JP2019052217A - Rubber composition for tire and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire rubber composition having excellent silica dispersibility and capable of ensuring excellent wear resistance while maintaining excellent wet grip performance and low rolling resistance when formed into a tire, and for the tire. Provided is a pneumatic tire using a rubber composition. A diene rubber, silica having a CTAB adsorption specific surface area of 210 to 300 m 2 /g, a hydrocarbon group of 3 to 30 carbon atoms, a piperazine ring, a morpholine ring, and a thiomorpholine ring are selected. A silica containing a heterocyclic compound having at least one kind of heterocycle (however, the above heterocyclic compound does not have a silicon atom) and an alkyltriethoxysilane having an alkyl group having 3 to 20 carbon atoms, and silica. Is from 80 to 150 parts by mass with respect to 100 parts by mass of the diene rubber, the content of the heterocyclic compound is from 0.5 to 20% by mass with respect to silica, and the content of the alkyltriethoxysilane is A rubber composition for a tire, which is 0.5 to 20 parts by mass with respect to a diene rubber. [Selection diagram] Figure 1

Description

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

Heretofore, it has been required to reduce the rolling resistance of a tire from the viewpoint of low fuel consumption when the vehicle is traveling. Further, from the viewpoint of safety, improvement in wet grip performance (braking performance on wet road surfaces) is required. On the other hand, there is known a method in which silica is blended with a rubber component constituting a tread portion of a tire to achieve both low rolling resistance and wet grip performance.
Furthermore, in recent years, a technology using silica having a large specific surface area has been known in response to the demand for higher performance of the tire.
However, since silica has a low affinity with the rubber component and the cohesion between the silicas is high, the silica does not disperse even if it is simply blended in the rubber component, and the effect of reducing rolling resistance and wet grip performance There has been a problem that the effect of improving the

  With respect to the above problems, a rubber composition for a tire, which contains a diene rubber, silica, a sulfur-containing silane coupling agent and an alkyltriethoxysilane, has been proposed (for example, Patent Document 1).

On the other hand, there is known a method of adding a hydrolyzable silane which functions as a coupling agent between a filler and a diene elastomer to a rubber composition.
For example, Patent Document 2 discloses a diene elastomer composition comprising a diene elastomer, a hydrolyzable silane, and a curing agent for the diene elastomer, wherein the hydrolyzable silane has a specific structure. A diene elastomeric composition is described which is a silane.

International Publication No. 2012/035998 Japanese Patent Publication No. 2015-502357

However, when a large amount of silica having a large specific surface area is blended with a rubber composition containing a diene rubber and a sulfur-containing silane coupling agent as in Patent Document 1 above, the effect by the silica blending is expected, but Silica tends to aggregate and dispersion of silica tends to be insufficient.
The present inventors also considered that there is room for improvement in the abrasion resistance, low rolling resistance and wet grip performance of the rubber obtained from such a rubber composition (Standard Example in Table 1).

Further, the inventors of the present invention prepared a rubber composition containing a hydrolyzable silane having a piperazine ring with reference to Patent Document 2 and evaluated the result. In such a composition, dispersion of silica is considered. In some cases, the wear resistance, the low rolling resistance, and the wet grip performance may be low (Comparative Example 5).
Therefore, the present invention provides a rubber composition for a tire capable of securing excellent wear resistance while maintaining excellent wet grip performance and low rolling resistance when the tire is excellent in silica dispersibility, and An object of the present invention is to provide a pneumatic tire using the above rubber composition for a tire.

As a result of intensive studies to solve the above problems, the present inventors have found that a heterocyclic compound having a specific structure is effective for the dispersibility of silica, and further, wet grip performance, low rolling resistance and wear resistance. I found that it was effective.
Furthermore, the present inventors have said that the above-mentioned heterocyclic compound and a predetermined alkyltriethoxysilane are compounded at a specific content with respect to the case where the CTAB adsorption specific surface area and the content of silica are within a predetermined range. It has been found that the problems can be solved, and the present invention has been achieved.
That is, this invention can solve the said subject by the following structures.

[1] with diene rubber,
Silica having a CTAB adsorption specific surface area of 210 to 300 m ² / g,
A heterocyclic compound having a hydrocarbon group of 3 to 30 carbon atoms and at least one hetero ring selected from the group consisting of piperazine ring, morpholine ring and thiomorpholine ring (however, the above-mentioned heterocyclic compound has a silicon atom) Not) and
And alkyltriethoxysilane having an alkyl group of 3 to 20 carbon atoms,
The content of the silica is 80 to 150 parts by mass with respect to 100 parts by mass of the diene rubber,
The content of the above heterocyclic compound is 0.5 to 20% by mass with respect to the above silica,
The rubber composition for tires, whose content of the said alkyl triethoxysilane is 0.5-20 mass parts with respect to the said diene rubber.
[2] The rubber composition for a tire according to the above [1], wherein the heterocyclic compound is a compound represented by the following formula (I).
In formula (I), X ₇ represents at least one selected from the group consisting of nitrogen atom, oxygen atom and sulfur atom,
Each of X ₃ , X ₄ , X ₅ and X ₆ independently represents a hydrogen atom or a hydrocarbon group.
When X ₇ is a nitrogen atom, n 3 is 1, and one or both of X ₁ and X ₂ are each independently a group of the formula (I-1):-(A ₁ ) _{n 1-1-} R _{1 Represents -1} ,
When only one of X ₁ and X ₂ represents the formula (I-1), the remaining groups are a hydrogen atom, a sulfone-based protecting group, a carbamate-based protecting group and a formula (I-3):-(R ₂ ) -O) represents at least one selected from the group consisting of _n2- H,
In formula (I-3), each R ₂ independently represents a divalent hydrocarbon group,
n2 represents 1 to 10;
When X ₇ is at least one selected from the group consisting of an oxygen atom and a sulfur atom, n 3 represents 0, and X ₁ represents a group of the formula (I-1):-(A ₁ ) _{n 1-1-} R _1- It represents _1.
In formula (I-1), A ₁ represents at least one member selected from the group consisting of a carbonyl group and formula (I-2): -R _1-2 (OH) -O-,
n1-1 represents 0 or 1 and
R _1-1 represents a hydrocarbon group having 3 to 30 carbon atoms,
In formula (I-2), R _1-2 represents a trivalent hydrocarbon group.
[3] The above heterocyclic compound is a compound represented by the above formula (I), X ₇ is a nitrogen atom, and n 3 is 1.
The rubber composition for a tire according to the above [2], wherein both X ₁ and X ₂ independently represent the above formula (I-1).
[4] The above heterocyclic compound is a compound represented by the above formula (I), X ₇ is a nitrogen atom, and n 3 is 1.
Only one of X ₁ and X ₂ represents the above formula (I-1),
The remaining groups, represents at least one hydrogen atom, sulfone protecting groups, carbamate protecting groups and formula (I-3) is selected from :-( R ₂ -O) group consisting of _n2 -H, [2 ] The rubber composition for tires as described in []. In formula (I-3), each R ₂ independently represents a divalent hydrocarbon group, and n ₂ represents 1 to 10.
[5] The rubber composition for a tire according to any one of the above [1] to [4], further comprising a silane coupling agent.
[6] The diene rubber contains a modified diene rubber,
The rubber composition for a tire according to any one of the above [1] to [5], wherein the content of the modified diene rubber exceeds 50% by mass in the total amount of the diene rubber.
[7] A pneumatic tire comprising the rubber composition for a tire according to any one of the above [1] to [6] in a cap tread.

The rubber composition for a tire according to the present invention is excellent in the dispersibility of silica, and when made into a tire, can maintain excellent wear resistance while maintaining excellent wet grip performance and low rolling resistance.
Moreover, according to the present invention, a pneumatic tire can be provided.

FIG. 1 is a schematic partial cross-sectional view of a tire representing an example of an embodiment of a pneumatic tire according to the present invention.

The present invention will be described in detail below.
In the present specification, (meth) acrylate represents acrylate or methacrylate, (meth) acryloyl represents acryloyl or methacryloyl, and (meth) acrylic represents acrylic or methacryl.
Moreover, the numerical range represented using "-" in this specification means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.
In the present specification, unless otherwise specified, each component is not particularly limited as to its production method. For example, conventionally known ones can be mentioned.
In the present specification, unless otherwise specified, the respective components can be used alone or in combination of two or more substances corresponding to the components. When the component contains two or more substances, the content of the component means the total content of the two or more substances.
In the present specification, it may be said that the effect of the present invention is more excellent that at least one of the dispersibility of silica, the wet grip performance, the low rolling resistance and the abrasion resistance is more excellent.

