JP2001240706A - Rubber composition and pneumatic tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition of which the wet performance, low fuel consumption properties, and abrasion resistance are well balanced and which is suitable for tire treads. SOLUTION: This composition contains (A) 100 pts.wt. rubber component containing at least 30 wt.% modified diene polymer prepared by reacting a hydrocarbyloxysilane compound represented by formula (I) or (II), wherein R1, R2, R5, and R6 are each 1-18C monovalent hydrocarbon group; A1 and A2 are each a 120C divalent hydrocarbon group; R3 and R4 are each a 1-18C monovalent hydrocarbon group optionally having an optionally substituted amino and/or ether group or groups; R7 and R8 are each H or a 1-18C monovalent hydrocarbon group optionally having an optionally substituted amino and/or ether group or groups; and n and m are each 1, 2 or 3 with the polymerization- active molecular ends of a diene polymer and (B) 3-60 pts.wt. aluminum hydroxide powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition and a pneumatic tire using the same. For more information,
The present invention uses a modified diene polymer having a high interaction with a reinforcing filler such as aluminum hydroxide as a rubber component, while maintaining good wet performance and low fuel consumption, and having abrasion resistance. The present invention relates to an improved rubber composition and a pneumatic tire using the rubber composition.

[0002]

2. Description of the Related Art Conventionally, carbon black has been frequently used as a reinforcing filler for rubber. This is because carbon black can provide high reinforcing properties and excellent wear resistance as compared with other fillers. On the other hand, in response to recent social demands for energy saving, in order to reduce the fuel consumption of automobiles, to reduce the heat generation of the rubber for tires, that is, to reduce the rolling resistance, the amount of filling of carbon black is reduced, or the size of large particles is reduced. The use of carbon black is conceivable, but in any case, it is known that reinforcement, abrasion resistance and grip on wet road surfaces are inevitable.

On the other hand, hydrated silica (wet silica) is known as a filler material that achieves both low heat build-up, reinforcement, wear resistance, and grip on wet road surfaces.
-252431, JP-A-6-248116, JP-A-7-70369, JP-A-7-1884
No. 66, JP-A-7-196850, JP-A-8-196
Numerous patents have been filed, such as JP-A-225684, JP-A-8-245838, and JP-A-8-337687. However, this hydrous silicic acid is
Compared with carbon black having the same specific surface area, the rubber composition containing the same has a drawback that the storage elastic modulus of the rubber composition is small, so that the exercise performance on dry road surfaces is inferior. As a method of increasing the storage elastic modulus, increasing the filling amount of hydrous silicic acid, increasing the specific surface area of hydrous silicic acid, and the like, in any case, the low heat buildup characteristic of hydrous silicic acid is known. There is a problem of lowering.

As a means for improving grip on wet road surfaces, it is known to increase the glass transition temperature (Tg) of rubber, that is, tan δ at 0 ° C. However, when the Tg of the rubber is increased, the low-temperature performance is reduced, and the rolling resistance is increased, that is, the fuel efficiency is deteriorated. In order to solve these problems, various techniques such as (1) a rubber composition for a tire tread in which grip properties on wet road surfaces are improved by special silica and kneading techniques (European Patent No. 501227) (2) A rubber composition for a tire tread which has improved wet skid performance while maintaining low heat build-up without reducing workability and abrasion resistance (Japanese Patent Laid-Open No. 149950/1995). ) A rubber composition for a tire tread having improved grip and workability on a wet road surface or a semi-wet road surface in a low temperature region and a high temperature region (Japanese Patent Application Laid-Open No. 8-59893), (4) without impairing the wear resistance, Rubber compositions for tire treads with improved grip on wet and semi-wet road surfaces in low and high temperature regions (Japanese Patent Application Laid-Open No. Hei 8-59894). There has been disclosed. However, the above (1)
The rubber composition of (1) has a problem in workability (workability), and the rubber composition of (2) is not sufficient in abrasion resistance. In the rubber compositions of (3) and (4),
There is a problem that the amount of the reinforcing filler is too large.

On the other hand, aluminum hydroxide is known as a reinforcing filler for rubber. Tires using a rubber composition containing this aluminum hydroxide in a tire tread have good wet performances such as grip on wet road surfaces, and have low fuel consumption, but have poor wear resistance. Have. By the way, in order to obtain a rubber composition with low heat generation, many technical developments have been made to enhance the dispersibility of a filler used in the rubber composition.
Among them, a method of modifying the polymerization active terminal of a diene polymer obtained by anionic polymerization using an organic lithium compound with a functional group having an interaction with a filler is becoming the most common method. For example, a rubber composition using a rubber material using silica as a reinforcing filler and modifying a polymerization active terminal of a diene polymer obtained by anionic polymerization with a silicon compound having an alkoxyl group (Japanese Patent Publication No. 6
-57767, JP-A-7-233216,
Japanese Patent Application Laid-Open No. 9-87426) is disclosed.
However, even in such a rubber composition, all of the wet performance, fuel economy and abrasion resistance cannot always be sufficiently satisfied.

