JP7059702B2 - Rubber composition for tires and pneumatic tires - Google Patents

Description

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

In recent years, improvement of wet grip performance (braking performance on wet road surface) has been required from the viewpoint of safety when the vehicle is running. On the other hand, there is known a method of blending silica with a rubber component constituting a tread portion of a tire to improve wet grip performance.
However, since silica has a low affinity with the rubber component and has high cohesiveness between silicas, even if silica is simply mixed with the rubber component, the silica does not disperse, and the effect of improving the wet grip performance is sufficient. There was a problem that it could not be obtained.

Under such circumstances, claim 1 of Patent Document 1 discloses a rubber composition for a tire containing a diene-based rubber, silica, and a resin having an α-methylstyrene unit. Further, Patent Document 1 describes that silica is dispersed at a high level in the rubber composition and exhibits excellent wet grip performance.

Japanese Unexamined Patent Publication No. 2016-89118

On the other hand, in recent years, further improvement of the wet grip performance of the tire is desired in order to improve safety and the like. In particular, competitive wet tires are required to have an extremely high level of wet grip performance. At the same time, it is also required that the above-mentioned wet grip performance is exhibited (excellent in operability) as soon as possible during operation. Further, tires (particularly competitive wet tires) are required to have high breaking elongation and high breaking strength in addition to the above-mentioned wet grip performance. Further, when the rubber composition for a tire is usually made into a sheet by using two rolls, it is also required that the work such as turning back can be smoothly performed (excellent in sheet property).

When the present inventor has studied the rubber composition for tires described in Patent Document 1, it is not always possible to obtain a composition that satisfies all of wet grip performance, operability, sheet property, breaking elongation and breaking strength at a high level. It became clear. In particular, the level of sheet property was low, and it became clear that this point was extremely problematic.

Therefore, the present invention provides a rubber composition for a tire having excellent wet grip performance, operability and seating property, and having high breaking elongation and breaking strength, and a pneumatic tire using the above rubber composition for a tire. That is the issue.

As a result of diligent studies on the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by blending an organosilicon compound having a specific structure or the like in a specific ratio, and has reached the present invention.
That is, the present inventor has found that the above problem can be solved by the following configuration.

(1) A diene-based rubber containing at least an aromatic vinyl-conjugated diene copolymer rubber, silica, a resin having a softening point of 80 to 160 ° C., a silane coupling agent, and a formula (I) described later. Contains organosilicon compounds
The silica content is 120 parts by mass or more with respect to 100 parts by mass of the diene rubber.
The content of the resin is 10 to 60 parts by mass with respect to 100 parts by mass of the diene rubber.
A rubber composition for a tire, wherein the content of the organosilicon compound is 1 to 20% by mass with respect to the content of silica.
(2) The rubber composition for a tire according to (1) above, wherein the resin has a repeating unit derived from α-methylstyrene.
(3) The silane coupling agent is a polysiloxane represented by the average composition formula of the formula (1) described later.
The rubber composition for a tire according to the above (1) or (2), wherein the content of the silane coupling agent is 2 to 20% by mass with respect to the content of the silica.
(4) A pneumatic tire using the rubber composition for a tire according to any one of (1) to (3) above.

As shown below, according to the present invention, a tire rubber composition having excellent wet grip performance, operability and seating properties, and having high breaking elongation and breaking strength, and the above-mentioned rubber composition for tires were used. Pneumatic tires can be provided.

It is a partial cross-sectional schematic diagram of an example of embodiment of the pneumatic tire of this invention.

Hereinafter, the rubber composition for a tire of the present invention and the pneumatic tire using the rubber composition for a tire will be described.
The numerical range represented by using "-" in the present specification means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
In addition, each component contained in the rubber composition for a tire of the present invention may be used alone or in combination of two or more. Here, when two or more kinds of each component are used in combination, the content of the component means the total content unless otherwise specified.

[1] Rubber Composition for Tires The rubber composition for tires of the present invention (hereinafter, also referred to as “composition of the present invention”) comprises a diene-based rubber containing at least an aromatic vinyl-conjugated diene copolymer rubber and silica. It contains a resin having a softening point of 80 to 160 ° C., a silane coupling agent, and an organic silicon compound represented by the formula (I) described later.
Here, the content of the silica is 120 parts by mass or more with respect to 100 parts by mass of the diene rubber, and the content of the resin is 10 to 60 parts by mass with respect to 100 parts by mass of the diene rubber. The content of the organic silicon compound is 1 to 20% by mass with respect to the content of the silica.

Since the composition of the present invention has such a structure, it is considered that the above-mentioned effects can be obtained. The reason is not clear, but it is presumed to be as follows.

From the study of the present inventor, it is known that various physical properties such as viscosity, strength, and tack (stickiness) of the rubber composition affect the sheet properties. And it is known that excellent sheet properties are realized by balancing these physical properties. For example, if the viscosity is simply lowered, the strength is also lowered, and there is a problem that the rubber composition sticks to both rolls due to losing the tack.
On the other hand, since the composition of the present invention contains a specific resin, an organosilicon compound having a specific structure, and the like in a predetermined ratio, the above-mentioned balance of physical properties is achieved, and as a result, excellent sheet properties are exhibited. It is presumed.

Hereinafter, each component contained in the composition of the present invention will be described in detail.

[Diene rubber]
The diene-based rubber contained in the composition of the present invention contains at least an aromatic vinyl-conjugated diene copolymer rubber.
The content of the aromatic vinyl-conjugated diene copolymer rubber in the diene-based rubber is preferably 30% by mass or more, more preferably 50% by mass or more, for the reason that the effect of the present invention is more excellent. It is more preferably 70% by mass or more, and particularly preferably 90% by mass or more. The upper limit is not particularly limited and is 100% by mass.

Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene-butadiene copolymer rubber (SBR) and styrene-isoprene copolymer rubber. Of these, styrene-butadiene copolymer rubber (SBR) is preferable because the effect of the present invention is more excellent.

The aromatic vinyl content (ratio of repeating units derived from aromatic vinyl (eg, styrene)) of the aromatic vinyl-conjugated diene copolymer is 10 to 50% by mass because the effect of the present invention is more excellent. It is preferably 20 to 40% by mass, and more preferably 20 to 40% by mass.
Further, the amount of vinyl bonded in the conjugated diene of the aromatic vinyl-conjugated diene copolymer is preferably 30 to 80%, preferably 50 to 70%, for the reason that the effect of the present invention is more excellent. More preferred. Here, the vinyl bond amount is the ratio of 1,2-vinyl bond among cis-1,4-bond, trans-1,4-bond and 1,2-vinyl bond, which are the bonding modes of conjugated diene. say.

The aromatic vinyl-conjugated diene copolymer rubber is not particularly limited in its production method, and can be produced by a conventionally known method.
Further, the aromatic vinyl and the conjugated diene as the monomer used in producing the aromatic vinyl-conjugated diene copolymer rubber are not particularly limited.
Here, examples of the conjugated diene monomer include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and 2-chloro-1. , 3-butadiene, 1,3-pentadiene and the like.
On the other hand, examples of the aromatic vinyl monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, and 2,4-diisopropylstyrene. Examples thereof include 4-tert-butylstyrene, divinylbenzene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N, N-dimethylaminoethylstyrene, vinylpyridine and the like.