[Rubber composition for tire]
The rubber composition for a tire of the present invention (composition of the present invention) is
With diene rubber,
Silica having a CTAB adsorption specific surface area of 210 to 300 m ² / g,
A heterocyclic compound having a hydrocarbon group of 3 to 30 carbon atoms and at least one hetero ring selected from the group consisting of piperazine ring, morpholine ring and thiomorpholine ring (however, the above-mentioned heterocyclic compound has a silicon atom) Not) and
And alkyltriethoxysilane having an alkyl group of 3 to 20 carbon atoms,
The content of the silica is 80 to 150 parts by mass with respect to 100 parts by mass of the diene rubber,
The content of the above heterocyclic compound is 0.5 to 20% by mass with respect to the above silica,
It is a rubber composition for tires whose content of the above-mentioned alkyl triethoxysilane is 0.5-20 mass parts to the above-mentioned diene system rubber.

Since the composition of the present invention has such a constitution, it is considered that a desired effect can be obtained. Although the reason is not clear, it is presumed that it is as follows.
The heterocyclic compound contained in the composition of the present invention has a hydrocarbon group having 3 to 30 carbon atoms and at least one hetero ring selected from the group consisting of a piperazine ring, a morpholine ring and a thiomorpholine ring.

It is considered that the above-mentioned hydrocarbon group is easy to interact with the diene rubber since it has hydrophobicity, and the above-mentioned heterocycle is easy to interact with silica since it has hydrophilicity.
Further, the above-mentioned heterocyclic compound does not form a chemical bond of those interacting with a diene rubber in the above-mentioned hydrocarbon group, and the above-mentioned heterocyclic compound interacting with the above-mentioned heterocycle in the above-mentioned heterocycle has a silicon atom. It is considered that the above heterocyclic compound does not form a chemical bond with silica because it does not have one.
Thus, the above-mentioned heterocyclic compound having the above-mentioned hydrocarbon group as a hydrophobic part and the above-mentioned heterocycle as a hydrophilic part functions like a surfactant in a composition containing a diene rubber and silica. The present inventors speculate that the dispersibility of silica in a diene rubber is enhanced.

Furthermore, as described above, the wet grip performance, low rolling resistance and abrasion resistance are superior when the composition of the present invention is made into a tire by increasing the dispersibility of silica in the diene rubber by the above-mentioned heterocyclic compound. Is estimated to be obtained.
Hereinafter, each component contained in the composition of this invention is explained in full detail.

<< Diene-based rubber >>
The composition of the present invention comprises a diene rubber.

The diene rubber is not particularly limited. For example, natural rubber (NR); aromatic vinyl-conjugated diene copolymer rubber such as styrene butadiene rubber (SBR), styrene isoprene copolymer rubber; isoprene rubber (IR), butadiene rubber, acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR) and the like.
Among these, at least one selected from the group consisting of aromatic vinyl-conjugated diene copolymer rubber and butadiene rubber is preferable, and at least one selected from the group consisting of SBR and butadiene rubber is more preferable.

(Modified diene rubber)
The diene rubber can include a modified diene rubber. The modified diene rubber can have a modifying group. The modifying group is preferably a group capable of interacting with or binding to silica. As the modifying group, for example, hydroxy group, carboxy group, amino group, imino group, thiol group, epoxy group, polysiloxane group such as polyorganosiloxane group, hydrocarbyloxysilane group such as alkoxysilyl group, silanol group, etc. A combination is mentioned.
Examples of the main chain of the modified diene rubber include the same as the above-mentioned diene rubber.
The modifying group and the main chain (the diene rubber) can be bonded directly or via an organic group. The organic group is not particularly limited.

When the diene rubber contains a modified diene rubber, the content of the modified diene rubber is more than 50% by mass in the total amount of the diene rubber from the viewpoint of being excellent due to the effect of the present invention (in particular, the wet grip performance). It is preferable that 70-80 mass% is more preferable.
Further, when the diene rubber contains a modified diene rubber, the content of the modified diene rubber can be 90% by mass or less in the total amount of the diene rubber.
When the diene rubber contains a modified diene rubber and a non-modified diene rubber (unmodified diene rubber), examples of the combination include a combination of modified SBR and unmodified BR.

The weight average molecular weight of the diene rubber can be a value exceeding 20,000. The weight average molecular weight of the diene rubber can be 2,000,000 or less.
The weight average molecular weight of the diene rubber is a standard polystyrene equivalent value based on the value measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

(Average glass transition temperature)
In the present invention, the average glass transition temperature (average Tg) of the diene rubber is not particularly limited.
The above average glass transition temperature is preferably −50 ° C. or more from the viewpoint of being excellent by the effect of the present invention (in particular, the wet grip performance).
The average glass transition temperature can be -20 ° C or less.
The average Tg of a diene rubber is obtained by multiplying the glass transition temperature (Tg) of each diene rubber by the mass% of each diene rubber with respect to the entire diene rubber, and adding them together.
When one type of diene-based rubber is used as the diene-based rubber, the average glass transition temperature of the diene-based rubber is the glass transition temperature of the one type of diene-based rubber.
The glass transition temperature of each diene rubber is measured at a temperature rising rate of 20 ° C./min using a differential scanning calorimeter (DSC), and calculated by the midpoint method.

<< Silica >>
The silica contained in the composition of the present invention is not particularly limited. For example, conventionally known silicas that are blended in rubber compositions for applications such as tires can be used.
Examples of the silica include wet silica, dry silica, fumed silica, diatomaceous earth and the like.

<CTAB adsorption specific surface area of silica>
In the present invention, the CTAB adsorption specific surface area of the above silica is 210 to 300 m ² / g.
The CTAB adsorption specific surface area of the above-mentioned silica is preferably 210 to 280 m ² / g, and more preferably 210 to 270 m ² / g, from the viewpoint of being excellent by the effect of the present invention (in particular, wet grip performance).
Here, the CTAB adsorption specific surface area is a substitute property of the surface area where silica can be utilized for adsorption with a silane coupling agent, and the amount of CTAB (cetyltrimethylammonium bromide) adsorbed on the silica surface is JIS K 6217-3: 2001 “No. It is a value measured according to “3 parts: determination method of specific surface area—CTAB adsorption method”.

<< Silica content >>
In the present invention, the content of the silica is 80 to 150 parts by mass with respect to 100 parts by mass of the diene rubber.
The content of the silica is preferably 80 to 120 parts by mass, and 80 to 110 parts by mass with respect to 100 parts by mass of the diene rubber, from the viewpoint of being excellent by the effect of the present invention (in particular, wet grip performance). It is more preferable that
In the present invention, the content of the silica can be less than 150 parts by mass with respect to 100 parts by mass of the diene rubber.

<< Heterocyclic compounds >>
The heterocyclic compound contained in the composition of the present invention is a compound having a hydrocarbon group having 3 to 30 carbon atoms and at least one heterocyclic ring selected from the group consisting of piperazine ring, morpholine ring and thiomorpholine ring. It is. In the present invention, the above heterocyclic compound does not have a silicon atom.
The said C3-C30 hydrocarbon group can function as a hydrophobic part.
In addition, the said heterocyclic compound can be taken as what does not have an enamine structure (N-C = C).

<C3-30 hydrocarbon group>
Examples of the C3-C30 hydrocarbon group include aliphatic hydrocarbon groups (including linear, branched and cyclic), aromatic hydrocarbon groups, and combinations thereof.
Among them, aliphatic hydrocarbon groups are preferable and saturated aliphatic hydrocarbon groups are more preferable, from the viewpoint of being excellent in dispersibility of silica and excellent in processability.

  The carbon number of the hydrocarbon group having 3 to 30 carbon atoms is preferably 8 to 22 and more preferably 8 to 18 from the viewpoint of being excellent in dispersibility of silica and excellent in processability.

A C3-C30 hydrocarbon group is mentioned as one of the preferable aspects comprised only with a carbon atom and a hydrogen atom.
The C3-C30 hydrocarbon group is mentioned as one of the aspects preferable to be monovalent.
One molecule of the heterocyclic compound may have one or more hydrocarbon groups each having 3 to 30 carbon atoms, and one molecule is preferably mentioned as one of two or more.

