxy acid used in the present invention is preferably lactic acid and / or salicylic acid.

  The compounding quantity of the said hydroxy acid is 0.1-10 weight part with respect to 100 weight part of silica-type fillers, and it is preferable that it is 0.1-5 weight part. If it is the range of 0.1-10 weight part, since the effect which accelerates | stimulates reaction with a silica type filler and silane coupling agent A) is acquired, it is preferable.

  In the rubber composition of the present invention, (a) 100 parts by weight of the unsaturated group-containing rubber, and (b) 10-20 parts by weight of the surface treatment agent for 100 parts by weight of the silica-based filler. 5 to 50 parts by weight of the surface-treated silica filler surface-treated with the agent A) is preferably contained, more preferably 10 to 50 parts by weight, and particularly preferably 15 to 50 parts by weight. preferable. If it is this range, the viscosity of a rubber composition falls and it is preferable at the point which reaction of a silica type filler and a silane coupling agent advances sufficiently.

Examples of the silica-based filler (c) having a BET specific surface area of 20 to 300 m ² / g used in the present invention include clay, mica, dry silica, and wet silica having a BET specific surface area of 20 to 300 m ² / g. BET specific surface area of preferably wet silica 20~250m ² / g, BET specific surface area is more preferable wet silica of 50 to 250 m ² / g. Silica-based fillers having a specific surface area in these ranges are preferable in terms of the reactivity between the silica-based filler and the silane coupling agent and the reinforcing property of the crosslinked rubber. As the silica-based filler used in the present invention, Tossil silica Nipsil VN-3, AQ, ER, E743, Oriental Silica Toxil 255, UR, GU, 233, Degussa Ultrasil VN3, Commercially available silica such as VN2 is used. Further, from the viewpoint of workability, granular to massive silica fillers such as granules and micropearls are particularly preferable. Examples thereof include Nipsil AQ and ER-R manufactured by Tosoh Silica, Zeosyl 115GR and 1165MP manufactured by Rhodia. .

In the rubber composition of the present invention, (a) 100 parts by weight of the unsaturated group-containing rubber contains (c) 10 to 200 parts by weight of a silica-based filler having a BET specific surface area of 20 to 300 m ² / g. Preferably, it contains 10 to 120 parts by weight, more preferably 15 to 100 parts by weight. If it is this range, if it is this range, the viscosity raise of a rubber composition will be suppressed and the reinforcement | strengthening property of a crosslinked material is also favorable, and it is preferable.

  The (d) silane coupling agent B) used in the present invention is not particularly limited as in the case of the silane coupling agent A) described above, but a vinylsilane silane coupling agent and an aminosilane silane coupling. Agents, epoxy silane silane coupling agents, methacryloxy silane silane coupling agents, (poly) sulfide silane coupling agents, mercapto silane silane coupling agents, and protected mercapto silane silane coupling agents. . A (poly) sulfide-based silane coupling agent, a mercaptosilane-based silane coupling agent, and a protected mercaptosilane-based silane coupling agent are preferable, and two or more of these silane coupling agents may be used in combination.

  As the vinyl silane coupling agent of the present invention, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, allyltrichlorosilane, allyltrimethoxysilane, allyltriethoxysilane, diethoxymethylvinylsilane, Examples include trichlorovinylsilane and triethoxyvinylsilane.

  Examples of the amino silane coupling agent of the present invention include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2- Examples include aminoethyl) -3-aminopropylmethyldimethoxysilane, 3- (N-phenyl) aminopropyltrimethoxysilane, and the like.

  Examples of the epoxy silane coupling agent of the present invention include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane. The

  Examples of the methacryloxy silane coupling agent of the present invention include 3-methacryloxypropyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane.