The diene-based rubber may further contain a diene-based rubber other than the aromatic vinyl-conjugated diene copolymer rubber.
Examples of such diene-based rubbers include natural rubber (NR), butadiene rubber (BR), isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), and halogenated butyl rubber (Br-). IIR, Cl-IIR), chloroprene rubber (CR) and the like.

The weight average molecular weight (Mw) of the diene-based rubber contained in the composition of the present invention is preferably 100,000 to 10,000,000, preferably 300,000 to 10,000, for the reason that the effect of the present invention is more excellent. More preferably, it is 3,000,000.
The number average molecular weight (Mn) of the diene-based rubber contained in the composition of the present invention is 50,000 or more. Among them, for the reason that the effect of the present invention is more excellent, it is preferably 5,000,000 or less, and more preferably 150,000 to 1,500,000.
It is preferable that the Mw and / or Mn of at least one diene rubber contained in the diene rubber is included in the above range, and the Mw and / or Mn of all the diene rubbers contained in the diene rubber is described above. It is more preferable to be included in the range.

In the present specification, Mw and Mn are standard polystyrene-equivalent values obtained by gel permeation chromatography (GPC) measurement under the following conditions.
・ Solvent: Tetrahydrofuran ・ Detector: RI detector

[silica]
The silica contained in the composition of the present invention is not particularly limited, and any conventionally known silica can be used. Specific examples of the silica include wet silica, dry silica, fumed silica, diatomaceous earth and the like.

The cetyltrimethylammonium bromide (CTAB) adsorption specific surface area (hereinafter, “CTAB adsorption specific surface area” is also simply referred to as “CTAB”) of the silica is not particularly limited, but 100 to 300 m ² for the reason that the effect of the present invention is more excellent. It is preferably / g, and more preferably 150 to 200 m ² / g.
Here, the CTAB adsorption specific surface area is a value obtained by measuring the amount of CTAB adsorbed on the silica surface according to JIS K6217-3: 2001 "Part 3: How to obtain the specific surface area-CTAB adsorption method".

In the composition of the present invention, the content of silica is 120 parts by mass or more with respect to 100 parts by mass of the above-mentioned rubber component. The upper limit is not particularly limited, but is preferably 200 parts by mass or less, and more preferably 150 parts by mass or less, for the reason that the effect of the present invention is more excellent.

[Specific resin]
As described above, the composition of the present invention contains a resin having a softening point of 80 to 160 ° C. (hereinafter, also referred to as “specific resin”). The softening point of the specific resin is preferably 100 to 150 ° C. for the reason that the effect of the present invention is more excellent.
The softening point is measured in accordance with JIS K6220-1.

The specific resin is a resin having a repeating unit derived from α-methylstyrene, a terpene resin, an aromatic-modified terpene resin, a terpene phenol resin, a hydrogenated terpene phenol resin, a hydrogenated terpan resin, because the effect of the present invention is more excellent. Or, it is preferably a hydrogenated aromatic-modified terpene resin, and more preferably a resin having a repeating unit derived from α-methylstyrene.

The resin having a repeating unit derived from α-methylstyrene may have a repeating unit other than the repeating unit derived from α-methylstyrene. Such repeating units include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3, Repeating units derived from aromatic hydrocarbon-based monomers such as 5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene and the like can be mentioned.

The resin having a repeating unit derived from α-methylstyrene is preferably an α-methylstyrene homopolymer or an α-methylstyrene-styrene copolymer because the effect of the present invention is more excellent.

The weight average molecular weight (Mw) of the specific resin is not particularly limited, but the polystyrene-equivalent value measured by gel permeation chromatography (GPC) is preferably 1000 to 10000, and more preferably 1500 to 8000. ..

The specific resins are FTR-7100 (softening point 100 ° C., manufactured by Mitsui Chemical Company, Inc.) as a styrene- (α-methylstyrene) -aliphatic hydrocarbon-based polymer, and FTR-0100 as an α-methylstyrene-based polymer. (Softening point 100 ° C., manufactured by Mitsui Chemical Co., Ltd.), FTR-2120 (softening point 120 ° C., manufactured by Mitsui Chemical Co., Ltd.) as a styrene- (α-methylstyrene) -based copolymer, FTR-2140 (softening point 145 ° C., Mitsui Chemicals Co., Ltd.), Crystalx 3100 (softening point 100 ° C, Eastman Chemical Co., Ltd.), Crystalx 3085 (softening point 85 ° C, Eastman Chemical Co., Ltd.), Crystalx 5140 (softening point 140 ° C, Eastman Chemical Co., Ltd.) , Crystalx 1120 (softening point 120 ° C, manufactured by Eastman Chemical Company), Crystalx F85 (softening point 85 ° C, manufactured by Eastman Chemical Company), Crystalx F100 (softening point 100 ° C., manufactured by Eastman Chemical Company) ) And Crystalex F115 (softening point 115 ° C., manufactured by Eastman Chemical Company) and the like can be used.

In the composition of the present invention, the content of the specific resin is 10 to 60 parts by mass with respect to 100 parts by mass of the rubber component described above. Among them, 20 to 50 parts by mass is preferable because the effect of the present invention is more excellent.

[Silane coupling agent]
The silane coupling agent contained in the composition of the present invention is not particularly limited as long as it is a silane compound having a hydrolyzable group and an organic functional group.
The hydrolyzable group is not particularly limited, and examples thereof include an alkoxy group, a phenoxy group, a carboxyl group, and an alkenyloxy group. Of these, an alkoxy group is preferable because the effect of the present invention is more excellent. When the hydrolyzable group is an alkoxy group, the number of carbon atoms of the alkoxy group is preferably 1 to 16 and more preferably 1 to 4 for the reason that the effect of the present invention is more excellent. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group and the like.

The above organic functional group is not particularly limited, but is preferably a group capable of forming a chemical bond with an organic compound, for example, an epoxy group, a vinyl group, an acryloyl group, a methacryloyl group, an amino group, a sulfide group, a mercapto group, or a block. Examples thereof include a mercapto group (protected mercapto group) (for example, an octanoylthio group), and among them, a sulfide group (particularly, a disulfide group and a tetrasulfide group), a mercapto group, and a block mercapto group for the reason that the effect of the present invention is more excellent. Is preferable.

Specific examples of the above silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, and mercaptopropyltrimethoxy. Silane, Mercaptopropyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazoletetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilyl Examples thereof include propyl-N, N-dimethylthiocarbamoyl-tetrasulfide, 3-octanoylthio-1-propyltriethoxysilane, and one of these may be used alone or in combination of two or more. ..

The silane coupling agent is preferably a sulfur-containing silane coupling agent, and more preferably a mercapto-based silane coupling agent (silane coupling agent having a mercapto group), because the effect of the present invention is more excellent. It is preferable that it is a polysiloxane (specific polysiloxane) represented by the average composition formula of the formula (1) described later.