<Heterocycle>
In the present invention, the heterocyclic compound has at least one hetero ring selected from the group consisting of a piperazine ring, a morpholine ring and a thiomorpholine ring.
The molecule of the above-mentioned heterocyclic compound may have one or more of the above-mentioned heterocycle, and it is mentioned as one of the preferred embodiments that it has one.
The hetero ring is preferably a piperazine ring or a morpholine ring, more preferably a piperazine ring, from the viewpoint of being excellent in dispersibility of the silica and excellent in processability.

(Piperazine ring)
The piperazine ring means a backbone of piperazine. The heterocyclic compound which has a piperazine ring as a heterocyclic ring may be hereafter called "a piperazine compound." In the present invention, the piperazine ring does not contain a triethylenediamine skeleton (diazabicyclooctane skeleton).
(Morpholine ring)
The morpholine ring means the morpholine backbone. The heterocyclic compound having a morpholine ring as the heterocyclic ring may be hereinafter referred to as "morpholine compound".
(Thiomorpholine ring)
The thiomorpholine ring means a thiomorpholine skeleton. The heterocycle compound which has a thiomorpholine ring as a heterocycle may be called the following "thiomorpholine compound."

(Coupling of a C3-C30 Hydrocarbon Group with a Heterocycle)
The hydrocarbon group having 3 to 30 carbon atoms can be bonded to the nitrogen atom or carbon atom of the heterocycle of the heterocycle compound directly or through an organic group.
The C3-C30 hydrocarbon group is mentioned as one of the preferable aspects couple | bonded with the nitrogen atom of the heterocyclic ring which a heterocyclic compound has directly or via an organic group.
In the heterocyclic compound, when the hetero ring is a morpholine ring, a hydrocarbon group having 3 to 30 carbon atoms can be bonded directly or via an organic group to the nitrogen atom or carbon atom in the morpholine ring . The same applies to the case where the above heterocycle is a thiomorpholine ring.

The organic group is not particularly limited. For example, a hydrocarbon group having an oxygen atom can be mentioned. As a hydrocarbon group, the same thing as the above is mentioned, for example.
The oxygen atom may form, for example, a carbonyl group or a hydroxy group.
When the organic group is a hydrocarbon group having an oxygen atom at the end, the oxygen atom may be bonded to a hydrocarbon group having 3 to 30 carbon atoms to form an ether bond. The hydrocarbon group having an oxygen atom may further have a hydroxy group.

The piperazine compound can further have a hydrocarbon group having 3 to 30 carbon atoms and a substituent other than a piperazine ring. Examples of the substituent, for example, sulfone protecting group, carbamate protecting groups and formula (I-3) at least one can be cited selected from :-( R ₂ -O) group consisting of _n2 -H.
When the piperazine compound further has the above-mentioned substituent, the above-mentioned substituent can be bonded to the nitrogen atom of the piperazine ring which the piperazine compound has.

  In the piperazine compound, one hydrocarbon group having 3 to 30 carbon atoms is bonded to one of two nitrogen atoms of the piperazine ring, and the remaining nitrogen atom of the piperazine ring is substituted with a hydrogen atom or the above-mentioned Groups can be attached.

(Sulfone-based protecting group)
Examples of the sulfone-based protecting group include a methanesulfonyl group, a tosyl group and a nosyl group.

(Carbamate protecting group)
Examples of the carbamate protecting group include a tert-butoxycarbonyl group, an allyloxycarbonyl group, a benzyloxycarbonyl group and a 9-fluorenylmethyloxycarbonyl group.

(Formula (I-3))
In the formula _{(I-3) :-( R 2} -O) n2 -H, R 2 each independently represents a divalent hydrocarbon group.
In Formula (I-3), the carbon number of the divalent hydrocarbon group is preferably 2 to 3.
The divalent hydrocarbon group is preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched, cyclic or any combination thereof.
n2 represents 1 to 10, preferably 1 to 5.

The heterocyclic compound is preferably a compound represented by the following formula (I) from the viewpoint of being excellent in dispersibility of silica and excellent in processability.
In formula (I), X ₇ represents at least one selected from the group consisting of nitrogen atom, oxygen atom and sulfur atom,
Each of X ₃ , X ₄ , X ₅ and X ₆ independently represents a hydrogen atom or a hydrocarbon group.
When X ₇ is a nitrogen atom, n 3 is 1, and one or both of X ₁ and X ₂ are each independently a group of the formula (I-1):-(A ₁ ) _{n 1-1-} R _{1 Represents -1} ,
When only one of X ₁ and X ₂ represents the formula (I-1), the remaining groups are a hydrogen atom, a sulfone-based protecting group, a carbamate-based protecting group and a formula (I-3):-(R ₂ ) -O) represents at least one selected from the group consisting of _n2- H,
In formula (I-3), each R ₂ independently represents a divalent hydrocarbon group,
n2 represents 1 to 10;
When X ₇ is at least one selected from the group consisting of an oxygen atom and a sulfur atom, n 3 represents 0, and X ₁ represents a group of the formula (I-1):-(A ₁ ) _{n 1-1-} R _1- It represents _1.
In formula (I-1), A ₁ represents at least one member selected from the group consisting of a carbonyl group and formula (I-2): -R _1-2 (OH) -O-,
n1-1 represents 0 or 1 and
R _1-1 represents a hydrocarbon group having 3 to 30 carbon atoms,
In formula (I-2), R _1-2 represents a trivalent hydrocarbon group.

In formula (I), one or both of X ₁ and X ₂ each independently represent formula (I-1):-(A ₁ ) _n1-1 -R _1-1 .

(Formula (I-1))
In the formula (I-1):-(A ₁ ) _n1-1 -R _1-1 , A ₁ is a group _consisting of a carbonyl group and the formula (I-2): -R _1-2 (OH) -O- Represents at least one selected from
n1-1 represents 0 or 1;
R _1-1 represents a hydrocarbon group having 3 to 30 carbon atoms. The C3-C30 hydrocarbon group is the same as the above.

(Formula (I-2))
In Formula (I-2): -R _1-2 (OH) -O-, R _1-2 represents a trivalent hydrocarbon group.
The carbon number of the trivalent hydrocarbon group is preferably 3 to 30.
The trivalent hydrocarbon group is preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched, cyclic or any combination thereof.

In formula (I-2), the above-mentioned hydroxy group may be bonded to any carbon atom constituting R _1-2 .
In formula (I-1):-(A ₁ ) _n1-1 -R _1-1 , n1-1 is 1 and A ₁ is a group of formula (I-2): -R _1-2 (OH) -O When it _is- , R _1-2 in the formula (I-2) is bonded to the nitrogen atom of the heterocycle, and the above oxygen atom (-O-) in the formula (I-2) is bonded to R _1-1 , R _1-2 (trivalent hydrocarbon group) has 3 to 30 carbon atoms, and R _1-2 (trivalent hydrocarbon) between the oxygen atom (-O-) and the nitrogen atom of the heterocycle It is mentioned as one of the preferred embodiments that three or more carbon atoms among the carbon atoms possessed by the group) are arranged side by side.

_{(X 3, X 4, X} 5 and X ₆₎
In formula (I), X ₃ , X ₄ , X ₅ and X ₆ each independently represent a hydrogen atom or a hydrocarbon group.
The above-mentioned hydrocarbon group is not particularly limited. The hydrocarbon group may be a hydrocarbon group having 3 to 30 carbon atoms, or may be another hydrocarbon group.
X ₃ , X ₄ , X ₅ and X ₆ are mentioned as one of the preferred embodiments as a hydrogen atom.

In the formula (I), when X ₇ is a nitrogen atom, n 3 is 1 and only one of X ₁ and X ₂ represents the above formula (I-1), the remaining group is a hydrogen atom, sulfone protecting groups, carbamate protecting groups and formula _{(I-3) :-( R 2} -O) may represent at least one selected from the group consisting of _n2 -H.
That is, when X ₁ represents the above formula (I-1), X ₂ is a hydrogen atom, a sulfonic-based protective group, carbamate protecting groups and formula _{(I-3) :-( R 2} -O) n2 -H And at least one selected from the group consisting of
When X ₂ represents the above formula (I-1), X ₁ is a hydrogen atom, a sulfone-based protecting group, a carbamate-based protecting group and a formula (I-3):-(R ₂ -O) _n2 -H And at least one selected from the group consisting of The sulfone protecting group, the carbamate protecting group and the formula (I-3) are as defined above.