（式中、Ｒ^１は炭素数１〜４の一価のアルコキシ基または炭素数３〜４０のポリアルキレングリコールモノアルキルエーテル基、Ｒ^２は炭素数１〜１８の一価の炭化水素基、Ｒ^３は炭素数１〜９の二価の炭化水素基、ｘは２〜６、_Ｙは０、１、または２の整数である。）
Ｒ^１は炭素数１〜３の一価のアルコキシ基または炭素数４〜２４のポリアルキレングリコールモノアルキルエーテル基であることが好ましく、炭素数１〜２の一価のアルコキシ基または炭素数４〜１８のポリアルキレングリコールモノアルキルエーテル基であることがより好ましい。
Ｒ^２は炭素数１〜８の一価の炭化水素基であることが好ましく、炭素数１〜４の一価の炭化水素基であることがより好ましい。
Ｒ^３は炭素数１〜６の二価の炭化水素基であることが好ましく、炭素数２〜４の二価の炭化水素基であることがより好ましい。
具体的には、ビス（３−トリエトキシシリルプロピル）ジスルフィド（略称ＴＥＳＰＤ）、ビス（３−トリエトキシシリルプロピル）テトラスルフィド（略称ＴＥＳＰＴ）などのビス（３−トリエトキシシリルプロピル）ポリスルフィド（略称ＴＥＳＰＰ）が例示される。 Examples of the (poly) sulfide-based silane coupling agent of the present invention include (poly) sulfide-based silane coupling agents represented by the following general formula (I).

Wherein R ¹ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ³ is a divalent hydrocarbon group having 1 to 9 carbon atoms, x is 2 to 6, and _Y is an integer of 0, 1, or 2.
R ¹ is preferably a monovalent alkoxy group having 1 to 3 carbon atoms or a polyalkylene glycol monoalkyl ether group having 4 to 24 carbon atoms, and a monovalent alkoxy group having 1 to 2 carbon atoms or 4 to 4 carbon atoms. More preferred are 18 polyalkylene glycol monoalkyl ether groups.
R ² is preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms.
R ³ is preferably a divalent hydrocarbon group having 1 to 6 carbon atoms, and more preferably a divalent hydrocarbon group having 2 to 4 carbon atoms.
Specifically, bis (3-triethoxysilylpropyl) disulfide (abbreviated as TESPD), bis (3-triethoxysilylpropyl) polysulfide (abbreviated as TESPP) such as bis (3-triethoxysilylpropyl) tetrasulfide (abbreviated as TESPT), and the like. ) Is exemplified.

（式中、Ｒ^４は炭素数１〜４の一価のアルコキシ基または炭素数３〜４０のポリアルキレングリコールモノアルキルエーテル基、Ｒ^５は炭素数１〜１８の一価の炭化水素基、Ｒ^６は炭素数１〜９の二価の炭化水素基、_Ｙは０、１、または２の整数である。）
Ｒ^４は炭素数１〜３の一価のアルコキシ基または炭素数４〜２４のポリアルキレングリコールモノアルキルエーテル基であることが好ましく、炭素数１〜２の一価のアルコキシ基または炭素数４〜１８のポリアルキレングリコールモノアルキルエーテル基であることがより好ましい。
Ｒ^５は炭素数１〜８の一価の炭化水素基であることが好ましく、炭素数１〜４の一価の炭化水素基であることがより好ましい。
Ｒ^６は炭素数１〜６の二価の炭化水素基であることが好ましく、炭素数２〜４の二価の炭化水素基であることがより好ましい。
具体的には３−メルカプトプロピルトリメトキシシラン、３−メルカプトプロピルトリエトキシシラン等が例示される。 Examples of the mercapto silane coupling agent of the present invention include mercapto silane coupling agents represented by the following general formula (II).