[Specific polysiloxane]
The specific polysiloxane is a polysiloxane represented by the average composition formula of the following formula (1).
(A) _a (B) _b (C) _c (D) _d (R ¹ ) _e SiO _{(4-2a-b-c-d-e) / 2} (1)

In the above formula (1), A represents a divalent organic group containing a sulfide group. B represents a monovalent hydrocarbon group having 5 to 10 carbon atoms. C represents a hydrolyzable group. D represents an organic group containing a mercapto group. R ¹ represents a monovalent hydrocarbon group having 1 to 4 carbon atoms. a to e satisfy the relational expression of 0 ≦ a <1, 0 <b <1, 0 <c <3, 0 <d <1, 0 ≦ e <2, 0 <2a + b + c + d + e <4.

Formula (1) represents the average composition of polysiloxane. That is, it represents the type of groups directly bonded to the Si atom of polysiloxane and the average number of each group.
Si in the formula (1) represents a Si atom of polysiloxane. Further, O in the formula (1) represents an O atom of polysiloxane. The O atom is a divalent group and is always bonded to two Si atoms (Si atoms of polysiloxane). (4-2ab-c-de) / 2 in the formula (1) represents the average number of O atoms of the polysiloxane bonded to the Si atom of the polysiloxane.
A, B, C, D and R ¹ in the formula (1) all represent a group bonded to the Si atom of the polysiloxane. Note that A is a divalent group and is always bonded to two Si atoms (Si atoms of polysiloxane). A, b, c, d and e in the formula (1) represent the average number of A, B, C, D and ^R1 bonded to the Si atom of the polysiloxane, respectively.
Since the total (a × 2 + b + c + d + e + ((4-2a-b-c-d-e) / 2) × 2) of each group directly bonded to the Si atom of the polysiloxane becomes 4 (the valence of the Si atom). As can be seen, groups other than A, B, C, D, ^R1 and O are not directly bonded to the Si atom of the polysiloxane. In the above total calculation, a and (4-2abc-d-e) / 2) are doubled because A and O are divalent groups.

In the above formula (1), A represents a divalent organic group containing a sulfide group (hereinafter, also referred to as “sulfide group-containing organic group”). Among them, the group represented by the following formula (2) is preferable because the effect of the present invention is more excellent.
^* -(CH ₂ ) _n -S _x- (CH ₂ ) _n- ^* (2)
In the above formula (2), n represents an integer of 1 to 10, and among them, an integer of 2 to 4 is preferable because the effect of the present invention is more excellent.
In the above equation (2), x represents an integer of 1 to 6, and among them, an integer of 2 or more is preferable, and an integer of 2 to 4 is more preferable because the effect of the present invention is more excellent. preferable.
In the above equation (2), * indicates a bonding position.
Specific examples of the group represented by the above formula (2) include, for example, ^* -CH ₂ -S ₂ -CH _2- ^* , ^* -C ₂ H ₄ -S ₂ -C ₂ H _4- ^* , ^* -. C ₃ H ₆ -S ₂ -C ₃ H _6- ^* , ^* -C ₄ H ₈ -S ₂ -C ₄ H _8- ^* , ^* -CH ₂ -S ₄ -CH _2- ^* , ^* -C ₂ H ₄ -S ₄ -C ₂ H _4- ^* , ^* -C ₃ H ₆ -S ₄ -C ₃ H _6- ^* , ^* -C ₄ H ₈ -S ₄ -C ₄ H _8- ^* , etc. can be mentioned.
For the reason that the effect of the present invention is more excellent, the sulfide group contained in A is preferably a tetrasulfide group (-S _4- ).

In the above formula (1), B represents a monovalent hydrocarbon group (preferably an alkyl group) having 5 to 10 carbon atoms, and specific examples thereof include a hexyl group, an octyl group, a decyl group and the like. Be done.

In the above formula (1), C represents a hydrolyzable group, and specific examples thereof include an alkoxy group, a phenoxy group, a carboxyl group, and an alkenyloxy group. Among them, the group represented by the following formula (3) is preferable because the effect of the present invention is more excellent.
^* -OR ² (3)
In the above formula (3), R ² is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 6 to 10 carbon atoms (arylalkyl group), or an alkenyl group having 2 to 10 carbon atoms. Of these, an alkyl group having 1 to 5 carbon atoms is preferable because the effect of the present invention is more excellent. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, an octadecyl group and the like. Specific examples of the aryl group having 6 to 10 carbon atoms include a phenyl group and a tolyl group. Specific examples of the aralkyl group having 6 to 10 carbon atoms include a benzyl group and a phenylethyl group. Specific examples of the alkenyl group having 2 to 10 carbon atoms include a vinyl group, a propenyl group, a pentenyl group and the like.
In the above formula (3), * indicates a bonding position.

In the above formula (1), D represents an organic group containing a mercapto group. Among them, the group represented by the following formula (4) is preferable because the effect of the present invention is more excellent.
^* -(CH ₂ ) _m -SH (4)
In the above formula (4), m represents an integer of 1 to 10, and among them, an integer of 1 to 5 is preferable because the effect of the present invention is more excellent.
In the above equation (4), * indicates a bonding position.
Specific examples of the group represented by the above formula (4) include ^* -CH ₂ SH, ^* -C ₂ H ₄ SH, ^* -C ₃ H ₆ SH, ^* -C ₄ H ₈ SH, ^* -C ₅ Examples include H ₁₀ SH, ^* -C ₆ H ₁₂ SH, ^* -C ₇ H ₁₄ SH, ^* -C ₈ H ₁₆ SH, ^* -C ₉ H ₁₈ SH, and ^* -C ₁₀ H ₂₀ SH.

In the above formula (1), E represents a monovalent hydrocarbon group having 1 to 4 carbon atoms.

In the above equation (1), a to e are relational expressions of 0≤a <1, 0 <b <1, 0 <c <3, 0 <d <1, 0≤e <2, 0 <2a + b + c + d + e <4. Meet.

The specific polysiloxane preferably has a larger than 0 (0 <a) because the effect of the present invention is more excellent. That is, it is preferable to have a sulfide group-containing organic group. Above all, 0 <a ≦ 0.50 is preferable because the effect of the present invention is more excellent.

In the above formula (1), b is preferably 0.10 ≦ b ≦ 0.89 for the reason that the effect of the present invention is more excellent.
In the above formula (1), c is preferably 1.2 ≦ c ≦ 2.0 because the effect of the present invention is more excellent.
In the above formula (1), d is preferably 0.1 ≦ d ≦ 0.8 for the reason that the effect of the present invention is more excellent.

In the specific polysiloxane, A is a group represented by the above formula (2) in the above formula (1), and C in the above formula (1) is the above formula (1) because the effect of the present invention is more excellent. It is a group represented by 3), and it is preferable that D in the above formula (1) is a polysiloxane which is a group represented by the above formula (4).

The weight average molecular weight of the specific polysiloxane is preferably 500 to 2300, more preferably 600 to 1500, for the reason that the effect of the present invention is more excellent. The molecular weight of the specific polysiloxane in the present application is determined in terms of polystyrene by gel permeation chromatography (GPC) using toluene as a solvent.
The mercapto equivalent of the specific polysiloxane by the addition of acetic acid / potassium iodide / potassium iodate-sodium thiosulfate solution titration method is preferably 550 to 700 g / mol, preferably 600 to 700 g / mol, from the viewpoint of excellent sulfide reactivity. It is more preferably 650 g / mol.