[0005]

SUMMARY OF THE INVENTION The present invention provides a rubber composition which balances wet performance, low fuel consumption and abrasion resistance under such circumstances, and a pneumatic tire using the rubber composition. It is intended to provide.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, focused on good wet performance and low fuel consumption of aluminum hydroxide, As a rubber composition using aluminum hydroxide and optionally carbon black or silica, and a rubber component containing a specific modified diene-based polymer that has increased interaction with these reinforcing fillers And found that it could achieve its purpose. The present invention has been completed based on such findings. That is, the present invention relates to (A) a compound represented by the general formula (I)

[0007]

Embedded image

Wherein R ¹ and R ² are each a monovalent hydrocarbon group having 1 to 18 carbon atoms, A ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms, and R ³ and R ⁴ are A monovalent hydrocarbon group having 1 to 18 carbon atoms which may have an unsubstituted or substituted amino group and / or an ether group, and n represents 1 to 3
Indicates the integer, when R ¹ O is more, each R ¹ O may be the same as or different from each other, when R ² are a plurality, each R ² may be the same with or different from each other. R ³ and R ⁴ may be the same or different from each other, and may further form a saturated or unsaturated ring structure together with the nitrogen atom to which R ³ and R ⁴ are bonded. Good. The aminohydrocarbyloxysilane compound represented by the general formula (II)

[0009]

Embedded image

Wherein R ⁵ and R ⁶ are each a monovalent hydrocarbon group having 1 to 18 carbon atoms, A ² is a divalent hydrocarbon group having 1 to 20 carbon atoms, and R ⁷ and R ⁸ are each represent a hydrogen atom, or an unsubstituted or substituted amino group and / or ether groups and having 1 to 18 carbon atoms which may have a monovalent hydrocarbon group, m is an integer of 1 to 3, R ⁵ O When there are two or more, each R ⁵ O may be the same or different,
When there are a plurality of R ⁶ , each R ⁶ may be the same or different. R ⁷ and R ⁸ may be the same or different from each other, and may be further bonded to each other to form a ring structure. A) a rubber component containing at least 30% by weight of a modified diene polymer obtained by reacting an imino group-containing hydrocarbyloxysilane compound represented by the formula (1), and (B) 3 to 60 parts by weight of aluminum hydroxide powder per 100 parts by weight of the rubber component The present invention provides a rubber composition characterized by containing a carbon black and / or silica powder as a component (C). The present invention also provides a pneumatic tire using the rubber composition as a tread rubber.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the rubber composition of the present invention,
As the component (A), one containing a modified diene polymer is used. The modified diene polymer is obtained by reacting an aminohydrocarbyloxysilane compound having a specific structure or an imino group-containing hydrocarbyloxysilane compound with a polymerization active terminal of the diene polymer. The diene polymer used as a raw material of the modified diene polymer may be produced, for example, by using an organolithium compound as a polymerization initiator and anionically polymerizing a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound. Can be.

Examples of the conjugated diene compound include 1,3-butadiene; isoprene; 1,3-pentadiene; 2,3-dimethylbutadiene; 2-phenyl-1,
3-butadiene; 1,3-hexadiene and the like. These may be used alone or in combination of two or more. Among them, 1,3-butadiene is particularly preferred. Examples of the aromatic vinyl compound used for copolymerization with these conjugated diene compounds include styrene; α-methylstyrene; 1-vinylnaphthalene; 3-vinyltoluene; ethylvinylbenzene; divinylbenzene; and 4-cyclohexylstyrene. ; 2
4,6-trimethylstyrene and the like. These may be used alone or in combination of two or more. Among them, styrene is particularly preferred.

Further, when copolymerization is carried out using a conjugated diene compound and an aromatic vinyl compound as monomers, the use of 1,3-butadiene and styrene, respectively, makes practical use such as easy availability of monomers. And anionic polymerization characteristics are excellent in terms of living properties and the like. As the organic lithium compound of the polymerization initiator, hydrocarbyl lithium and lithium amide compounds are preferably used.When the former hydrocarbyl lithium is used, one end has a hydrogen atom and the other end is a polymerization active end. A certain conjugated diene polymer is obtained. When the latter lithium amide compound is used, a conjugated diene polymer having a nitrogen-containing group at one terminal and a polymerization active terminal at the other terminal is obtained. As the above hydrocarbyl lithium, those having a hydrocarbyl group having 2 to 20 carbon atoms are preferable. For example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium
tert-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, cyclopentyl lithium, reaction product of diisopropenylbenzene and butyl lithium Among them, n-butyllithium is preferable.