Wherein R ⁴ is a monovalent alkoxy group having 1 to ⁴ carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁶ is a divalent hydrocarbon group having 1 to 9 carbon atoms, and _Y is an integer of 0, 1, or 2.)
R ⁴ is preferably a monovalent alkoxy group having 1 to 3 carbon atoms or a polyalkylene glycol monoalkyl ether group having 4 to 24 carbon atoms, and a monovalent alkoxy group having 1 to 2 carbon atoms or 4 to 4 carbon atoms. More preferred are 18 polyalkylene glycol monoalkyl ether groups.
R ⁵ is preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms.
R ⁶ is preferably a C 1-6 divalent hydrocarbon group, and more preferably a C 2-4 divalent hydrocarbon group.
Specific examples include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

（式中、Ｒ^７は炭素数１〜４の一価のアルコキシ基または炭素数３〜４０のポリアルキレングリコールモノアルキルエーテル基、Ｒ^８は炭素数１〜１８の一価の炭化水素基、Ｒ^９は炭素数１〜９の二価の炭化水素基、Ｒ^１０は炭素数１〜１８の一価の炭化水素基、_Ｙは０、１、または２の整数である。）
Ｒ^７は炭素数１〜３の一価のアルコキシ基または炭素数４〜２４のポリアルキレングリコールモノアルキルエーテル基であることが好ましく、炭素数１〜２の一価のアルコキシ基または炭素数４〜１８のポリアルキレングリコールモノアルキルエーテル基であることがより好ましい。
Ｒ^８は炭素数１〜８の一価の炭化水素基であることが好ましく、炭素数１〜４の一価の炭化水素基であることがより好ましい。
Ｒ^９は炭素数１〜６の二価の炭化水素基であることが好ましく、炭素数２〜４の二価の炭化水素基であることがより好ましい。
Ｒ^１０は炭素数１〜１８の一価の炭化水素基であることが好ましく、炭素数８〜１８の一価の炭化水素基であることがより好ましい。
具体的には３−オクタノイルチオ−１−プロピルトリエトキシシラン、３−プロピオニルチオプロピルトリメトキシシランなどが好ましいものとして挙げられる。 Examples of the protected mercapto silane coupling agent of the present invention include a protected mercapto silane coupling agent represented by the following general formula (III).

(In the formula, R ⁷ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁸ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁹ is a divalent hydrocarbon group having 1 to 9 carbon atoms, R ¹⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and _Y is an integer of 0, 1, or 2.
R ⁷ is preferably a monovalent alkoxy group having 1 to 3 carbon atoms or a polyalkylene glycol monoalkyl ether group having 4 to 24 carbon atoms, and a monovalent alkoxy group having 1 to 2 carbon atoms or 4 to 4 carbon atoms. More preferred are 18 polyalkylene glycol monoalkyl ether groups.
R ⁸ is preferably a monovalent hydrocarbon group having 1 to ⁸ carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms.
R ⁹ is preferably a divalent hydrocarbon group having 1 to 6 carbon atoms, and more preferably a divalent hydrocarbon group having 2 to 4 carbon atoms.
R ¹⁰ is preferably a monovalent hydrocarbon group having 1 to 18 carbon atoms, and more preferably a monovalent hydrocarbon group having 8 to 18 carbon atoms.
Specifically, 3-octanoylthio-1-propyltriethoxysilane, 3-propionylthiopropyltrimethoxysilane and the like are preferable.

  Specific examples of the silane coupling agent B) used in the present invention include Daiso's Cabras 2A, Cabras 2B, Cabras 4, Sieg-75, Si-69, Si-363 from Degussa, Momentive A-1289, NXT, NXT-LowV, A-189, KBE-846 manufactured by Shin-Etsu Chemical Co., Ltd., and the like are exemplified, but not limited thereto.

  In the rubber composition of this invention, it is preferable to contain 1-30 weight part of (d) silane coupling agent B) with respect to 100 weight part of (a) unsaturated group containing rubber | gum, 1-20 weight part It is more preferable to contain a part, and it is especially preferable to contain 1-10 weight part. If it is this range, if it is this range, the viscosity of a rubber composition will fall and reduction of the loss tangent equivalent to the rolling resistance of a crosslinked material will fully be obtained.