(When the heterocyclic compound is a compound represented by formula (I), X ₇ is a nitrogen atom and n 3 is 1)
The heterocyclic compound represented by the formula (I), wherein X ₇ is a nitrogen atom and n 3 is 1 is represented by the following formula (II).

In Formula (II), one or both of X ₁ and X ₂ each independently represent Formula (I-1):-(A ₁ ) _n1-1 -R _1-1 .

(Formula (I-1))
In the formula (I-1):-(A ₁ ) _n1-1 -R _1-1 , A ₁ is a group _consisting of a carbonyl group and the formula (I-2): -R _1-2 (OH) -O- Represents at least one selected from
n1-1 represents 0 or 1;
R _1-1 represents a hydrocarbon group having 3 to 30 carbon atoms. The C3-C30 hydrocarbon group is the same as the above.

(Formula (I-2))
In Formula (I-2): -R _1-2 (OH) -O-, R _1-2 represents a trivalent hydrocarbon group.
The carbon number of the trivalent hydrocarbon group is preferably 3 to 30.
The trivalent hydrocarbon group is preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched, cyclic or any combination thereof.

In formula (I-2), the above-mentioned hydroxy group may be bonded to any carbon atom constituting R _1-2 .
In formula (I-1):-(A ₁ ) _n1-1 -R _1-1 , n1-1 is 1 and A ₁ is a group of formula (I-2): -R _1-2 (OH) -O When it is-, R _1-2 in the formula (I-2) is bonded to the nitrogen atom of the piperazine ring, and the above oxygen atom (-O-) in the formula (I-2) is bonded to R _1-1 , R _1-2 (trivalent hydrocarbon group) has 3 to 30 carbon atoms, and R _1-2 (trivalent hydrocarbon) between the oxygen atom (-O-) and the nitrogen atom of the piperazine ring It is mentioned as one of the preferred embodiments that three or more carbon atoms among the carbon atoms possessed by the group) are arranged side by side.

_{(X 3, X 4, X} 5 and X ₆₎
In formula (II), X ₃ , X ₄ , X ₅ and X ₆ each independently represent a hydrogen atom or a hydrocarbon group.
The above-mentioned hydrocarbon group is not particularly limited. The hydrocarbon group may be a hydrocarbon group having 3 to 30 carbon atoms, or may be another hydrocarbon group.
X ₃ , X ₄ , X ₅ and X ₆ are mentioned as one of the preferred embodiments as a hydrogen atom.

When only one of X ₁ and X ₂ in the formula (II) represents the above-mentioned formula (I-1), the remaining groups are a hydrogen atom, a sulfone-based protecting group, a carbamate-based protecting group, and 3) :-( R ₂ -O) may represent at least one selected from the group consisting of _n2 -H.
That is, when X ₁ represents the above formula (I-1), X ₂ is a hydrogen atom, a sulfonic-based protective group, carbamate protecting groups and formula _{(I-3) :-( R 2} -O) n2 -H And at least one selected from the group consisting of
When X ₂ represents the above formula (I-1), X ₁ is a hydrogen atom, a sulfone-based protecting group, a carbamate-based protecting group and a formula (I-3):-(R ₂ -O) _n2 -H And at least one selected from the group consisting of The sulfone protecting group, the carbamate protecting group and the formula (I-3) are as defined above.

As a specific aspect of a piperazine compound, the following aspect 1 or 2 is mentioned, for example.
(Aspect 1 of a piperazine compound)
Aspect 1 of the piperazine compound is represented by formula (II):
It is a compound in which both of X ₁ and X ₂ each independently represent the above formula (I-1).
In the above embodiment _{1, X 3, X 4,} X 5 and X ₆ is preferably a hydrogen atom.

  As a specific example of the said aspect 1, the piperazine compounds 3, 5 and 8 represented by a following formula are mentioned, for example.

Piperazine compound 3

Piperazine compound 5

Piperazine compounds 8 (-C ₁₂ H ₂₅ R each independently or represents -C ₁₃ H _27.)
Incidentally, piperazine compound 8, compound both R is -C ₁₂ H _25, compounds both R is -C ₁₃ H ₂₇ and one of R a is -C ₁₂ H ₂₅ remaining R is -C _It may be a mixture of at least two selected from the group consisting of compounds which are ₁₃ H ₂₇ .

(Aspect 2 of a piperazine compound)
Aspect 2 of the piperazine compound is represented by formula (II):
Only one of X ₁ and X ₂ represents formula (I-1),
The remaining groups, being a compound represents at least one selected from a hydrogen atom, a sulfonic-based protective group, carbamate protecting group and the formula _{(I-3) :-( R 2} -O) group consisting of _n2 -H .
In the above embodiment 2, X ₃ , X ₄ , X ₅ and X ₆ are preferably hydrogen atoms.

  As a specific example of the said aspect 2, the piperazine compound 1, 2, 4, 6 and 7 represented by a following formula is mentioned, for example.

Piperazine compound 1

Piperazine compound 2 (in the following structural formula, n is 1 to 10, preferably 1 to 5.)

Piperazine compound 4

Piperazine compound 6

Piperazine compounds 7 (R is -C ₁₂ H _25, or, -C ₁₃ represents a H _27. Piperazine compound 7, piperazine compounds piperazine compounds wherein R is -C ₁₂ H ₂₅ and R is -C ₁₃ H ₂₇ It may be a mixture of

(When the heterocyclic compound is a compound represented by formula (I), X ₇ is an oxygen atom or a sulfur atom, and n 3 is 0)
The heterocyclic compound represented by the formula (I), wherein X ₇ is an oxygen atom or a sulfur atom and n 3 is 0 is represented by the following formula (III).
In the formula (III), X ₁ is the same as the formula (I-1) of the above formula (I):-(A ₁ ) _{n 1-1-} R _1-1 and X ₃ , X ₄ , X ₅ and X ₆ is the same respectively X _3, X _4, X ₅ and X ₆ in the formula (I), X ₈ is at least one selected from the group consisting of oxygen and sulfur atoms.

  Examples of the compound represented by the formula (III) include morpholine compounds 1 to 4 represented by the following formula.

(Morpholine compound 1)

(Morpholine compound 2)

(Morpholine compound 3)

(Morpholine compound 4)
In morpholine compound 4 R is -C ₁₂ H _25, or represents -C ₁₃ H _27. Morpholine compounds 4 may be a mixture of morpholine compounds morpholine compound R is -C ₁₂ H ₂₅ and R is -C ₁₃ H _27.

The heterocyclic compound is not particularly limited as to its method of preparation. For example, conventionally known ones can be mentioned.
Specifically, for example, at least one selected from the group consisting of piperazine which may have a substituent, morpholine and thiomorpholine, a halogen atom (chlorine, bromine, iodine etc.), an acid halogen group (acid chloride group And the hydrocarbon compound having 3 to 30 carbon atoms having at least one selected from the group consisting of acid bromide group, acid iodide group etc. and glycidyl oxy group, if necessary, in a solvent Can be obtained by The substituents are as described above. The C3-C30 hydrocarbon group which the said hydrocarbon compound has is the same as that of the above.
Further, as described above piperazine compound 2, as a method for producing a piperazine compound where further having the above formula _{(I-3) :-( R 2} -O) n2 -H, for example, hydroxy as piperazine compounds 1 There may be mentioned a method of reacting a piperazine compound having a group and an alkylene oxide in the presence of a metal alkoxide.

<< Heterocyclic Compound Content >>
In the present invention, the content of the heterocyclic compound is 0.5 to 20% by mass with respect to the content of the silica.
The content of the heterocyclic compound is preferably 1 to 15% by mass, relative to the content of the silica, from the viewpoint of being excellent by the effect of the present invention (particularly abrasion resistance) and excellent in processability. % By mass is more preferred.

<< Alkyl triethoxysilane >>
The composition of the present invention contains an alkyltriethoxysilane having an alkyl group of 3 to 20 carbon atoms.
The alkyl group contained in the above alkyltrialkoxysilane may be linear, branched and cyclic, and any combination thereof. The alkyl group is preferably linear.
The number of carbon atoms of the alkyl group is preferably 7 to 10 from the viewpoint of being more excellent due to the effects of the present invention (in particular, the dispersibility of silica).