On the other hand, examples of the lithium amide compound include lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene diimide, lithium dodecamethylene imide, lithium dimethyl amide, lithium diethyl amide, lithium dibutyl amide, and lithium dipropyl amide. Amide, lithium diheptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide,
Examples thereof include lithium didecylamide, lithium-N-methylpiperazide, lithium ethylpropylamide, lithium ethylbutylamide, lithium methylbutylamide, lithium ethylbenzylamide, and lithium methylphenethylamide. Among these, cyclic lithium amides such as lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, and lithium dodecamethylene imide are preferable, and lithium hexamethylene imide and lithium pyrrolidide are particularly preferable. .

The method for producing a conjugated diene polymer by anionic polymerization using the above-mentioned organic lithium compound as a polymerization initiator is not particularly limited, and a conventionally known method can be used. Specifically, an organic solvent inert to the reaction, for example, an aliphatic, alicyclic, in a hydrocarbon solvent such as an aromatic hydrocarbon compound, a conjugated diene compound or a conjugated diene compound and an aromatic vinyl compound, The desired conjugated diene-based polymer can be obtained by anionically polymerizing an organic lithium compound as a polymerization initiator, if desired, in the presence of a randomizer used. The temperature in this polymerization reaction is selected in the range of usually -80 to 150C, preferably -20 to 100C. The polymerization reaction can be carried out under the pressure generated, but it is usually desirable to operate at a pressure sufficient to keep the monomer in a substantially liquid phase. That is, the pressure will depend on the particular materials to be polymerized, the polymerization medium used and the polymerization temperature, but higher pressures can be used if desired, and such pressures are maintained in the reactor with an inert gas for the polymerization reaction. Is obtained by an appropriate method such as pressurization. In the present invention, the modified diene-based polymer used as the rubber component has a polymerization active end of the diene-based polymer, for example, obtained as described above, having a hydrogen atom or a nitrogen-containing group at one end, and The other end of the conjugated diene-based polymer having a polymerization active terminal,
General formula (I)

[0016]

Embedded image

An aminohydrocarbyloxysilane compound represented by the general formula (II):

[0018]

Embedded image

It is obtained by reacting an imino group-containing hydrocarbyloxysilane compound represented by the following formula: In the general formula (I), R ¹ and R ² each represent a monovalent hydrocarbon group having 1 to 18 carbon atoms. Examples of the monovalent hydrocarbon group include an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and an aralkyl group having 7 to 18 carbon atoms. Can be. Here, the alkyl group and the alkenyl group may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Isobutyl group,
sec-butyl group, tert-butyl group, pentyl group,
Examples include hexyl, octyl, decyl, dodecyl, cyclopentyl, cyclohexyl, vinyl, propenyl, allyl, hexenyl, octenyl, cyclopentenyl, cyclohexenyl and the like.

The aryl group may have a substituent such as a lower alkyl group on the aromatic ring, and examples thereof include a phenyl group, a tolyl group, a xylyl group and a naphthyl group. Further, the aralkyl group may have a substituent such as a lower alkyl group on the aromatic ring, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group. A ¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms. Examples of the divalent hydrocarbon group include an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, and an aralkylene group having 7 to 20 carbon atoms. However, among these, an alkylene group having 1 to 20 carbon atoms is preferable.
The alkylene group may be linear, branched, or cyclic, but is preferably a linear one. Examples of the linear alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, and a dodecamethylene group. n
Is an integer of 1 to 3, if R ¹ O is more, each R ¹
O may be the same with or different from each other, when R ² are a plurality, each R ² may be the same with or different from each other.

On the other hand, R ³ and R ⁴ each represent a monovalent hydrocarbon group having 1 to 18 carbon atoms which may have an unsubstituted or substituted amino group and / or an ether group. Carbon number 1
To 18 monovalent hydrocarbon groups include the aforementioned R ¹ and R ²
And R ³ and R ⁴ may have an unsubstituted or substituted amino group and / or an ether group. Examples of the monovalent hydrocarbon group having 1 to 18 carbon atoms having an unsubstituted or substituted amino group or an ether group include a dimethylaminomethyl group, a 2-dimethylaminoethyl group, a 3-dimethylaminopropyl group, and a p- Dimethylaminobenzyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, p-methoxybenzyl, ethoxymethyl, 2
-Ethoxyethyl group, 3-ethoxypropyl group, p-ethoxybenzyl group and the like. R ³ and R ⁴ may be the same or different from each other, and further form a saturated or unsaturated ring structure together with the nitrogen atom to which R ³ and R ⁴ are bonded. Is also good. Among the aminohydrocarbyloxysilane compounds represented by the general formula (I), general formula (Ia)

[0022]

Embedded image

(Wherein, R ⁹ and R ¹⁰ each represent an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms or an aralkyl group having 7 to 18 carbon atoms, each of which is the same. Or different, R ¹ , R ² ,
A ¹ and n are the same as described above. Or a disubstituted amino group-containing hydrocarbyloxysilane compound represented by general formula (Ib):

[0024]