  The rubber composition of the present invention includes a vulcanization accelerator, an anti-aging agent, a filler, a reinforcing agent, a processing aid, a plasticizer, and a softening agent used in this field in order to improve processability during kneading. May be used alone or in combination of two or more. Although there is no particular limitation, fatty acid, fatty acid amide, fatty acid ester, metal salt of fatty acid, paraffin wax, phthalic acid derivative, stearic acid derivative, various process oils such as paraffinic / naphthenic / aromatics, polyethylene glycols, etc. .

For the production of the rubber composition of the present invention, a kneader generally used in the rubber industry is used. Specific examples include an open roll, a pressure kneader, a Banbury mixer, and an intermix. The kneading temperature is preferably 60 to 200 ° C, more preferably 100 to 180 ° C. Within this range, the reaction between the silica filler having a BET specific surface area of 20 to 300 m ² / g and the silane coupling agent B) sufficiently proceeds, and the gelation of the rubber does not proceed, so the workability is also good. is there. The kneading time is not particularly limited, but is, for example, 1 minute to 1 hour.

The method for producing the rubber composition of the present invention includes (a) an unsaturated group-containing rubber component and (b) a silica-based filler 100 before kneading (a) an unsaturated group-containing rubber component and (c) a silica-based filler. The surface-treated silica-based filler surface-treated with 10 to 20 parts by weight of the silane coupling agent A), which is a surface treatment agent, is previously kneaded, or (a) an unsaturated group-containing rubber component ( c) Surface treatment with a silica-based filler having a BET specific surface area of 20 to 300 m ² / g and (b) a silane coupling agent A) that is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of the silica-based filler. By mixing the surface-treated silica filler thus prepared, (a) blending of the silica filler having a BET specific surface area of 20 to 300 m ² / g into the unsaturated group-containing rubber component It is preferable at the point which can improve the uptake | capture speed of an agent.
Specifically, the surface treatment was performed with (a) an unsaturated group-containing rubber component and (b) a silane coupling agent A) that is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of the silica-based filler. After kneading the silica filler, (c) a method for producing a rubber composition in which a silica filler having a BET specific surface area of 20 to 300 m ² / g and (d) a silane coupling agent are mixed and kneaded, or (a) (B) a surface-treated silica filler surface-treated with a silane coupling agent A) which is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of a silica-based filler, and (c) BET at least part of the silica-based filler is a specific surface area of 20 to 300 m ² / g after kneading, (c) silica filler has a BET specific surface area of 20 to 300 m ² / g And (d) method for producing a rubber composition compounded by kneading a silane coupling agent can be exemplified.

  The rubber composition of the present invention may further contain a crosslinking agent. Examples of the crosslinking agent used in the present invention include sulfur, selenium, organic peroxide, morpholine disulfide, thiuram compound, and oxime compound. Crosslinking agents are particularly preferred, but are not limited to these.

  The content of the crosslinking agent is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the (a) unsaturated group-containing rubber. It is particularly preferable to contain 0.5 to 5 parts by weight.

  In the production of the rubber composition for cross-linking of the present invention, it is preferable to add the above-mentioned cross-linking agent to the rubber composition of the present invention and knead it at less than 140 ° C.

  The rubber composition for crosslinking thus prepared is molded into an intended shape by an extruder, a calender roll, or a press, and is preferably heated at 140 to 240 ° C. for 1 minute to 3 hours to obtain a crosslinked product. In addition, a mold may be used for crosslinking.

   Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples without departing from the gist thereof.

  The compounding agents used in Examples and Comparative Examples are shown below.