  Examples of the alkyl group include propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl and dodecyl groups, with octyl and nonyl groups being more preferable .

<< Content of alkyltriethoxysilane >>
In the present invention, the content of the alkyltriethoxysilane is 0.5 to 20% by mass with respect to the silica.
The content of the alkyltriethoxysilane is preferably 3 to 15 parts by mass, and more preferably 5 to 10 parts by mass, with respect to the diene rubber, from the viewpoint of being excellent due to the effects of the present invention (particularly abrasion resistance). .

  The mass ratio of the above heterocyclic compound to the above alkyltriethoxysilane (heterocyclic compound / alkyltriethoxysilane) is preferably 0.1 to 5 from the viewpoint of being excellent by the effect of the present invention (in particular, abrasion resistance), 0.5-2 are more preferable.

(Silane coupling agent)
The composition of the present invention may further contain a silane coupling agent.
The silane coupling agent is not particularly limited. The silane coupling agent can have a hydrolyzable 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. Among them, an alkoxy group is preferable. When the hydrolyzable group is an alkoxy group, the carbon number of the alkoxy group is preferably 1 to 16, and more preferably 1 to 4. As a C1-C4 alkoxy group, a methoxy group, an ethoxy group, a propoxy group etc. are mentioned, for example.

The silane coupling agent can have, for example, a group having a sulfur atom in addition to the above hydrolyzable group. The sulfur atom can constitute, for example, a sulfide group (including a monosulfide group and a polysulfide group), a mercapto group and a carbonylthio group.
Examples of the silane coupling agent include a sulfur-containing silane coupling agent and a silane coupling agent having a polysiloxane skeleton.
The above-mentioned polysiloxane skeleton means a polymer having a plurality of repeating units of-(Si-O)-. The polysiloxane skeleton can be any of linear, branched, and three-dimensional structures, or a combination thereof.
The silane coupling agent may further have a polysiloxane skeleton or may not have a polysiloxane skeleton.

As a silane coupling agent, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxy) Silylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) Disulfide-like polysulfide silanes;
A silane coupling agent represented by the following formula (a);
A silane coupling agent represented by the following formula (b);
It is represented by the following formula (2) such as 3- [ethoxybis (3,6,9,12,15-pentaoxaoctacosan-1-yloxy) silyl] -1-propanethiol (Si363 manufactured by Evonik Degussa). And mercapto group-containing silane coupling agents such as γ-mercaptopropylmethyldimethoxysilane and γ-mercaptopropyltrimethoxysilane.

  Among them, polysulfide silane is preferable from the viewpoint of being excellent by the effect of the present invention.

-Silane coupling agent represented by Formula (a) Formula (a) is (C _L H 2 _{L + 1} O) ₃ -Si- (CH ₂ ) _m -S-C (= O)-(C _n H) _{2n + 1} ).
In formula (a), L is 1 to 3, m is 1 to 3, and n is 1 to 15.
C _L H _{2L + 1} may be linear or branched.
(C _n H _{2n + 1} ) may be linear, branched or cyclic, or a combination thereof.

  As a silane coupling agent represented by Formula (a), 3-octanoylthio 1-propyl triethoxysilane is mentioned, for example.

_-Silane coupling agent represented by Formula (b) Formula (b) is (A) _a (B) _b (C) _c (D) _d (R ¹ ) _e SiO _{(4-2a-bcde) / 2} It is.
Formula (b) is an average composition formula.

In formula (b), A represents a divalent organic group containing a sulfide group. B represents a C5-C10 monovalent hydrocarbon group. 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 0 ≦ a <1, 0 <b <1, 0 <c <3, 0 ≦ d <1, 0 ≦ e <2, and satisfy the relational expression of 0 <2a + b + c + d + e <4.
However, the case where a and d are 0 simultaneously is excluded.

  The silane coupling agent represented by the said Formula (b) is mentioned as one of the aspects with preferable having a polysiloxane structure.

(A)
In the above formula (b), A represents a divalent organic group containing a sulfide group (hereinafter also referred to as a sulfide group-containing organic group). The organic group can be, for example, a hydrocarbon group which may have a hetero atom such as an oxygen atom, a nitrogen atom or a sulfur atom.
Among them, a group represented by the following formula (4) is preferable.
^* -(CH ₂ ) _n- S _x- (CH ₂ ) _n- ^* (4)
In said formula (4), n represents the integer of 1-10, and it is preferable that it is an integer of 2-4 especially.
In said Formula (4), x represents the integer of 1-6, and it is preferable that it is an integer of 2-4 especially.
In the above formula (4), * indicates a bonding position.
Specific examples of the group represented by the formula (4), 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 - * , and the like.

(B)
In said Formula (b), B represents a C5-C10 monovalent hydrocarbon group, As a specific example, a hexyl group, an octyl group, a decyl group etc. are mentioned, for example. B can protect a mercapto group.
B is preferably a monovalent hydrocarbon group having 8 to 10 carbon atoms from the viewpoint of being excellent by the effect of the present invention (in particular, the dispersibility of silica) and excellent in processability.

(C)
In the above formula (b), C represents a hydrolyzable group, and specific examples thereof include an alkoxy group, a phenoxy group, a carboxyl group, an alkenyloxy group and the like. Among them, a group represented by the following formula (5) is preferable.
^* -OR ² (5)

In the above formula (5), 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 7 to 10 carbon atoms (arylalkyl group) or an alkenyl group having 2 to 10 carbon atoms Represents Among them, R ² is preferably an alkyl group having 1 to 5 carbon atoms.

As a specific example of the said C1-C20 alkyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, an octadecyl group etc. are mentioned, for example.
As a specific example of said C6-C10 aryl group, a phenyl group, a tolyl group, etc. are mentioned, for example.
As a specific example of the said C7-C10 aralkyl group, a benzyl group, a phenylethyl group, etc. are mentioned, for example.
As a specific example of the said C2-C10 alkenyl group, a vinyl group, a propenyl group, a pentenyl group etc. are mentioned, for example.
In the above formula (5), * indicates a bonding position.

(D)
In the above formula (b), D represents an organic group containing a mercapto group. Among them, a group represented by the following formula (6) is preferable.
^* -(CH ₂ ) _m- SH (6)

In said formula (6), m represents the integer of 1-10. Among these, m is preferably an integer of 1 to 5.
In the above formula (6), * indicates a bonding position.

Specific examples of the group represented by the above formula (6) include ^* -CH ₂ SH, ^* -C ₂ H ₄ SH, ^* -C ₃ H ₆ SH, ^* -C ₄ H ₈ SH, ^* -C ₅ H ₁₀ SH, ^* -C ₆ H ₁₂ SH, ^* -C ₇ H ₁₄ SH, ^* -C ₈ H ₁₆ SH, ^* -C ₉ H ₁₈ SH, ^* -C ₁₀ H ₂₀ SH.

(R ¹ )
In the above formula (b), R ¹ represents a monovalent hydrocarbon group having 1 to 4 carbon atoms. For example, a methyl group, an ethyl group, a propyl group and a butyl group can be mentioned.

(A to e)
In the above formula (b), a to e satisfy 0 ≦ a <1, 0 <b <1, 0 <c <3, 0 ≦ d <1, and 0 ≦ e <2, 0 <2a + b + c + d + e < Satisfy the relational expression of 4.

  It is preferable that a is larger than 0 (0 <a) from the viewpoint that the silane coupling agent represented by the formula (b) is excellent due to the effect of the present invention (in particular, the dispersibility of silica) and excellent in processability. It is more preferable that 0 <a ≦ 0.50.

  In the above formula (b), b is preferably 0.10 ≦ b ≦ 0.89 from the viewpoint of being excellent by the effect of the present invention (in particular, the dispersibility of silica) and excellent in processability.

  In the above formula (b), c is preferably 1.2 ≦ c ≦ 2.0 from the viewpoint of being excellent by the effect of the present invention (in particular, the dispersibility of silica) and excellent in processability.

  In the above formula (b), d is preferably 0.1 ≦ d ≦ 0.8 from the viewpoint of being excellent by the effect of the present invention (in particular, the dispersibility of silica) and excellent in processability.

  In the above formula (b), 0 <2a + b + c + d + e ≦ 3 is preferable from the viewpoint of being excellent by the effect of the present invention (in particular, the dispersibility of silica) and excellent in processability.