Embedded image

(Wherein Q is a group having 2 to 2 carbon atoms which may be interrupted by at least one of a nitrogen atom and / or an oxygen atom)
20 represents an alkylene group or alkenylene group, R ¹ ,
R ² , A ¹ and n are the same as described above. )) Are preferred. As the cyclic amino group in the cyclic amino group-containing hydrocarbyloxysilane compound represented by the general formula (Ib), for example, 1-pyrrolidinyl group; piperidino group; 1-hexamethyleneimino group; 1-heptamethyleneimino group; 1-octamethyleneimino group; 1-decamethyleneimino group; 1-dodecamethyleneimino group; 1-tetradecamethyleneimino group;
1-polymethyleneimino group such as octadecamethyleneimino group, further 1-imidazolyl group; 4,5-dihydro-1-imidazolyl group (2-imidazolin-1-yl group); 1-imidazolidinyl group; 1-piperazinyl Group;
A morpholino group; a 4-oxazolin-3-yl group; among them, a 1-hexamethyleneimino group and a 4,5-dihydro-1-imidazolyl group are preferable.

Examples of the disubstituted amino group-containing hydrocarbyloxysilane compound represented by the formula (Ia) include 3-dimethylaminopropyl (triethoxy) silane, 3-dimethylaminopropyl (trimethoxy) silane; -Diethylaminopropyl (triethoxy) silane, 3-diethylaminopropyl (trimethoxy) silane, 2-dimethylaminoethyl (triethoxy) silane, 2-dimethylaminoethyl (triethoxy) silane, 3-dimethylaminopropyl (diethoxy) methylsilane, 3-dibutyl Aminopropyl (triethoxy)
Examples include silane. In addition, the general formula (Ib)
Examples of the cyclic amino group-containing hydrocarbyloxysilane compound represented by are 3- (1-hexamethyleneimino) propyl (triethoxy) silane, 3- (1-hexamethyleneimino) propyl (trimethoxy) silane,
(1-hexamethyleneimino) methyl (trimethoxy)
Silane, (1-hexamethyleneimino) methyl (triethoxy) silane, 2- (1-hexamethyleneimino) ethyl (triethoxy) silane, 2- (1-hexamethyleneimino) ethyl (trimethoxy) silane, 3- (1-
Pyrrolidinyl) propyl (triethoxy) silane, 3-
(1-pyrrolidinyl) propyl (trimethoxy) silane, 3- (1-heptamethyleneimino) propyl (triethoxy) silane, 3- (1-dodecamethyleneimino)
Propyl (triethoxy) silane, 3- (1-hexamethyleneimino) propyl (diethoxy) methylsilane,
3- (1-hexamethyleneimino) propyl (diethoxy) ethylsilane, 1- [3- (triethoxysilyl)
Propyl] -4,5-dihydroimidazole, 1- [3
-(Trimethoxysilyl) propyl] -4,5-dihydroimidazole, 3- [10- (triethoxysilyl)
Decyl] -4-oxazoline and the like.

The cyclic amino group-containing hydrocarbyloxysilane compound represented by the general formula (Ib) is more effective than the disubstituted amino group-containing hydrocarbyloxysilane compound represented by the general formula (Ia). In particular, 3- (1-hexamethyleneimino) propyl (triethoxy) silane, (1-hexamethyleneimino) methyl (trimethoxy) silane, 1- [3- (triethoxysilyl) propyl] -4, Preferable examples include 5-dihydroimidazole and 1- [3- (trimethoxysilyl) propyl] -4,5-dihydroimidazole. In particular, 1- [3- (triethoxysilyl)
Propyl] -4,5-dihydroimidazole is preferred in view of the dispersing effect and the reinforcing effect of the filler.

On the other hand, in the general formula (II), R ⁵ and R ⁶ each represent a monovalent hydrocarbon group having 1 to 18 carbon atoms. This monovalent hydrocarbon group is as described for R ¹ and R ² in the general formula (I). A ² represents a divalent hydrocarbon group having 1 to 20 carbon atoms. The divalent hydrocarbon group is as described for A ¹ in the general formula (I). m is an integer of 1 to 3, if R ⁵ O is more, each R ⁵ O may be the same as or different from each other, if R ⁶ is more, each R ⁶ is the same with or different from each other You may.

On the other hand, R ⁷ and R ⁸ each represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms which may have an unsubstituted or substituted amino group and / or an ether group. The monovalent hydrocarbon group having 1 to 18 carbon atoms is as described for R ¹ and R ² in the formula (I), and R ⁷ and R ⁸ are an unsubstituted or substituted amino group. Or it may have an ether group or both. R ⁷ and R ⁸ may be the same or different from each other, and may be further bonded to each other to form a ring structure. This ring structure may be a saturated or unsaturated hydrocarbon structure, or may be a saturated or unsaturated heterocyclic structure having a nitrogen atom and / or an oxygen atom as a hetero atom. The general formula (I
In I), the imino group bonded to A ² includes, for example, an ethylideneamino group; a 1-methylpropylideneamino group; a 1,3-dimethylbutylideneamino group; a 1-methylethylideneamino group; Preferred examples include a dimethylaminobenzylideneamino group; a cyclohexylideneamino group, and the like.