The specific polysiloxane preferably has 2 to 50 siloxane units (—Si—O—) for the reason that the effect of the present invention is more excellent.

The skeleton of the specific polysiloxane does not contain any metal other than the silicon atom (for example, Sn, Ti, Al).

The method for producing the specific polysiloxane is not particularly limited, but as a first preferred embodiment, an organosilicon compound represented by the following formula (6) and an organosilicon compound represented by the following formula (7) are used. Can be mentioned as a method of hydrolyzing and condensing. Further, as a second preferred embodiment, the organosilicon compound represented by the following formula (5), the organosilicon compound represented by the following formula (6), and the organosilicon represented by the following formula (7) are used. Examples thereof include a method of hydrolyzing and condensing with a compound. Further, as a third preferred embodiment, the organosilicon compound represented by the following formula (5), the organosilicon compound represented by the following formula (6), and the organosilicon represented by the following formula (7) are used. Examples thereof include a method of hydrolyzing and condensing the compound and the organosilicon compound represented by the following formula (8).
Among them, the second preferred embodiment is preferable because the effect of the present invention is more excellent.

In the above formula (5), R ⁵¹ represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and the reason why the effect of the present invention is more excellent. Therefore, it is preferably an alkyl group having 1 to 5 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, an octadecyl group and the like. Specific examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a tolyl group, and a naphthyl group. Specific examples of the alkenyl group having 2 to 10 carbon atoms include a vinyl group, a propenyl group, a pentenyl group and the like.
In the above formula (5), R ⁵² represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. Specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group and the like. Specific examples of the aryl group having 6 to 10 carbon atoms are the same as those of R ⁵¹ .
In the above formula (5), the definition of n and the preferred embodiment are the same as those of the above n.
In the above formula (5), the definition of x and the preferred embodiment are the same as the above x.
In the above equation (5), y represents an integer of 1 to 3.

Specific examples of the organic silicon compound represented by the above formula (5) include bis (trimethoxysilylpropyl) tetrasulfide, bis (triethoxysilylpropyl) tetrasulfide, bis (trimethoxysilylpropyl) disulfide, and bis. (Triethoxysilylpropyl) Disulfide and the like can be mentioned.

In the above formula (6), the definition, specific examples and preferred embodiments of R ⁶¹ are the same as those of R ⁵¹ .
In the above formula (6), the definition, the specific example, and the preferred embodiment of R ⁶² are the same as those of R ⁵² .
In the above equation (6), the definition of z is the same as the above y.
In the above equation (6), p represents an integer of 5 to 10.

Specific examples of the organosilicon compound represented by the above formula (6) include, for example, pentiltrimethoxysilane, pentylmethyldimethoxysilane, pentiltriethoxysilane, pentylmethyldiethoxysilane, hexyltrimethoxysilane, and hexylmethyldimethoxysilane. , Hexiltriethoxysilane, hexylmethyldiethoxysilane, octylmethyldimethoxysilane, octylmethyldimethoxysilane, octylmethyldiethoxysilane, octylmethyldiethoxysilane, decyltrimethoxysilane, decylmethyldimethoxysilane, decyltriethoxysilane, decylmethyl Examples thereof include diethoxysilane.

In the above formula (7), the definition, specific examples and preferred embodiments of R ⁷¹ are the same as those of R ⁵¹ .
In the above formula (7), the definition, the specific example, and the preferred embodiment of R ⁷² are the same as those of R ⁵² .
In the above formula (7), the definition of m and the preferred embodiment are the same as the above m.
In the above equation (7), the definition of w is the same as the above y.

Specific examples of the organic silicon compound represented by the above formula (7) include α-mercaptomethyltrimethoxysilane, α-mercaptomethylmethyldimethoxysilane, α-mercaptomethyltriethoxysilane, and α-mercaptomethylmethyldi. Examples thereof include ethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldiethoxysilane.

In the above formula (8), the definition, the specific example and the preferred embodiment of R ⁸¹ are the same as those of the above R ⁵¹ .
In the above formula (8), the definition, the specific example, and the preferred embodiment of R ⁸² are the same as those of R ⁵² .
In the above equation (8), the definition of v is the same as the above y.
In the above equation (8), q represents an integer of 1 to 4.

Specific examples of the organic silicon compound represented by the above formula (8) include, for example, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, methylethyldiethoxysilane, propyltrimethoxysilane, propylmethyldimethoxysilane, and the like. Examples thereof include propylmethyldiethoxysilane.

When producing the above-mentioned specific polysiloxane, a solvent may be used if necessary. The solvent is not particularly limited, but specifically, an aliphatic hydrocarbon solvent such as pentane, hexane, heptane, and decane, an ether solvent such as diethyl ether, tetrahydrofuran, and 1,4-dioxane, formamide, dimethylformamide, and N. -Examples include amide-based solvents such as methylpyrrolidone, aromatic hydrocarbon-based solvents such as benzene, toluene and xylene, and alcohol-based solvents such as methanol, ethanol and propanol.

When producing the above-mentioned specific polysiloxane, a catalyst may be used if necessary. Examples of the catalyst include an acidic catalyst such as hydrochloric acid and acetic acid, a Lewis acid catalyst such as ammonium fluoride, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium acetate, potassium acetate, sodium hydrogencarbonate, potassium carbonate, and potassium hydrogencarbonate. , Alkali metal salts such as calcium carbonate, sodium methoxydo and sodium ethoxydo, amine compounds such as triethylamine, tributylamine, pyridine and 4-dimethylaminopyridine and the like.
The catalyst is preferably not an organometallic compound containing Sn, Ti or Al as a metal. When such an organic metal compound is used, a metal is introduced into the polysiloxane skeleton to obtain the specific polysiloxane (a metal other than a silicon atom (for example, Sn, Ti, Al) does not exist in the skeleton). It may not be possible.

As the organosilicon compound used in producing the specific polysiloxane, a silane coupling agent having a mercapto group [for example, an organosilicon compound represented by the formula (7)] and a silane cup having a sulfide group or a mercapto group. When a silane coupling agent other than the ring agent [for example, an organosilicon compound represented by the formula (6) or the formula (8)] is used in combination, the silane coupling agent having a mercapto group and the silane having a sulfide group or a mercapto group are used in combination. The mixing ratio (molar ratio) with a silane coupling agent other than the coupling agent (silane coupling agent having a mercapto group / silane coupling agent other than a sulfide group or a silane coupling agent having a mercapto group) is the present invention. For the reason that the effect is more excellent, it is preferably 1.1 / 8.9 to 6.7 / 3.3, and more preferably 1.4 / 8.6 to 5.0 / 5.0.

As the organosilicon compound used in producing the specific polysiloxane, a silane coupling agent having a mercapto group [for example, an organosilicon compound represented by the formula (7)] and a silane coupling agent having a sulfide group [ For example, when an organosilicon compound represented by the formula (5) is used in combination, the mixing ratio (molar ratio) of the silane coupling agent having a mercapto group and the silane coupling agent having a sulfide group (silane having a mercapto group). The coupling agent / silane coupling agent having a sulfide group) is preferably 2.0 / 8.0 to 8.9 / 1.1, preferably 2.5 /, for the reason that the effect of the present invention is more excellent. It is more preferably 7.5 to 8.0 / 2.0.