* 1 “SL552” manufactured by JSR Corporation
* 2 “BR01” manufactured by JSR Corporation
* 3 “Nipsil AQ” manufactured by Tosoh Silica Co., Ltd. BET specific surface area 215 m ² / g
* 4 “Cabras NSW-134G” manufactured by Daiso Corporation
BET specific surface area of raw silica 197 m ² / g, surface treatment agent residue rate 0.02
A product obtained by reacting 15 parts by weight of CABRUS-4 with 100 parts by weight of the above silica * 5 “Cabras SW-134” manufactured by Daiso Corporation
BET specific surface area of raw material silica 118m ² / g, surface treatment agent residue rate 0.01
A product obtained by reacting 100 parts by weight of silica with 15 parts by weight of CABRUS-4 * 6 “Sunthene415” manufactured by Nippon Sun Oil Co., Ltd.
* 7 “Sakura stearate” manufactured by NOF Corporation
* 8 “NOCRACK PA” manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 9 “Cabras 2” manufactured by Daiso Corporation
* 10 “Zinc oxide No. 2” manufactured by Sakai Chemical Industry Co., Ltd.
* 11 “Noxeller D” manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 12 “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 13 "Colloidal sulfur" manufactured by Tsurumi Chemical Co., Ltd.
* 14 “Seast 6” manufactured by Tokai Carbon Co., Ltd.

攪拌子を入れた１００ｍｌのガラス瓶に表面処理シリカ１０．０ｇを秤量し、メチルエチルケトン（２−ブタノン）を５０ｍｌ添加してマグネティックスターラーにて５００ｒｐｍで１０分間攪拌した。それをＮｏ．５Ｃの濾紙にて減圧濾過し、残渣を５ｍｌのメチルエチルケトンで５回リンスして残存する溶液を洗浄した。この濾液をロータリーエバポレーターにて１０ｔｏｌｌ、６５℃の条件で３０分間減圧濃縮し、その濃縮残渣の重量から溶媒抽出量を求めた。 Production of surface-treated silica-based fillers The surface-treated silica-based fillers used in Examples 4 and 6 and Comparative Example 4 are those described in the following production examples. In addition, the following solvent extraction test was done and the residue rate with respect to 100 weight part of surface treatment silica type fillers was calculated | required from the following formula | equation (1).

In a 100 ml glass bottle containing a stir bar, 10.0 g of surface-treated silica was weighed, 50 ml of methyl ethyl ketone (2-butanone) was added, and the mixture was stirred with a magnetic stirrer at 500 rpm for 10 minutes. No. The residue was rinsed 5 times with 5 ml of methyl ethyl ketone to wash the remaining solution. This filtrate was concentrated under reduced pressure for 30 minutes under conditions of 10 torr and 65 ° C. using a rotary evaporator, and the amount of solvent extraction was determined from the weight of the concentrated residue.

Production Example 1
A 2 L Henschel mixer (Kawata Super Mixer Piccolo) was charged with 200 g of silica (“TOKUSIL233” BET specific surface area 162 m ² / g, manufactured by Oriental Silicas Corporation) and 1 g of DL-lactic acid, and stirred at 600 rpm with bis (3-triethoxy 30 g of silylpropyl) tetrasulfide (“CABRUS-4” manufactured by Daiso Corporation) was added over 1 minute. This was stirred for 1 hour to obtain surface-treated silica. This was designated treated silica 2. The residue rate when used in the test was 0.02.

Production Example 2
A 2 L Henschel mixer (Kawata Super Mixer Piccolo) was charged with 200 g of silica (“Nipsil AQ” BET specific surface area of 215 m ² / g, manufactured by Tosoh Silica Corporation) and 2 g of stearic acid, and stirred at 600 rpm. 30 g of triethoxysilylpropyl) tetrasulfide (“CABRUS-4” manufactured by Daiso Corporation) was added over 1 minute. This was stirred for 1 hour to obtain surface-treated silica. This was designated treated silica 4. The residue rate when used in the test was 0.46.

Production Example 3
A 2 L Henschel mixer (Kawata Super Mixer Piccolo) was charged with 200 g of silica (“Nipsil AQ” BET specific surface area 215 m ² / g manufactured by Tosoh Silica Co., Ltd.) and 1 g of DL-lactic acid. -Triethoxysilylpropyl) tetrasulfide ("CABRUS-4" manufactured by Daiso Corporation) was added over 1 minute. This was stirred for 1 hour to obtain surface-treated silica. This was designated treated silica 5. The residue rate when used in the test was 0.01.