Examples of the imino group-containing hydrocarbyloxysilane compound represented by the general formula (II) include N-
(1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, N- (1-methylethylidene) -3- (triethoxysilyl) -1-propanamine, N-ethylidene-3 -(Triethoxysilyl)
-1-propanamine, N- (1-methylpropylidene) -3- (triethoxysilyl) -1-propanamine, N- (4-N, N-dimethylaminobenzylidene)
-3- (triethoxysilyl) -1-propanamine,
N- (cyclohexylidene) -3- (triethoxysilyl) -1-propanamine and trimethoxysilyl, methyldiethoxysilyl, ethyldiethoxysilyl and methyldimethoxysilyl compounds corresponding to these triethoxysilyl compounds Compounds, ethyldimethoxysilyl compounds and the like are preferred. Among them, N- (1-methylpropylidene) -3- (triethoxysilyl) -1-propanamine and N-
(1,3-Dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine is preferred.

When the above-mentioned aminohydrocarbyloxysilane compound or imino group-containing hydrocarbyloxysilane compound (hereinafter sometimes referred to as a terminal modifier) is reacted with the polymerization active terminal of the conjugated diene-based polymer, The amount of the terminal modifier used is usually 0.25 to 3.0 mol, preferably 0.5 to 1 mol, per 1 mol of the organolithium compound used for producing the conjugated diene polymer.
5 moles. If the amount is less than 0.25 mol, hydrocarbyloxy groups are undesirably consumed in the coupling reaction. If the amount exceeds 3 moles, excess terminal modifier is wasted, and impurities contained in the terminal modifier deactivate the polymerization active terminal, thereby lowering the substantial modification efficiency, which is not preferable. The reaction temperature at this time may be the polymerization temperature of the conjugated diene polymer. Specifically, 30 to 100 ° C. is mentioned as a preferable range. If the temperature is lower than 30 ° C., the viscosity of the polymer tends to be too high, and if it is higher than 100 ° C., the polymerization active terminal is easily deactivated, which is not preferable.

The timing and method of adding the above-mentioned terminal modifier to the polymerization active terminal of the conjugated diene-based polymer are not particularly limited. Generally, when such a terminal modifier is used, it is carried out after completion of the polymerization. Often. The analysis of the modified group at the terminal of the polymer chain of the modified conjugated diene-based polymer thus obtained can be performed by using high performance liquid chromatography (HPLC). When the aminohydrocarbyloxysilane compound represented by the general formula (I) is reacted with the polymerization active terminal of the conjugated diene polymer, the reaction with the hydrocarbyloxysilane is required as shown in the following formula (III). It is believed that a nuclear replacement product is obtained.

[0033]

Embedded image

(In the formula, R ^{1 to} R ⁴ , A ¹ and n are the same as described above.) The terminal of the modified conjugated diene polymer produced by this nucleophilic substitution reaction is represented by the formula (III) As shown, through the silicon atom, there will be both n-1 hydrocarbyloxy groups and a nitrogen-containing group. Among them, regarding the hydrocarbyloxy group, when this modified conjugated diene-based polymer is blended with aluminum hydroxide, for example, the compound represented by the formula (IV)

[0035]

Embedded image

(Wherein R ^{1 to} R ⁴ , A ¹ and n are the same as described above), a chemical bond is formed by a condensation reaction with a hydroxyl group of aluminum hydroxide.
Therefore, in this case, n is preferably 2 or 3. The reason is that when n is 1, the hydrocarbyloxy group is consumed in the nucleophilic substitution reaction to the terminal of the conjugated diene polymer, and is not present for the condensation reaction of aluminum hydroxide with the hydroxyl group. This is because a condensation reaction with a hydroxyl group is not considered to occur. Also, when silica is blended, a chemical bond is generated by a condensation reaction in the same manner as a silanol group which is a surface functional group of silica.

The condensation reaction between the hydroxyl group of aluminum hydroxide and the silanol group, which is a surface functional group of silica, and the interaction between aluminum hydroxide, silica and carbon black having a nitrogen-containing group have a synergistic effect. It can be expected that the dispersing effect and the reinforcing effect of the material can be simultaneously provided. Among the terminal modifiers, when a cyclic amino group-containing hydrocarbyloxysilane compound is used,
A modified conjugated diene-based polymer exhibiting a good dispersing effect on aluminum hydroxide, silica and carbon black can be obtained. In particular, an aminohydrocarbyloxysilane compound having a strongly basic dihydroimidazolyl group,
When the terminal of the conjugated diene polymer is modified, such a highly basic functional group has an extremely strong interaction with aluminum hydroxide, silica and carbon black. A conjugated diene polymer is obtained.