As the organosilicon compound used in producing the specific polysiloxane, a silane coupling agent having a mercapto group [for example, an organosilicon compound represented by the formula (7)] and a silane coupling agent having a sulfide group [ For example, an organosilicon compound represented by the formula (5) and / or], and a silane coupling agent other than the silane coupling agent having a sulfide group or a mercapto group [for example, represented by the formula (6) or the formula (8). When the organosilicon compound is used in combination, the amount of the silane coupling agent having a mercapto group is preferably 10.0 to 73.0% in the total amount (mol) of the former three. The amount of the silane coupling agent having a sulfide group is preferably 5.0 to 67.0% of the total amount of the former three. The amount of the silane coupling agent other than the silane coupling agent having a sulfide group or a mercapto group is preferably 16.0 to 85.0% of the total amount of the former three.

〔Content〕
In the composition of the present invention, the content of the silane coupling agent is not particularly limited, but for the reason that the effect of the present invention is more excellent, it is preferably 1 to 30% by mass with respect to the above-mentioned silica content. It is more preferably 2 to 20% by mass, and even more preferably 4 to 10% by mass.
Further, in the composition of the present invention, the content of the silane coupling agent is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the above-mentioned diene-based rubber because the effect of the present invention is more excellent. It is more preferably 2 to 20 parts by mass, and even more preferably 4 to 10 parts by mass.

[Specific organosilicon compound]
As described above, the composition of the present invention contains an organosilicon compound represented by the following formula (I) (hereinafter, also referred to as “specific organosilicon compound”).

In the above formula (I), R ¹ represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, and R ² is an alkyl group having 1 to 10 carbon atoms or 6 to 10 carbon atoms. Represents an aryl group, f represents a number greater than or equal to 0, e, g and h represent numbers greater than 0 independently of each other, and m represents an integer of 1 to 3. However, the order of each repeating unit is arbitrary.
When there are a plurality of R ^1s , the plurality of R ^1s may be the same or different. When there are a plurality of R ^2s , the plurality of R ^2s may be the same or different.

The alkyl group having 1 to 10 carbon atoms may be linear, cyclic or branched, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group and an n-. Butyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, cyclopropyl group, cyclobutyl group, Cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like can be mentioned. Among them, a linear alkyl group is preferable, and a methyl group or an ethyl group is more preferable, because the effect of the present invention is more excellent.
Specific examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, an α-naphthyl group, a β-naphthyl group and the like.

The above R ¹ is preferably a linear alkyl group, more preferably a methyl group or an ethyl group, and even more preferably an ethyl group, for the reason that the effect of the present invention is more excellent.

As described above, in formula (I), e represents a number greater than 0 (preferably an integer greater than 0). Among them, for the reason that the effect of the present invention is more excellent, it is preferably 10 or more, more preferably 20 or more, and even more preferably 30 or more. The upper limit is not particularly limited, but is preferably 100 or less, more preferably 80 or less, still more preferably 60 or less, for the reason that the effect of the present invention is more excellent.

As described above, in the formula (I), f represents a number of 0 or more (preferably an integer of 0 or more). The upper limit is not particularly limited, but for the reason that the effect of the present invention is more excellent, it is preferably 20 or less, more preferably 10 or less, further preferably 5 or less, and particularly preferably 1 or less. preferable.

As described above, in formula (I), g represents a number greater than 0 (preferably an integer greater than 0). Among them, 5 or more is preferable, and 10 or more is more preferable, for the reason that the effect of the present invention is more excellent. The upper limit is not particularly limited, but is preferably 50 or less, more preferably 40 or less, still more preferably 30 or less, for the reason that the effect of the present invention is more excellent.

As described above, in formula (I), h represents a number greater than 0 (preferably an integer greater than 0). Among them, 5 or more is preferable, and 10 or more is more preferable, for the reason that the effect of the present invention is more excellent. The upper limit is not particularly limited, but is preferably 100 or less, more preferably 70 or less, still more preferably 40 or less, for the reason that the effect of the present invention is more excellent.

For e, f, g and h in the formula (I), e / (e + f + g + h) is preferably 0.10 to 0.90, and 0.20 to 0. It is more preferably 80, further preferably 0.30 to 0.70, and particularly preferably 0.40 to 0.60.

For e, f, g and h in the formula (I), f / (e + f + g + h) is preferably 0.20 or less, and more preferably 0.10 or less, for the reason that the effect of the present invention is more excellent. preferable. The lower limit is not particularly limited and is 0.

For e, f, g and h in the formula (I), g / (e + f + g + h) is preferably 0.10 to 0.50, and 0.15 to 0. It is more preferably 40, and even more preferably 0.20 to 0.30.

For e, f, g and h in the formula (I), h / (e + f + g + h) is preferably 0.10 to 0.50, and 0.15 to 0. It is more preferably 40, and even more preferably 0.20 to 0.30.

For f and g in the formula (I), g / (f + g) is preferably 0.30 or more, and more preferably 0.70 or more, for the reason that the effect of the present invention is more excellent. The upper limit is not particularly limited and is 1.

For e, f and g in the formula (I), (f + g) / (e + f + g) is preferably 0.10 to 0.50, and 0.20 to 0. It is more preferably 40.

As mentioned above, m represents an integer of 1 to 3. Among them, 2 or 3 is preferable, and 3 is more preferable, because the effect of the present invention is more excellent.

The number average molecular weight (Mn) of the specific organosilicon compound is less than 50,000. Among them, 40,000 or less is preferable, and 20,000 or less is more preferable, for the reason that the effect of the present invention is more excellent. The lower limit is not particularly limited, but is preferably 1,000 or more, and more preferably 5,000 or more, for the reason that the effect of the present invention is more excellent.

The above-mentioned specific organic silicon compound "h / (e + f + g + h)" with respect to the above-mentioned aromatic vinyl content (% by mass) of the aromatic vinyl-conjugated diene copolymer (hereinafter, also referred to as "aromatic vinyl content A"). The ratio of "x 100 (%) (hereinafter, also referred to as" aromatic vinyl content B ") (aromatic vinyl content B / aromatic vinyl content A) is 0 because the effect of the present invention is more excellent. It is preferably .5 to 1.5, more preferably 0.6 to 1.0, and even more preferably 0.7 to 0.9. For example, in the examples described later, the aromatic vinyl content A of Toughden E680 is 36% by mass, and the aromatic vinyl content B of the specific organosilicon compound is 28.2 (= 29 / (52 + 0 + 22 + 29) × 100. )%, So the aromatic vinyl content B / aromatic vinyl content A is 0.78.
Further, the above-mentioned "(f + g) / (e + f + g)" of the above-mentioned specific organosilicon compound with respect to the vinyl bond amount (%) (hereinafter, also referred to as "vinyl bond amount A") of the above-mentioned aromatic vinyl-conjugated diene copolymer. The ratio of × 100 (%) (hereinafter, also referred to as “vinyl bond amount B”) (vinyl bond amount B / vinyl bond amount A) is 0.1 to 1.0 because the effect of the present invention is more excellent. It is preferably 0.2 to 0.8, more preferably 0.4 to 0.6, and even more preferably 0.4 to 0.6. For example, in the examples described later, the vinyl bond amount A of Toughden E680 is 65%, and the vinyl bond amount B of the specific organosilicon compound is 29.7 (= 22 / (52 + 0 + 22) × 100)%. , The vinyl bond amount B / vinyl bond amount A is 0.46.