Manufacture of rubber composition First step of kneading compounding (1) based on 22 g of rubber content in 50 ml Brabender with compounding agents shown in compounding (1) to compounding (3) in Tables 1 and 2 Perform for 30 seconds, add the compound (2) to the compound after the first step, then perform the second step of kneading for 30 seconds, add the compound (3) to the compound after the second step, and then knead The third step was performed for 180 seconds. The kneading was performed at a set temperature of Brabender's electric temperature controller at 80 ° C. and the rotor rotation speed at 60 rpm. The temperature at the time of discharge was about 130 ° C. After kneading, it was dumped and cooled on a 6-inch roll cooled by water flow. The above was performed twice and put together. The kneading time was the time after application of the share (torque during kneading), and the time (seconds) until the application of the share after the addition of the compounding agent in the second step was measured. Moreover, the processability test was done with respect to the obtained rubber composition. The results are shown in Tables 3 and 4.

Production of cross-linked rubber composition and cross-linked product Next, the compound (4) shown in Tables 1 and 2 was added to the obtained rubber composition, and after kneading at 30 to 50 ° C. for 10 minutes, the thickness was about 2 mm. A cross-linking property test was performed using the sheet as a cross-linking property test sample. In addition, a viscoelastic property test was performed using a crosslinked sheet obtained by hot press crosslinking the above sheet at 160 ° C. for 20 minutes as a viscoelastic property test sample. The results are shown in Tables 3 and 4.

Processability test The Mooney viscosity (ML _{1 + 4} ) test at 100 ° C. was performed on the uncrosslinked rubber composition in accordance with JIS K6300 using Mooney viscometer AM-3 manufactured by Toyo Seiki Co., Ltd. and L-type rotor.

Crosslinking characteristic test The scorch time (T10) at 160 ° C. was measured using a vulcanization tester FDR manufactured by Ueshima Seisakusho.

Viscoelastic Property Test A test piece having a width of 4 × length of 40 × thickness of 2 mm was punched out from the crosslinked sheet and measured with a DMS6100 manufactured by Seiko Instruments Inc. under an excitation condition of an initial load of 1000 mN, a tensile strain of 10 μm, and 10 Hz. The measurement temperature range was −20 ° C. to 80 ° C., and the temperature was increased at a rate of 2 ° C./min.

The rubber composition of the present invention has an improved filler incorporation rate into the polymer, suggests that it takes less time to take a share after addition of a filler such as silica, leading to improved productivity, and Mooney viscosity. (ML _{1 + 4} ) is low and processability is excellent. Further, the crosslinked product is very preferable because tan δ at 60 ° C., which is an index of low fuel consumption, is reduced, and the decrease in tan δ at 0 ° C. is reduced. (The index is represented by the ratio of tan δ at 60 ° C. and tan δ at 0 ° C., and the larger this value, the better the cross-linked product.)
On the other hand, Comparative Example 1 is a result of a test by a so-called integral blend method, which is a general kneading method in which a polymer, silica, and a coupling agent are kneaded individually. Comparing Comparative Example 1 and Examples, in the second step, it is not preferable because it takes a long time until the share after addition of silica and various compounding agents is applied, and the tan δ at 60 ° C., which is an index of low fuel consumption, is further increased. It is getting worse. Further, in Comparative Example 2 using only the surface-treated surface-treated silica-based filler, the Mooney viscosity (ML _{1 + 4} ) significantly increased, suggesting deterioration of workability. In Comparative Example 3 in which carbon black is used instead of the surface-treated silica filler, the decrease in tan δ at 60 ° C. is insufficient. In Comparative Example 4 using the surface-treated surface-treated silica-based filler in which the amount of the surface treatment agent is not sufficient, the balance of tan δ (0 ° C. tan δ / 60 ° C. tan δ) is not sufficient and desirable characteristics are not exhibited.