On the other hand, the imino group-containing hydrocarbyloxysilane compound represented by the general formula (II) has a methyleneamino group in the molecule.
It has excellent basicity like a tertiary amino group and has little steric hindrance, so it is easy to develop various acidic functional groups and good hydrogen bonding strength. When this terminal modifier is reacted with a polymerization active terminal of a conjugated diene polymer, as shown by the following formula (V), the addition of a nucleophilic substitution product with hydrocarbyloxysilane to a methyleneamino group is performed. It is believed that a mixture of reaction products is obtained. That is, when a nucleophilic substitution reaction is carried out at the polymerization active terminal of the polymer, an interaction is generated between the hydroxyl group of aluminum hydroxide or the acidic functional group on the silica surface and the introduced methyleneamino group, resulting in good hydroxylation. It can be expected that the effect of dispersing aluminum and silica and the effect of reinforcement are simultaneously provided. Also, when added to the polymerization active terminal of the polymer, it is converted to a secondary amine. Even in such a case, good dispersibility of aluminum hydroxide and silica can be expected due to the secondary amine having a high hydrogen bonding property with the hydroxyl group of aluminum hydroxide and the silanol group on the silica surface.

[0039]

Embedded image

(The formulas, R ^{5 to} R ⁸ , A ² and m are the same as described above.) Further, the terminal modifier has a hydrocarbyloxysilyl group, and is provided at the polymerizable active terminal of the polymer. The introduced hydrocarbyloxysilyl group undergoes a condensation reaction with a hydroxyl group of aluminum hydroxide or a silanol group on the silica surface, thereby providing an extremely high reinforcing effect due to a synergistic effect with the hydrogen bonding force of the methyleneamino group. . Further, when the imino group bonded to A ² is an N, N-dimethylaminobenzylideneamino group, if carbon black is used together with aluminum hydroxide or silica as a filler, the interaction between carbon black is more favorable. A great reinforcing effect can be obtained. As described above, this modified conjugated diene-based polymer can obtain a good reinforcing property in the aluminum hydroxide compounding, or a mixed compounding of aluminum hydroxide and silica or carbon black, and provide a rubber composition having excellent wear characteristics. Can be given.

The modified diene polymer used in the present invention preferably has a glass transition point (Tg) of -90 to -30 ° C. measured by a differential scanning calorimeter (DSC).
It is difficult to obtain a polymer having a temperature of less than -90 ° C in a usual anionic polymerization formulation, and a polymer having a temperature of more than -30 ° C becomes hard in a room temperature range, which is not preferable for use as a rubber-like elastic material. The Mooney viscosity (ML _{1 +} 4/100 ° C.) of the modified polymer is preferably 10 to 1
50, more preferably 15 to 70. If the Mooney viscosity is less than 10, sufficient rubber properties such as abrasion properties cannot be obtained, and if it exceeds 150, workability is poor and it is difficult to knead with the compounding agent.

The rubber composition of the present invention must contain at least 30% by weight of the modified diene polymer as the rubber component (A). If this amount is less than 30% by weight, a rubber composition having desired physical properties cannot be obtained, and the object of the present invention cannot be achieved. The preferred content of the modified diene polymer in the rubber component is 35% by weight or more, and particularly preferably 40 to 100% by weight. This modified diene polymer may be used alone or in combination of two or more. Examples of the rubber component used in combination with the modified diene-based polymer include natural rubber and diene-based synthetic rubber. Examples of the diene-based synthetic rubber include styrene-butadiene copolymer (SBR) and polybutadiene (BR). , Polyisoprene (IR), butyl rubber (I
IR), ethylene-propylene copolymers, and mixtures thereof. Further, a part thereof may have a branched structure by using a polyfunctional modifier, for example, a modifier such as tin tetrachloride. In the rubber composition of the present invention, aluminum hydroxide powder is used as the component (B). The aluminum hydroxide powder has an average primary particle diameter D _I of 0.35 μm or less, an average secondary particle diameter D _L of 0.8 μm or less, and D _L / D _I.
Those having a ratio of 1.7 or less are preferably used. here,
Secondary particle average diameter D _L is the average size measured by a laser diffraction particle size analyzer after ultrasonic dispersion, an average primary particle diameter D _I, the following equation from the BET specific surface area

This is the diameter calculated by D _I = 6 / {(BET specific surface area) × (true specific gravity)}. (Note that the above BE
T specific surface area after drying at 110 ° C for 30 minutes, JIS R
This is a value measured by the nitrogen adsorption one-point method according to 1626. ) Or beyond the secondary particle average diameter D _L of the aluminum hydroxide powder is 0.8 [mu] m, an average primary particle diameter D _I 0.35
When the thickness exceeds μm, the reinforcing effect is not sufficiently exhibited, the wear resistance is poor, and the grip on wet road surface (wet performance).
May be reduced. On the other hand, if the particle diameter is too small, agglomeration between the particles becomes strong, and the ratio of secondary particle diameter / primary particle diameter (D _L / D _I ) exceeds 1.7, making it difficult to disperse well in rubber. In some cases, a rubber composition having desired performance cannot be obtained. Abrasion resistance, from the standpoint of wet performance and fuel economy of the balance, secondary particle average diameter D _L of the aluminum hydroxide powder is more preferably 0.5μm or less, an average primary particle diameter D _I is 0.30μm The following are more preferred. D _L / D _I is more preferably 1.5 or less.