  The silane coupling agent represented by the formula (b) is excellent in the effect of the present invention (in particular, the dispersibility of the silica), and from the viewpoint of excellent processability, in the above formula (b), A is the above formula (4) It is preferable that C is a group represented by said Formula (5), D is a group represented by said Formula (6), A is a group represented by said Formula (4), C is a group represented by the above formula (5), D is a group represented by the above formula (6), and B is a monovalent hydrocarbon group having 8 to 10 carbon atoms It is more preferable that

  The weight average molecular weight of the silane coupling agent represented by the formula (b) is preferably 500 to 2300 from the viewpoint of being excellent by the effect of the present invention (particularly the dispersibility of silica) and excellent in processability, 600 It is more preferable that it is -1500. The molecular weight of the silane coupling agent represented by Formula (b) is a weight average molecular weight calculated in terms of polystyrene by gel permeation chromatography (GPC) using toluene as a solvent.

  The mercapto equivalent of the silane coupling agent represented by the formula (b) added with acetic acid / potassium iodide / potassium iodate-sodium thiosulfate solution titration method is 550 to 1900 g / mol from the viewpoint of excellent vulcanization reactivity. Is preferably, and more preferably 600 to 1800 g / mol.

-Silane coupling agent represented by Formula (2) Formula (2) is as follows.
Wherein (2), R ²¹ represents an alkoxy group having 1 to 8 carbon atoms. R ²² represents a polyether group having a hydrocarbon group at the end. R ²³ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. R ²⁴ represents a C1-C30 alkylene group. l represents an integer of 1 to 2, m represents an integer of 1 to 2, n represents an integer of 0 to 1, and l, m and n satisfy the relational expression of l + m + n = 3. Plural R ²¹ in the case where l is 2 may be the same as or different from each other, and Plural R ²² in the case where m is 2 may be the same as or different from each other.

(R ²¹ )
In the above formula (2), R ²¹ represents an alkoxy group having 1 to 8 carbon atoms, and in particular, an alkoxy group having 1 to 3 carbon atoms is preferable because a tire excellent in low rolling resistance can be obtained. As a C1-C3 alkoxy group, a methoxy group, an ethoxy group, etc. are mentioned, for example.
(R ²² )
In the above formula (2), R ²² represents a polyether group having a terminal hydrocarbon group. The polyether group is a group having two or more ether bonds.
As a suitable aspect of the polyether group which has a hydrocarbon group at the terminal, the group represented by following formula (5) is mentioned.

(R ⁵¹ )
In the above formula (5), R ⁵¹ represents a linear alkyl group, a linear alkenyl group, or a linear alkynyl group, and a linear alkyl group is preferable among them. As said linear alkyl group, a C1-C20 linear alkyl group is preferable, and a C8-C15 linear alkyl group is more preferable. Specific examples of the linear alkyl group having 8 to 15 carbon atoms include octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group and the like, among which tridecyl group is preferable.
(R ⁵² )
In the above formula (5), R ⁵² represents a linear alkylene group, a linear alkenylene group, or a linear alkynylene group, and a linear alkylene group is preferable among them. As said linear alkylene group, a C1-C2 linear alkylene group is preferable and ethylene group is more preferable.
(P)
In said formula (5), p represents the integer of 1-10, and it is preferable that it is 3-7.
In the above formula (5), * indicates a bonding position.

(R ²³ )
In the formula (2), R ²³ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
(R ²⁴ )
In the above formula (2), R ²⁴ represents an alkylene group having 1 to 30 carbon atoms, among them preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms. As a specific example of a C1-C5 alkylene group, a methylene group, ethylene group, trimethylene group, a propylene group etc. are mentioned, for example.
(L, m, n)
In said formula (2), l represents the integer of 1-2, and it is preferable that it is 1. In said formula (2), m represents the integer of 1-2, and it is preferable that it is 2. n represents an integer of 0 to 1, and is preferably 0. l, m and n satisfy the relational expression of l + m + n = 3.

  Specific examples of the silane coupling agent represented by the formula (2) include 3- [ethoxybis (3,6,9,12,15-pentaoxaoctacosan-1-yloxy) silyl] -1-l. Propanethiol (Evonik Degussa Si 363) may be mentioned.

  The method for producing the silane coupling agent is not particularly limited. For example, conventionally known ones can be mentioned.

  The content of the silane coupling agent is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the silica, from the viewpoint of being excellent by the effect of the present invention (particularly the dispersibility of the silica) and excellent in processability. It is more preferable that it is -15 mass parts.

(Additive)
The composition of the present invention can further contain an additive, as needed, in a range that does not impair the effects and purposes. As the additive, for example, rubber other than diene rubber, filler other than the above silica (for example, carbon black, silica other than the above CTAB adsorption specific surface area range), vulcanization accelerator, resin, zinc oxide, stearic acid Those generally used in tire rubber compositions such as anti-aging agents, processing aids, oils, vulcanizing agents such as sulfur, peroxides and the like can be mentioned. The content of the additive can be appropriately selected.

(Carbon black)
The composition of the present invention may further contain carbon black.
The carbon black is not particularly limited. Examples of carbon black include SAF (Super Abrasion Furnace, hereinafter the same)-HS (High Structure, hereinafter the same), SAF, ISAF (Intermediate Super Abrasion Furnace, hereinafter the same)-HS, ISAF, ISAF, LS (Low Structure). The same applies to the following: IISAF (Intermediate ISAF) -HS, HAF (High Abrasion Furnace, and so on) -HS, HAF, HAF-LS, and various grades such as FEF (Fast Extruding Furnace) can be used.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 50 to 200 m ² / g from the viewpoint of excellent processability. The nitrogen adsorption specific surface area of carbon black shall be measured according to JIS K6217-2.

  1-50 mass parts is preferable with respect to 100 mass parts of diene based rubbers, and, as for content of carbon black, 1-20 mass parts is more preferable.

(Method of producing rubber composition)
The method for producing the composition of the present invention is not particularly limited. Specific examples thereof include, for example, a method of mixing the respective components described above under a condition of 100 to 200 ° C. using a known method and apparatus (for example, a Banbury mixer, a kneader, a roll and the like).
Also, the composition of the present invention can be vulcanized or crosslinked, for example, under conventionally known vulcanization or crosslinking conditions.
The compositions of the present invention can be used, for example, to make tires.
The components of the pneumatic tire that can be made of the composition of the present invention are not particularly limited. Examples of such members include tire treads such as cap treads; sidewalls; and bead fillers.

[Pneumatic tire]
The pneumatic tire of the present invention is a pneumatic tire in which the rubber composition for a tire of the present invention is disposed in a cap tread.
The rubber composition used for the cap tread is not particularly limited as long as it is the rubber composition for a tire of the present invention (the composition of the present invention).
The cap tread is a portion of the pneumatic tire in direct contact with the road surface.
The pneumatic tire of the present invention is not particularly limited except that the composition of the present invention is disposed on the cap tread (the cap tread is formed of the composition of the present invention).
FIG. 1 is a schematic partial cross-sectional view of a tire showing an example of an embodiment of the pneumatic tire according to the present invention. The present invention is not limited to the attached drawings.

In FIG. 1, the pneumatic tire has a bead portion 1, a sidewall portion 2 and a tire tread portion 3. A carcass layer 4 in which a fiber cord is embedded is mounted between a pair of left and right bead portions 1, and the end of the carcass layer 4 is folded outward from the inside of the tire around the bead core 5 and the bead filler 6 It is rolled up. In the tire tread portion 3, a belt layer 7 is disposed on the outer side of the carcass layer 4 over the entire circumference of the tire. In the bead portion 1, a rim cushion 8 is disposed in a portion in contact with the rim.
The tire tread portion 3 has a cap tread on the belt layer 7. An undertread may be disposed between the belt layer 7 and the cap tread.
The above-described composition of the present invention is disposed on the cap tread in the tire tread portion 3.