  The rubber composition obtained according to the present invention is advantageous in terms of processing such as low viscosity and filler uptake, has excellent scorch properties, and has excellent balance between wet grip and tanδ, which is an index of fuel economy, and crosslinking. Can provide things. Therefore, it is suitable for the production of dynamically used rubber parts such as tire treads and vibration-proof rubbers.

Claims (12)

(A) Surface treated with silane coupling agent A) which is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of silica-based filler with respect to 100 parts by weight of unsaturated group-containing rubber component 5 to 50 parts by weight of the treated silica filler, and (c) a BET specific surface area of 20 to 300 m ² In a method for producing a rubber composition containing 10 to 200 parts by weight of a silica-based filler, and (d) silane coupling agent B) 1 to 30 parts by weight,
  A surface-treated silica-based filler surface-treated with (a) an unsaturated group-containing rubber component and (b) a silane coupling agent A which is a surface-treating agent of 10 to 20 parts by weight with respect to 100 parts by weight of the silica-based filler. After kneading, (c) BET specific surface area of 20 to 300 m ² / G of a silica filler and (d) a silane coupling agent B) are mixed and kneaded. (A) Surface treated with silane coupling agent A) which is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of silica-based filler with respect to 100 parts by weight of unsaturated group-containing rubber component 5 to 50 parts by weight of the treated silica filler, and (c) a BET specific surface area of 20 to 300 m ² In a method for producing a rubber composition containing 10 to 200 parts by weight of a silica-based filler, and (d) silane coupling agent B) 1 to 30 parts by weight,
(A) an unsaturated group-containing rubber component, (b) a surface-treated silica filler that has been surface-treated with a silane coupling agent A) that is 10 to 20 parts by weight of the surface treatment agent with respect to 100 parts by weight of the silica-based filler, and (C) BET specific surface area of 20 to 300 m ² (C) BET specific surface area of 20 to 300 m after kneading a part of the silica filler that is / g ² / G of a silica filler and (d) a silane coupling agent B) are mixed and kneaded. The method for producing a rubber composition according to claim 1 or 2 , wherein the silane coupling agent A) which is the surface treatment agent is a silane coupling agent represented by the following general formula (I).

Wherein R ¹ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ³ is a divalent hydrocarbon group having 1 to 9 carbon atoms, x is 2 to 6, and _Y is an integer of 0, 1, or 2. The method for producing a rubber composition according to claim 1 or 2 , wherein the silane coupling agent A) which is the surface treatment agent is a silane coupling agent represented by the following general formula (II).

Wherein R ⁴ is a monovalent alkoxy group having 1 to ⁴ carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁶ is a divalent hydrocarbon group having 1 to 9 carbon atoms, and _Y is an integer of 0, 1, or 2.) The method for producing a rubber composition according to claim 1 or 2 , wherein the silane coupling agent A) as the surface treatment agent is a silane coupling agent represented by the following general formula (III).

(In the formula, R ⁷ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁸ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁹ is a divalent hydrocarbon group having 1 to 9 carbon atoms, R ¹⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and _Y is an integer of 0, 1, or 2. The rubber composition according to claim 1 or 2 , wherein the silane coupling agent A) which is the surface treatment agent is a combination of two or more selected from the general formulas (I), (II) and (III) . Manufacturing method .

Wherein R ¹ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ³ is a divalent hydrocarbon group having 1 to 9 carbon atoms, x is 2 to 6, and _Y is an integer of 0, 1, or 2.

Wherein R ⁴ is a monovalent alkoxy group having 1 to ⁴ carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁶ is a divalent hydrocarbon group having 1 to 9 carbon atoms, and _Y is an integer of 0, 1, or 2.)