In the present invention, the aluminum hydroxide powder of the component (B) may be used alone or in combination of two or more. The content is in the range of 3 to 60 parts by weight per 100 parts by weight of the component (A).
If the content is less than 3 parts by weight, sufficient grip on a wet road surface cannot be obtained, and the object of the present invention cannot be achieved. Also,
If the amount exceeds 60 parts by weight, abrasion resistance is impaired, and other physical properties required for the rubber composition may be reduced. Considering abrasion resistance, wet performance and fuel efficiency,
The preferred content of the component (B) is in the range of 5 to 40 parts by weight. In the rubber composition of the present invention, if desired, carbon black and / or silica powder can be blended as the component (C). Here, as the carbon black, channel black,
Furnace black, acetylene black, thermal black and the like can be used, and any of them can be used. This carbon black has a nitrogen adsorption specific surface area (BET) of 90 m ² / g or more and a dibutyl phthalate oil absorption (DBP) of 100 ml / g.
A weight of 100 g or more is preferred.

If the BET value is less than 90 m ² / g, it is difficult to obtain sufficient abrasion resistance, and if the BET value is too large, fuel economy may be deteriorated. In consideration of abrasion resistance and fuel economy, a more preferable range of the BET value is 90 to 300 m ² / g. The BET value is a value measured according to ASTM D3037-88. Further, the DBP value is 100 ml / 100 g.
If it is less than this, it is difficult to obtain sufficient wear resistance.
If the BP value is too large, fuel economy may be deteriorated. Considering abrasion resistance and low fuel consumption, this DBP
A more preferred range of values is 50-200 ml /
100 g. The DBP value is determined according to JIS K62
It is a value measured based on 21-1982 (A method).

On the other hand, the silica powder is not particularly limited, and may be appropriately selected from those conventionally used for reinforcing rubber, for example, dry silica and wet silica (hydrous silica). Although it is possible, wet process silica is preferred. This silica powder has a nitrogen adsorption specific surface area (BET) of 20 in consideration of wear resistance and low fuel consumption.
0-300 m ² / g and cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 170-27
Those in the range of 0 m ² / g are preferred. The B
The ET value was determined by ASTM D48 after drying at 300 ° C. for 1 hour.
It is a value measured according to 20-93, and the CTAB value is a value measured according to ASTM D3765-92. In the present invention, as the component (C) optionally used, only the carbon black may be used, only the silica powder may be used, or the carbon black and the silica powder may be used in combination. Is also good.
The content of the component (C) is 100 parts (A) in view of the balance between wear resistance, wet performance, and low fuel consumption.
The range is preferably from 5 to 85 parts by weight, particularly preferably from 30 to 70 parts by weight, per part by weight.

In the rubber composition of the present invention, (C)
When at least silica powder is used as a component,
To further improve its effect, if desired,
As the component (D), a coupling agent can be contained. There is no particular limitation on the coupling agent,
Any of various conventionally known coupling agents can be selected and used, and among them, a silane coupling agent is particularly preferable.

Here, examples of the silane-based coupling agent include the general formula (RO) ₃ Si—S _m —Si (OR) ₃ or XSI (OR) ₃ (where R is such that OR can be hydrolyzed) X is a functional group that reacts with an organic substance (for example, a mercaptoalkyl group, an aminoalkyl group, a vinyl group, an epoxy group,
Glycidoxyalkyl group, benzothiazolyl group, N, N
-Dimethylcarbamoyl group), and m is 0 <m ≦ 9
Is an integer that satisfies And a compound represented by the formula:
Specifically, bis (3-triethoxysilylpropyl)
Tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-methyldimethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, Screw (3-
Trimethoxysilylpropyl) disulfide, bis (3
-Triethoxysilylpropyl) trisulfide, 3-
Mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, γ- Glycidoxypropyltrimethoxysilane, γ
-Glycidoxypropylmethyldiethoxysilane, 3-
Examples include trimethoxysilylpropyl-N, N-dimethylcarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-trimethoxysilylpropylmethacryloylmonosulfide, and the like. In the present invention, the coupling agent of the component (D) optionally used may be used alone or in combination of two or more. The content is usually selected in the range of 1 to 20% by weight based on the silica powder of the component (C). If the content is less than 1% by weight, the effect of incorporating the coupling agent may not be sufficiently exerted, while if it exceeds 20% by weight, the effect is not improved in proportion to the amount, and the economy is rather increased. Disadvantageous. Considering the blending effect and economics,
The preferred content of the coupling agent of the component (D) is
It is in the range of 2 to 15% by weight.