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

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these.
<< Production of piperazine compound >>
<Synthesis of Piperazine Compound 1>
13.3 g of 1-bromooctadecane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 13.0 g of 1- (2-hydroxyethyl) piperazine (manufactured by Nippon Emulsifier Co., Ltd., hydroxyethyl piperazine) in tetrahydrofuran and dichloromethane at room temperature The reaction was carried out for 1 hour. The reaction solution was washed with aqueous potassium carbonate solution, extracted with dichloromethane and dried over anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off and concentrated to obtain a piperazine compound 1 represented by the following formula.
(Piperazine compound 1)

<Synthesis of Piperazine Compound 2>
39.6 g of the piperazine compound 1 obtained as described above, 13.2 g of ethylene oxide and 0.004 g of sodium methoxide were reacted. The reaction solution was neutralized with phosphoric acid and filtered to obtain a piperazine compound 2 represented by the following formula. N in the following formula is 3.
(Piperazine compound 2)

<Synthesis of Piperazine Compound 3>
66.6 g of 1-bromooctadecane (made by Tokyo Chemical Industry Co., Ltd.) and 19.04 g of piperazine hexahydrate (made by Nippon Emulsifier Co., Ltd., piperazine hexahydrate) in tetrahydrofuran and dichloromethane at room temperature for 1 hour It was made to react. The reaction solution was washed with aqueous potassium carbonate solution, extracted with dichloromethane and dried over anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off and concentrated to obtain a piperazine compound 3 represented by the following formula.
(Piperazine compound 3)

<Synthesis of Piperazine Compound 4>
In toluene, 30.3 g of stearoyl chloride (made by Tokyo Chemical Industry Co., Ltd.), 13.0 g of 1- (2-hydroxyethyl) piperazine (made by Nippon Emulsifier Co., Ltd. hydroxyethyl piperazine) and 15.2 g of triethylamine The reaction was carried out at 0 ° C. for 1 hour. The reaction solution was washed with aqueous sodium carbonate solution, extracted with toluene, and dried over anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off and concentrated to obtain a piperazine compound 4 represented by the following formula.
(Piperazine compound 4)

<Synthesis of Piperazine Compound 5>
60.6 g of stearoyl chloride (made by Tokyo Chemical Industry Co., Ltd.), 19.04 g of piperazine hexahydrate (made by Nippon Emulsifier Co., Ltd., piperazine hexahydrate) and 30.4 g of triethylamine in toluene at 0 ° C. The reaction was carried out for 1 hour under the following conditions. The reaction solution was washed with aqueous sodium carbonate solution, extracted with toluene, and dried over anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off and concentrated to obtain a piperazine compound 5 represented by the following formula.
(Piperazine compound 5)

<Synthesis of Piperazine Compound 6>
18.5 g of 2-ethylhexyl glycidyl ether (Epogorose (registered trademark) 2EH manufactured by Yokkaichi Gosei Co., Ltd.) and 13.0 g of 1- (2-hydroxyethyl) piperazine (manufactured by Nippon Emulsifier Co., Ltd. hydroxyethyl piperazine) The reaction was carried out at 60 ° C. for 4 hours to obtain a piperazine compound 6 represented by the following formula.

The results of ¹ H-NMR of piperazine compound 6 are as follows.
¹ H-NMR (400 MHz, CDCl ₃ ): δ 3.85 (m, 1 H), 3.60 (t, 2 H), 3.30-3.47 (m, 4 H), 2.65 (m, 2 H) ), 2.54 (t, 4H), 2.46 (t, 2H), 2.38 (dd, 2H), 1.52 (q, 1H), 1.26 to 1.41 (m, 8H) , 0.89 (t, 5 H), 0.85 (s, 1 H)
(Piperazine compound 6)

<Synthesis of Piperazine Compound 7>
C12-13 mixed alcohol glycidyl ether (Epogoose (registered trademark) EN manufactured by Yokkaichi Gosei Co., Ltd. Mixture of C12 alcohol glycidyl ether and C13 alcohol glycidyl ether) 28.4 g and 1- (2-hydroxyethyl) piperazine The piperazine compound 7 (R is -C ₁₂ H ₂₅ or R-represented by the following formula) by reacting 13.0 g of Nippon Emulsifier Co., Ltd. hydroxyethyl piperazine) at 60 ° C. for 4 hours. C ₁₃ represents a H _27. piperazine compound 7 to give the R is -C ₁₂ H ₂₅ and is piperazine compound and R is a mixture of piperazine compounds is -C ₁₃ H _27.).
(Piperazine compound 7)

<Synthesis of Piperazine Compound 8>
C. 12-13 mixed alcohol glycidyl ether (manufactured by Yokkaichi Sogo Co., Ltd. Epogoose (registered trademark) EN) 56.8 g, and 19.04 g of piperazine hexahydrate (Nippon Emulsifier Co., Ltd. piperazine hexahydrate), ethanol The reaction was carried out at 60 ° C. for 6 hours. The reaction solution was washed with saturated brine, extracted with ethyl acetate, and dried over anhydrous magnesium sulfate. The magnesium sulfate was filtered off, by concentrating, piperazine compounds 8 (R -C ₁₂ H ₂₅ are each independently, or represents. A -C ₁₃ H ₂₇₎ represented by the following formula was obtained.
(Piperazine compound 8)

<Synthesis of Morpholine Compound 1>
33.3 g of 1-bromooctadecane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 8.7 g of morpholine (manufactured by Tokyo Chemical Industry Co., Ltd.) were reacted in tetrahydrofuran and dichloromethane at room temperature for 1 hour.
The reaction solution was washed with aqueous potassium carbonate solution, extracted with dichloromethane and dried over anhydrous magnesium sulfate. Anhydrous magnesium sulfate was filtered off and concentrated to obtain morpholine compound 1 (the following structure).
(Morpholine compound 1)

<< Production of composition for tire >>
Each component of following Table 1 was mix | blended by the composition (mass part) shown to the same table.
Specifically, first, among the components shown in Table 1 below, after raising the temperature to about 150 ° C. using a 1.7 liter closed Banbury mixer, the components other than sulfur and the vulcanization accelerator After mixing for a minute, it was discharged and cooled to room temperature to obtain a masterbatch. Furthermore, using the above-mentioned Banbury mixer, the obtained masterbatch was mixed with sulfur and a vulcanization accelerator to obtain a rubber composition for a tire.
In Table 1, with regard to the amount of SBR, the value in the upper row is the amount of rubber (oil extending product) (unit: mass part), and the value in the lower row is the net amount of rubber (unit: mass portion) .

<Evaluation>
The following evaluation was performed using the composition manufactured as mentioned above. The results are shown in Table 1 respectively.

(Abrasion resistance)
A rubber composition for a tire (unvulcanized) produced as described above was press-cured at 160 ° C. for 20 minutes in a mold (15 cm × 15 cm × 0.2 cm) to produce a vulcanized rubber sheet.
Using the above-mentioned vulcanized rubber sheet, in accordance with JIS K6264, using a Lambourn abrasion tester (manufactured by Iwamoto Seisakusho Co., Ltd.), measure the wear volume at a load of 49 N, a slip ratio of 25%, a time of 4 minutes and room temperature did.
The results were indexed by the following equation, where the wear volume of the standard example is 100.
Wear resistance = (Wear volume of standard example / Wear volume of each sample) x 100
The larger the index, the smaller the amount of wear, and the more excellent the wear resistance when made into a tire.

(Wet grip performance)
The obtained rubber composition for a tire (unvulcanized) was press-cured at 160 ° C. for 20 minutes in a mold (15 cm × 15 cm × 0.2 cm) to produce a vulcanized rubber sheet.
With respect to the produced vulcanized rubber sheet, in accordance with JIS K 6394: 2007, using a visco-elastic spectrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.), a condition of an elongation deformation strain rate of 10% ± 2%, a frequency of 20 Hz and a temperature of 0 ° C. The tan δ (0 ° C.) was measured.
In Table 1, the evaluation result of the wet grip performance of each example and comparative example is an index [(tan δ (0 ° C.) / Standard example of each example or comparative example)] on the basis of the evaluation result (100) of the standard example. (0 ° C.)) × 100].
In the present invention, when the above index exceeds 100, tan δ (0 ° C.) is large, and when it is used as a tire, the wet grip performance is excellent. Also, the larger the index, the better the wet grip performance.

(Low rolling resistance)
In place of the measurement at a temperature of 0 ° C., tan δ (60 ° C.) was measured according to the same procedure as the wet grip performance described above except that the measurement was performed at a temperature of 60 ° C.
In Table 1, regarding the evaluation results of low rolling resistance, the result of tan δ (60 ° C.) of the standard example is expressed as 100, and the results of each example and comparative example are (tan δ (60 ° C. of the standard example) / each execution The results are expressed as index of tan δ (60 ° C.) × 100 of the example or the comparative example.
(60 ° C.) is smaller as the index is larger, and when it is made into a tire, it is excellent in low rolling resistance.