[Manufacturing method of specific organosilicon compound]
The method for producing the specific organosilicon compound is not particularly limited, but for the reason that the effect of the present invention is more excellent, the butadiene-styrene copolymer represented by the formula (II) and the formula (III) are represented as shown in the following scheme. A method for producing the organosilicon compound to be produced by hydrosilylation in the presence of a platinum compound-containing catalyst, preferably in the presence of a platinum compound-containing catalyst and a co-catalyst is preferable.

Definitions, specific examples and suitable embodiments of R ¹ , R ² , f, e, g, h and m in the above formulas (II) and (III) are described in R ¹ , R in the above formula (I), respectively. ² , f, e, g, h and m are the same.

The number average molecular weight (Mn) of the butadiene-styrene copolymer represented by the formula (II) is preferably 25,000 or less, and more preferably 10,000 or less, for the reason that the effect of the present invention is more excellent. preferable. The lower limit is not particularly limited, but is preferably 1,000 or more, and more preferably 5,000 or more, for the reason that the effect of the present invention is more excellent.

The butadiene-styrene copolymer represented by the formula (II) can be synthesized by a known method such as emulsion polymerization or solution polymerization using butadiene and styrene as raw material monomers, but can also be obtained as a commercially available product, for example. , Ricon100, Ricon181, and Ricon184 (all manufactured by Polymery) are on the market.

On the other hand, examples of the organosilicon compound represented by the formula (III) include trimethoxysilane, methyldimethoxysilane, dimethylmethoxysilane, triethoxysilane, methyldiethoxysilane, and dimethylethoxysilane. Of these, triethoxysilane is preferable because the effect of the present invention is more excellent.

The platinum compound-containing catalyst used in the hydrosilylation reaction is not particularly limited, and specific examples thereof include platinum chloride, an alcohol solution of platinum chloride, and platinum-1,3-divinyl-1,1. , 3,3-Tetramethyldisiloxane complex in toluene or xylene, tetraxtriphenylphosphine platinum, dichlorobistriphenylphosphine platinum, dichlorobis acetonitrile platinum, dichlorobisbenzonitrile platinum, dichlorocyclooctadiene platinum, etc., platinum-carbon , Platinum-alumina, platinum-silica and other supported catalysts.
From the viewpoint of selectivity during hydrosilylation, a 0-valent platinum complex is preferable, and a toluene or xylene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex is more preferable.
The amount of the platinum compound-containing catalyst used is not particularly limited, but from the viewpoint of reactivity, productivity, etc., 1 × of platinum atoms contained in 1 mol of the organosilicon compound represented by the formula (3). An amount of ^10-7 to 1 × 10 ⁻² mol is preferable, and an amount of 1 × ^10-7 to 1 × 10 ⁻³ mol is more preferable.

As the co-catalyst in the above reaction, it is preferable to use one or more selected from an ammonium salt of an inorganic acid, an acid amide compound and a carboxylic acid.
Specific examples of ammonium salts of inorganic acids include ammonium chloride, ammonium sulfate, ammonium ammonium sulfate, ammonium nitrate, monoammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium diaphosphate, ammonium carbonate, and hydrogen carbonate. Ammonium, ammonium sulfide, ammonium borate, ammonium borofluoride and the like can be mentioned. Among them, ammonium salts of inorganic acids having a pKa of 2 or more are preferable, and ammonium carbonate and ammonium hydrogencarbonate are preferable because the effect of the present invention is more excellent. Is more preferable.

Specific examples of the acid amide compound include formamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, acrylamide, malonamide, succinamide, maleamide, fumalamide, benzamide, phthalamide, palmitate amide, stearate amide and the like. Can be mentioned.

Specific examples of the carboxylic acid include acetic acid, propionic acid, butyric acid, methoxyacetic acid, pentanoic acid, caproic acid, heptonic acid, octanoic acid, lactic acid, glycolic acid and the like, and among these, acetic acid, acetic acid and lactic acid are preferable. , Acetic acid is more preferred.

The amount of the co-catalyst used is not particularly limited, but 1 × 10 ^-5 to 1 × 10 ⁻ per 1 mol of the organosilicon compound represented by the formula (III) from the viewpoint of reactivity, selectivity, cost and the like. ¹ mol is preferable, and 1 × 10 ^-4 to 5 × 10 ^-1 mol is more preferable.

Although the above reaction proceeds without a solvent, a solvent can also be used.
Specific examples of the solvent that can be used include hydrocarbon solvents such as pentane, hexane, cyclohexane, heptane, isooctane, benzene, toluene and xylene; ether solvents such as diethyl ether, tetrahydrofuran and dioxane; ethyl acetate, butyl acetate and the like. Ester-based solvents; aprotonic polar solvents such as N, N-dimethylformamide; chlorinated hydrocarbon-based solvents such as dichloromethane and chloroform, and the like, even if one of these solvents is used alone, 2 A mixture of seeds or more may be used.

The reaction temperature in the hydrosilylation reaction is not particularly limited, and is preferably 0 to 200 ° C. for the reason that the effect of the present invention is more excellent.
In order to obtain an appropriate reaction rate, the reaction is preferably carried out under heating, and from such a viewpoint, the reaction temperature is more preferably 40 to 110 ° C, and even more preferably 40 to 90 ° C.
The reaction time is also not particularly limited and is usually about 1 to 60 hours, but 1 to 30 hours is preferable and 1 to 20 hours is more preferable because the effect of the present invention is more excellent.

〔Content〕
In the composition of the present invention, the content of the specific organosilicon compound is 1 to 20% by mass with respect to the content of silica described above. Among them, 2 to 10% by mass is more preferable because the effect of the present invention is more excellent.

Further, in the composition of the present invention, the content of the specific organosilicon compound is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the above-mentioned diene-based rubber, for the reason that the effect of the present invention is more excellent. More preferably, it is 2 to 10 parts by mass.

Further, in the composition of the present invention, the content of the specific organic silicon compound is 1% by mass with respect to the content of the above-mentioned aromatic vinyl-conjugated diene copolymer rubber because the effect of the present invention is more excellent. The above is preferable, 2% by mass or more is more preferable, 5% by mass or more is further preferable, and 10% by mass or more is particularly preferable. The upper limit is not particularly limited, but is preferably 20% by mass or less for the reason that the effect of the present invention is more excellent.

[Contents of Specified Organosilicon Compound with respect to Specified Resin Content]
In the composition of the present invention, the content of the above-mentioned specific organosilicon compound with respect to the content of the above-mentioned specific resin is not particularly limited, but is preferably 1 to 50% by mass for the reason that the effect of the present invention is more excellent. It is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and even more preferably 15 to 20% by mass.