(In the formula, R ⁷ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁸ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁹ is a divalent hydrocarbon group having 1 to 9 carbon atoms, R ¹⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and _Y is an integer of 0, 1, or 2. The method for producing a rubber composition according to any one of claims 1 to 6, wherein (d) the silane coupling agent B) is at least one selected from general formulas (I), (II) and (III). .

Wherein R ¹ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ³ is a divalent hydrocarbon group having 1 to 9 carbon atoms, x is 2 to 6, and _Y is an integer of 0, 1, or 2.

Wherein R ⁴ is a monovalent alkoxy group having 1 to ⁴ carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁶ is a divalent hydrocarbon group having 1 to 9 carbon atoms, and _Y is an integer of 0, 1, or 2.)

(In the formula, R ⁷ is a monovalent alkoxy group having 1 to 4 carbon atoms or a polyalkylene glycol monoalkyl ether group having 3 to 40 carbon atoms, R ⁸ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ⁹ is a divalent hydrocarbon group having 1 to 9 carbon atoms, R ¹⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and _Y is an integer of 0, 1, or 2. (B) When 100 parts by weight of the surface-treated silica filler surface-treated with a silane coupling agent A) that is 10 to 20 parts by weight of the surface treatment agent with respect to 100 parts by weight of the silica filler is subjected to an extraction treatment, The method for producing a rubber composition according to any one of claims 1 to 7 , wherein a value obtained by the formula (1) is 0.4 or less.

The method for producing a rubber composition according to any one of claims 1 to 8 , wherein the surface treatment agent is only a sulfur-containing silane coupling agent. (B) The surface-treated silica-based filler that has been surface-treated with a silane coupling agent A) that is 10 to 20 parts by weight of the surface-treating agent with respect to 100 parts by weight of the silica-based filler is obtained by adding a hydroxy acid. Item 10. A method for producing a rubber composition according to any one of Items 1 to 9 . (A) Surface treated with silane coupling agent A) which is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of silica-based filler with respect to 100 parts by weight of unsaturated group-containing rubber component 5 to 50 parts by weight of the treated silica filler, and (c) a BET specific surface area of 20 to 300 m ² In the method for producing a crosslinked product obtained by crosslinking a rubber composition containing 10 to 200 parts by weight of a silica filler / g and (d) silane coupling agent B) 1 to 30 parts by weight,
  A surface-treated silica-based filler surface-treated with (a) an unsaturated group-containing rubber component and (b) a silane coupling agent A which is a surface-treating agent of 10 to 20 parts by weight with respect to 100 parts by weight of the silica-based filler. After kneading, (c) BET specific surface area of 20 to 300 m ² A step of obtaining a rubber composition for blending and kneading the silica-based filler that is / g and (d) the silane coupling agent B),
  Adding a crosslinking agent to the rubber composition;
  A method for producing a crosslinked product, comprising a step of crosslinking a rubber composition. (A) Surface treated with silane coupling agent A) which is a surface treatment agent of 10 to 20 parts by weight with respect to 100 parts by weight of silica-based filler with respect to 100 parts by weight of unsaturated group-containing rubber component 5 to 50 parts by weight of the treated silica filler, and (c) a BET specific surface area of 20 to 300 m ² In the method for producing a crosslinked product obtained by crosslinking a rubber composition containing 10 to 200 parts by weight of a silica filler / g and (d) silane coupling agent B) 1 to 30 parts by weight,
(A) an unsaturated group-containing rubber component, (b) a surface-treated silica filler that has been surface-treated with a silane coupling agent A) that is 10 to 20 parts by weight of the surface treatment agent with respect to 100 parts by weight of the silica-based filler, and (C) BET specific surface area of 20 to 300 m ² (C) BET specific surface area of 20 to 300 m after kneading a part of the silica filler that is / g ² A step of obtaining a rubber composition for blending and kneading the silica-based filler that is / g and (d) the silane coupling agent B),
  Adding a crosslinking agent to the rubber composition;
  A method for producing a crosslinked product, comprising a step of crosslinking a rubber composition.