(Pane effect)
The rubber composition for a tire produced as described above is subjected to strain stress 0.28% strain 0.28% under RPA 2000 (strain shear stress tester manufactured by α-Technology) under the condition of 110 ° C. according to ASTM D6204. '(0.28%) and strain shear stress G' (450%) of strain 450% were measured, and [Delta] G '= G' (0.28%)-G '(450%) was calculated.
In Table 1, with respect to the evaluation result of the Payne effect, the result of ΔG 'of the standard example is expressed as 100, and the results of each example and comparative example are (ΔG' of standard example / ΔG 'of each example or comparative example) Exponentially expressed as × 100.
The larger the index, the better the reduction or suppression of the Payne effect (the better the dispersibility of the silane).

The detail of each component shown to said each table | surface is as follows.
SBR 1: Solution-polymerized styrene-butadiene rubber having a hydroxy group as a terminal modifying group for silica. SBR1 corresponds to a diene rubber. Tufden E 580 (including oil-extended products (37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR. Net of SBR in SBR 1 is 72.7% by mass), styrene content: 37% by mass, vinyl bond: 42%, Tg: −27 ° C., weight average molecular weight: 1,260,000, manufactured by Asahi Kasei Corp. SBR 1 is a styrene butadiene rubber having a hydroxy group as a terminal modifying group for silica, so it interacts with silica in the modifying group or It can react.

-BR: Butadiene rubber, Nipol 1220 (Butadiene rubber, manufactured by Nippon Zeon Co., Ltd.), Tg-105 ° C. The above BR corresponds to a diene rubber. The above BR does not have a modifying group.

Silica 1: Nipsil KQ manufactured by Tosoh Silica Corporation, CTAB adsorption specific surface area 214 m ² / g

-Carbon black: Seast KH N 339 (N ₂ SA = 93 m ² / g, manufactured by Tokai Carbon Co., Ltd.)

  Silane coupling agent 1: Si 69 (bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Evonik Degussa Co., Ltd.)

・ Zinc oxide: Three kinds of zinc oxide (manufactured by Shodo Chemical Industry Co., Ltd.)
-Stearic acid: beads stearic acid YR (made by NOF Corporation)
・ Anti-aging agent: 6PPD (made by Flexis)
Process oil: Extract No. 4S (manufactured by Showa Shell Sekiyu KK)

  -Alkyl triethoxysilane: octyl triethoxysilane (KBE-3083, manufactured by Shin-Etsu Silicone Co., Ltd.)

  Piperazine Compound 7: The piperazine compound 7 synthesized as described above

  Morpholine compound 1: Morpholine compound 1 synthesized as described above

Comparative piperazine compound 1: Hydroxyethyl piperazine, 1- (2-hydroxyethyl) piperazine manufactured by Nippon Emulsifier Co. Comparative piperazine compound 2: Reagent [3- (1-piperazinyl) propyl] triethoxysilane). Comparative piperazine compound 2 has a silicon atom.

・ Sulfur: Fine powder sulfur with gold oxide oil (made by Tsurumi Chemical Industry Co., Ltd.)
Vulcanization accelerator 1: Noxceler CZ-G (Vulcanization accelerator CBS, manufactured by Ouchi Shinko Chemical Co., Ltd.)
Vulcanization accelerator 2: Noxceler D (Vulcanization accelerator DPG, manufactured by Ouchi Shinko Chemical Co., Ltd.)

As is clear from the results shown in Table 1, Comparative Example 1 in which the content of silica is less than the predetermined range was inferior in abrasion resistance and wet grip performance to the standard example.
Comparative Example 2 in which the content of silica is larger than the predetermined range was inferior in low rolling resistance and dispersibility of silica to the standard example.
The comparative example 3 which does not contain predetermined | prescribed alkyl triethoxysilane was inferior to the standard example in low rolling resistance, wet grip performance, and the dispersibility of a silica.
Comparative Example 4 which does not contain a predetermined heterocyclic compound but, instead, contains a piperazine compound having a hydroxyethyl group has better abrasion resistance, low rolling resistance, wet grip performance, silica dispersibility than the standard example. It was inferior to.
Comparative Example 5 which does not contain a predetermined heterocyclic compound but, instead, contains a piperazine compound having a silicon atom is more excellent in abrasion resistance, low rolling resistance, wet grip performance, silica dispersibility than the standard example. inferior.

  On the other hand, the composition of the present invention was excellent in the dispersibility of silica, and was able to ensure excellent abrasion resistance while maintaining wet grip performance and low rolling resistance at high levels.

1 bead portion 2 side wall portion 3 tire tread portion 4 carcass layer 5 bead core 6 bead filler 7 belt layer 8 rim cushion

Claims (7)

With diene rubber,
Silica having a CTAB adsorption specific surface area of 210 to 300 m ² / g,
A heterocyclic compound having a hydrocarbon group having a carbon number of 3 to 30, and at least one hetero ring selected from the group consisting of a piperazine ring, a morpholine ring and a thiomorpholine ring (provided that the heterocyclic compound has a silicon atom) Not) and
And alkyltriethoxysilane having an alkyl group of 3 to 20 carbon atoms,
The content of the silica is 80 to 150 parts by mass with respect to 100 parts by mass of the diene rubber,
The content of the heterocyclic compound is 0.5 to 20% by mass with respect to the silica,
The rubber composition for tires, whose content of the said alkyl triethoxysilane is 0.5-20 mass parts with respect to the said diene rubber. The rubber composition for a tire according to claim 1, wherein the heterocyclic compound is a compound represented by the following formula (I).
In formula (I), X ₇ represents at least one selected from the group consisting of nitrogen atom, oxygen atom and sulfur atom,
Each of X ₃ , X ₄ , X ₅ and X ₆ independently represents a hydrogen atom or a hydrocarbon group.
When X ₇ is a nitrogen atom, n 3 is 1, and one or both of X ₁ and X ₂ are each independently a group of the formula (I-1):-(A ₁ ) _{n 1-1-} R _{1 Represents -1} ,
When only one of X ₁ and X ₂ represents the formula (I-1), the remaining groups are a hydrogen atom, a sulfone-based protecting group, a carbamate-based protecting group and a formula (I-3):-(R ₂ ) -O) represents at least one selected from the group consisting of _n2- H,
In formula (I-3), each R ₂ independently represents a divalent hydrocarbon group,
n2 represents 1 to 10;
When X ₇ is at least one selected from the group consisting of an oxygen atom and a sulfur atom, n 3 represents 0, and X ₁ represents a group of the formula (I-1):-(A ₁ ) _{n 1-1-} R _1- It represents _1.
In formula (I-1), A ₁ represents at least one member selected from the group consisting of a carbonyl group and formula (I-2): -R _1-2 (OH) -O-,
n1-1 represents 0 or 1 and
R _1-1 represents a hydrocarbon group having 3 to 30 carbon atoms,
In formula (I-2), R _1-2 represents a trivalent hydrocarbon group. The heterocyclic compound is a compound represented by the formula (I), X ₇ is a nitrogen atom, and n 3 is 1.
The tire rubber composition according to claim 2, wherein both X ₁ and X ₂ independently represent the formula (I-1). The heterocyclic compound is a compound represented by the formula (I), X ₇ is a nitrogen atom, and n 3 is 1.
Only one of X ₁ and X ₂ represents the formula (I-1),
The remaining groups, represents at least one hydrogen atom, sulfone protecting groups, carbamate protecting groups and formula (I-3) is selected from :-( R ₂ -O) group consisting of _n2 -H, claim 2 The rubber composition for a tire as described in 4. In formula (I-3), each R ₂ independently represents a divalent hydrocarbon group, and n ₂ represents 1 to 10.   Furthermore, the rubber composition for tires of any one of Claims 1-4 containing a silane coupling agent. The diene rubber comprises a modified diene rubber,
The rubber composition for a tire according to any one of claims 1 to 5, wherein the content of the modified diene rubber exceeds 50% by mass in the total amount of the diene rubber.   The pneumatic tire which arrange | positioned the rubber composition for tires of any one of Claims 1-6 to the cap tread.