[Arbitrary ingredient]
The composition of the present invention may contain components (arbitrary components) other than the above-mentioned components, if necessary.
Examples of such a component include a filler other than silica (for example, carbon black), a resin other than the above-mentioned specific resin, a terpene resin (preferably an aromatic-modified terpene resin), a heat-expandable microcapsule, and zinc oxide. Generally used in rubber compositions such as (zinc flower), stearic acid, anti-aging agents, waxes, processing aids, oils, liquid polymers, thermosetting resins, vulcanizing agents (eg sulfur), vulcanization accelerators, etc. Examples include various additives used.

<Carbon black>
The composition of the present invention preferably contains carbon black because the effect of the present invention is more excellent.
The carbon black is not particularly limited, and for example, various grades such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, SRF and the like. Can be used.
The nitrogen adsorption specific surface area (N ₂ SA) of the carbon black is not particularly limited, but is preferably 50 to 200 m ² / g, preferably 70 to 150 m ² / g, for the reason that the effect of the present invention is more excellent. Is more preferable.
Here, the nitrogen adsorption specific surface area (N ₂ SA) is the amount of nitrogen adsorbed on the carbon black surface according to JIS K6217-2: 2001 "Part 2: How to obtain the specific surface area-Nitrogen adsorption method-Single point method". It is a measured value.

In the composition of the present invention, the content of carbon black is not particularly limited, but for the reason that the effect of the present invention is more excellent, it is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the above-mentioned diene-based rubber. More preferably, it is 2 to 10 parts by mass.

[Preparation method of rubber composition for tires]
The method for producing the composition of the present invention is not particularly limited, and as a specific example thereof, each of the above-mentioned components is kneaded using a known method or apparatus (for example, Banbury mixer, kneader, roll, etc.). The method etc. can be mentioned. When the composition of the present invention contains sulfur or a vulcanization accelerator, components other than sulfur and the vulcanization accelerator are first mixed at a high temperature (preferably 100 to 160 ° C.), cooled, and then sulfur or It is preferable to mix the vulcanization accelerator.
In addition, the composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[2] Pneumatic tire The pneumatic tire of the present invention is a pneumatic tire manufactured by using the composition of the present invention described above. Above all, it is preferable that the tire is a pneumatic tire in which the composition of the present invention is used (arranged) for a tire tread (cap tread).
FIG. 1 shows a schematic partial cross-sectional view of a pneumatic tire showing an example of an embodiment of the pneumatic tire of the present invention, but the pneumatic tire of the present invention is not limited to the embodiment shown in FIG.

In FIG. 1, reference numeral 1 represents a bead portion, reference numeral 2 represents a sidewall portion, and reference numeral 3 represents a tire tread portion.
Further, a carcass layer 4 in which a fiber cord is embedded is mounted between the pair of left and right bead portions 1, and the end portions of the carcass layer 4 are located around the bead core 5 and the bead filler 6 from the inside to the outside of the tire. It is folded back and rolled up.
Further, in the tire tread portion 3, the belt layer 7 is arranged on the outside of the carcass layer 4 over one circumference of the tire.
Further, in the bead portion 1, the rim cushion 8 is arranged at a portion in contact with the rim.
The tire tread portion 3 is formed by the composition of the present invention described above.

The pneumatic tire of the present invention can be manufactured, for example, according to a conventionally known method. Further, as the gas to be filled in the pneumatic tire, an inert gas such as nitrogen, argon or helium can be used in addition to normal air or air adjusted for oxygen partial pressure.

The pneumatic tire of the present invention is particularly suitable for competition wet tires.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

[Manufacturing of specific polysiloxane]
107.8 g (0.2 mol), γ-mercapto of bis (triethoxysilylpropyl) tetrasulfide (KBE-846 manufactured by Shin-Etsu Chemical Co., Ltd.) in a 2 L separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer. Contains 190.8 g (0.8 mol) of propyltriethoxysilane (KBE-803 manufactured by Shin-Etsu Chemical Co., Ltd.), 442.4 g (1.6 mol) of octyltriethoxysilane (KBE-3083 manufactured by Shin-Etsu Chemical Co., Ltd.), and 190.0 g of ethanol. Then, a mixed solution of 37.8 g (2.1 mol) of 0.5N hydrochloric acid and 75.6 g of ethanol was added dropwise at room temperature. Then, the mixture was stirred at 80 ° C. for 2 hours. Then, 17.0 g of a 5% KOH / EtOH solution was added dropwise, and the mixture was stirred at 80 ° C. for 2 hours. Then, it was concentrated under reduced pressure and filtered to obtain 480.1 g of polysiloxane as a brown transparent liquid. As a result of measurement by GPC, the average molecular weight was 840 and the average degree of polymerization was 4.0 (set degree of polymerization 4.0). Further, as a result of measuring the mercapto equivalent by the method of adding acetic acid / potassium iodide / potassium iodate-sodium thiosulfate solution titration method, it was 730 g / mol, and it was confirmed that the mercapto group content was as set. From the above, it is shown by the following average composition formula.
(-C ₃ H ₆ -S ₄ -C ₃ H _6- ) _0.071 (-C ₈ H ₁₇ ) _0.571 (-OC ₂ H ₅ ) _1.50 (-C ₃ H ₆ SH) _0.286 SiO _0.75
The obtained polysiloxane is designated as a specific polysiloxane.

[Manufacturing of Specified Organosilicon Compound]
Toluene 181 (manufactured by Cray Valley, number average molecular weight: 7,100, butadiene-styrene copolymer represented by the above formula (II)) in a 1 L separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer. , E = 52, (f + g) = 22, h = 29) 100 g, toluene 200 g, platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex toluene solution in formula (II). (3.1 × 10 ^-3 mol as platinum atom) and 0.2 g (1.5 × 10 ^-3 mol) of acetic acid were charged. 51 g (0.31 mol) of triethoxysilane was added dropwise thereto at an internal temperature of 75 to 85 ° C. over 2 hours, and then the mixture was stirred at 80 ° C. for 1 hour. The reaction rate of triethoxysilane analyzed by gas chromatography was 98%.
After the stirring was completed, the mixture was concentrated under reduced pressure and filtered to obtain a brown transparent liquid having a viscosity of 8,000 mPa · s and a number average molecular weight of 10,500. From the molecular weight and ¹ H-NMR spectrum, the liquid obtained was the above-mentioned specific organosilicon compound (in the above-mentioned formula (I), R ¹ = ethyl group, e = 52, f = 0, g = 22, h = 29, m = 3) was found.

[Preparation of rubber composition for tires]
The components shown in Table 1 below were blended in the proportions (parts by mass) shown in the same table. Specifically, it was mixed for 2 minutes with a Banbury mixer at 150 ° C. Next, using a roll, sulfur and a vulcanization accelerator were mixed to obtain a rubber composition for a tire.
In Table 1, the mass portion of SBR is the net mass portion of SBR excluding oil spread oil.

〔evaluation〕
The obtained rubber composition for tires was evaluated as follows.

<Sheet property>
Using two rolls, the obtained rubber composition for tires was made into a sheet. Then, the sheet property was evaluated based on the following criteria.
The results are shown in Table 1. Practically, it is preferably ◯.
◯: The rubber composition was attached to only one of the rolls, and the work such as turning back could be performed smoothly.
Δ: The rubber composition adhered not only to one roll but also to the other roll to some extent, and it was a little difficult to perform work such as turning back.
X: A large amount of rubber composition adhered not only to one roll but also to the other roll, and it was extremely difficult to perform operations such as turning back.

<Operability>
The obtained rubber composition for tires (unvulcanized) was press-vulcanized in a mold (15 cm × 15 cm × 0.2 cm) at 160 ° C. for 20 minutes to prepare a vulcanized rubber sheet. The obtained vulcanized rubber sheet was cut into a dumbbell shape (dumbbell shape No. 3) having a thickness of 2 mm and used as a test piece.
About the obtained test piece, 300% modulus (stress at the time of 300% elongation) [MPa] was measured according to JIS K6251: 2010.
The results are shown in Table 1. The results are expressed as an exponent with Comparative Example 1 as 100. The smaller the index, the better the operability. Practically, it is preferably 100 or less.

<Wet grip performance>
A vulcanized rubber sheet was prepared as described above.
Regarding the obtained vulcanized rubber sheet, according to JISK6394: 2007, using a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the stretch deformation strain rate is 10% ± 2%, the frequency is 20 Hz, and the temperature is 0 ° C. Tanδ (0 ° C.) was measured.
The results are shown in Table 1. The results are expressed as an exponent with Comparative Example 1 as 100. The larger the index, the better the wet grip performance. Practically, it is preferably 103 or more.

<Breaking elongation and breaking strength>
A vulcanized rubber sheet was prepared as described above. The obtained vulcanized rubber sheet was cut into a dumbbell shape (dumbbell shape No. 3) having a thickness of 2 mm and used as a test piece.
The obtained test pieces were measured for breaking elongation (= elongation at break) and breaking strength (= strength at breaking) under the conditions of a temperature of 20 ° C. and a tensile speed of 500 mm / min according to JIS K6251: 2010.
The results are shown in Table 1. The results are expressed as an exponent with Comparative Example 1 as 100. A larger index is preferable, and practically, it is preferably 105 or more.

The details of each component in Table 1 above are as follows.
Since the specific organosilicon compound is an organosilicon compound represented by the above-mentioned formula (I), it corresponds to the above-mentioned specific organosilicon compound. Further, since the specific resin is a resin having a softening point of 80 to 160 ° C., it corresponds to the above-mentioned specific resin. The Mn of SBR is 50,000 or more.
SBR: Toughden E680 (styrene-butadiene copolymer rubber (solution-polymerized styrene-butadiene rubber), aromatic vinyl content: 36% by mass, vinyl bond amount: 65%, Tg: -13 ° C., weight average molecular weight: 1.6 million , Oil-extended product (contains 37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR. Net SBR in SBR is 72.7% by mass, manufactured by Asahi Kasei Chemicals Co., Ltd.)
-Silica: Zeosil 1165MP (CTAB = 159m ² / g, manufactured by Rhodia)
-Carbon black: Seast 9 (N ₂ SA = 142m ² / g, manufactured by Tokai Carbon Co., Ltd.)
-Silane coupling agent 1: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Evonik Degussa)
-Silane coupling agent 2: Specific polysiloxane manufactured as described above-Specific organosilicon compound: Specific organosilicon compound manufactured as described above-Specific resin: FTR2140 (α-methylstyrene-styrene copolymer, softening point: 140) ℃, manufactured by Mitsui Chemicals, Inc.)
・ Zinc oxide: 3 types of zinc oxide (manufactured by Shodo Chemical Industry Co., Ltd.)
・ Stearic acid: Beaded stearic acid YR (manufactured by NOF CORPORATION)
-Anti-aging agent: Santoflex 6PPD (manufactured by Solutia Europe)
・ Oil: Extract No. 4 S (manufactured by Showa Shell Sekiyu Co., Ltd.)
・ Sulfur: Fine sulfur powder containing Jinhua Ink oil (manufactured by Tsurumi Chemical Industry Co., Ltd.)
・ Vulcanization accelerator 1: Vulcanization accelerator DPG (Noxeller D, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.)
-Vulcanization accelerator 2: Vulcanization accelerator CBS (Noxeller CZ-G, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.)

As can be seen from Table 1, Examples 1 to 3 containing a specific resin, a specific organosilicon compound, etc. in a specific ratio have excellent sheet properties, operability and wet grip properties, and high breaking elongation and breaking strength. Indicated. Among them, Examples 2 and 3 in which the silane coupling agent is a specific polysiloxane showed better operability and higher breaking elongation and breaking strength. Among them, Example 3 in which the content of the specific organosilicon compound is 10 parts by mass or more with respect to 100 parts by mass of the diene-based rubber has further excellent operability and wet grip performance, as well as higher breaking elongation and breaking strength. showed that.

On the other hand, Comparative Examples 1 and 6 containing no specific organic silicon compound, Comparative Example 2 containing a specific resin and a specific organic compound, but the content of the specific resin is less than 10 parts by mass with respect to 100 parts by mass of the diene rubber. Comparative Example 3, which contains a specific resin and a specific organic compound, but the content of the specific resin exceeds 60 parts by mass with respect to 100 parts by mass of the diene rubber, and the specific resin and the specific organic compound are contained, but the content of silica is diene. Comparative Example 4 which is less than 120 parts by mass with respect to the system rubber, and Comparative Example 5 which contains a specific resin and a specific organic compound but the content of the specific organic silicon compound exceeds 20% by mass with respect to the content of silica. Was insufficient in at least one of sheet property, operability, wet grip property, breaking elongation and breaking strength.

1 Bead part 2 Side wall part 3 Tire tread part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Rim cushion

Claims (3)

A diene-based rubber containing at least an aromatic vinyl-conjugated diene copolymer rubber, silica, a resin having a softening point of 80 to 160 ° C., a silane coupling agent, and an organosilicon compound represented by the following formula (I). And contains,
The silane coupling agent is a polysiloxane represented by the average composition formula of the following formula (1).
The silica content is 120 parts by mass or more with respect to 100 parts by mass of the diene rubber.
The content of the resin is 10 to 60 parts by mass with respect to 100 parts by mass of the diene rubber.
The content of the silane coupling agent is 2 to 20% by mass with respect to the content of the silica.
A rubber composition for a tire, wherein the content of the organosilicon compound is 1 to 20% by mass with respect to the content of the silica.
(A) _a (B) _b (C) _c (D) _d (R ¹ ) _e SiO _{(4-2a-b-c-d-e) / 2} (1)
In formula (1), A represents a divalent organic group containing a sulfide group. B represents a monovalent hydrocarbon group having 5 to 10 carbon atoms. C represents a hydrolyzable group. D represents an organic group containing a mercapto group. R ¹ represents a monovalent hydrocarbon group having 1 to 4 carbon atoms. a to e satisfy the relational expression of 0 ≦ a <1, 0 <b <1, 0 <c <3, 0 <d <1, 0 ≦ e <2, 0 <2a + b + c + d + e <4.

In the formula (I), R ¹ represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, and R ² is an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. Represents a group, f represents a number greater than or equal to 0, e, g and h represent numbers greater than 0 independently of each other, and m represents an integer of 1 to 3. However, the order of each repeating unit is arbitrary. The rubber composition for a tire according to claim 1, wherein the resin has a repeating unit derived from α-methylstyrene. A pneumatic tire using the rubber composition for a tire according to claim 1 or 2 .

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