The rubber composition of the present invention may contain various chemicals usually used in the rubber industry, such as a vulcanizing agent, a vulcanization accelerator, an antioxidant, as long as the object of the present invention is not impaired. Scorch inhibitor, softener, other filler, zinc white,
Stearic acid and the like can be contained. The rubber composition of the present invention is obtained by kneading using a kneading machine such as a roll and an internal mixer.After molding, vulcanization is performed, and a tire tread, an under tread,
It can be used not only for tire applications such as carcass, sidewalls and bead portions, but also for applications such as anti-vibration rubber, belts, hoses, and other industrial products, but is particularly suitably used as a rubber for tire treads.

The pneumatic tire of the present invention is produced by a usual method using the rubber composition of the present invention. That is, if necessary, the rubber composition of the present invention containing various chemicals as described above is extruded into a member for tread in an unvulcanized stage, and is pasted and molded by a normal method on a tire molding machine. Then, a green tire is formed. The green tire is heated and pressed in a vulcanizer to obtain a tire. The pneumatic tire of the present invention thus obtained retains wet performance and low fuel consumption, and also has good wear resistance.

[0051]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The physical properties of the vulcanized rubber were measured according to the following methods. (1) Wet skid performance (gripability on wet road surface) Using a spectrometer manufactured by Toyo Seiki Co., Ltd., a dynamic strain amplitude of 0.1%, a frequency of 52 Hz, and a measurement temperature of 0 ° C. were measured. The value of tan δ was expressed as an index with Comparative Example 1 being 100. The higher the value, the better. (2) Rolling resistance In (1) above, the reciprocal of the value of tan δ measured in the same manner except that the measurement temperature was changed to 60 ° C. was indicated as an index, with Comparative Example 1 being 100. The higher the value, the better. (3) Wear resistance Using a Lambourn-type abrasion tester, a slip ratio of 2 at room temperature was used.
The test was carried out under the condition of 5%, and the reciprocal of the amount of abrasion was represented by an index with Comparative Example 1 being 100. The higher the value, the better.

Production Example 1 300 g of cyclohexane, 40 g of 1,3-butadiene, 10 g of styrene, and 0.16 mmol of ditetrahydrofurylpropane were poured into an 800 ml pressure-resistant glass container which had been dried and purged with nitrogen. After adding 0.55 mmol of butyllithium (BuLi), the mixture was heated at 50 ° C.
For 2 hours. The polymerization system was uniformly transparent from the start to the end of the polymerization without any precipitation. The polymerization conversion was almost 100%. After 0.55 mmol of 3- (1-hexamethyleneimino) propyl (triethoxy) silane was further added as a terminal modifier to the polymerization system, a modification reaction was further performed for 30 minutes. Thereafter, 2,6-di-t-butyl-p-cresol (BH
0.5 ml of a 5% by weight solution of T) in isopropanol was added to stop the reaction, followed by drying according to a conventional method to obtain a modified SBR [A-1]. The weight average molecular weight of this modified SBR [A-1] is 26.8 × 1
0 ^4, a glass transition point of -37.0 ° C., Mooney viscosity [M
L _{1 +} 4/100 ° C.] was 25.0.

Production Example 2 In Production Example 1, instead of 3- (1-hexamethyleneimino) propyl (triethoxy) silane as a terminal modifier, N- (1,3-dimethylbutylidene) -3- was used.
Modified SBR [A-2] in the same manner as in Production Example 1 except that (triethoxysilyl) -1-propanamine was used.
I got This modified SBR [A-2] had a weight average molecular weight of 26.8 × 10 ⁴ , a glass transition point of −42.0 ° C., and a Mooney viscosity [ML _{1 +} 4/100 ° C.] of 32.0. Production Example 3 Production Example 1 is the same as Production Example 1 except that γ-glycidoxypropyltrimethoxysilane is used instead of 3- (1-hexamethyleneimino) propyl (triethoxy) silane as a terminal modifier. And modified SBR
[B] was obtained. This modified SBR [B] had a weight average molecular weight of 25.5 × 10 ⁴ , a glass transition point of -39 ° C., and a Mooney viscosity [ML _{1 +} 4/100 ° C.] of 30. Examples 1 and 2 and Comparative Examples 1 to 5 After the rubber compositions shown in Table 1 were prepared,
The composition was vulcanized under the condition of 0 minutes, and the physical properties of the obtained vulcanized rubber were measured. The results are shown in Table 1.

[0054]

[Table 1]

(Note) 1) SBR1500: Styrene butadiene rubber manufactured by JSR Co., Ltd. 2) Carbon black: manufactured by Tokai Carbon Co., Ltd., trade name "Seast KH", BET value 93 m ² / g, DB value 11
9 ml / 100 g 3) Silica powder: manufactured by Nippon Silica Industry Co., Ltd., trade name “Nip Seal AQ”, BET value 200 m ² / g, CTAB
Value: 145 m ² / g 4) Aluminum hydroxide powder: D _L 0.37 μm, D _I
0.30 μm, D _L / D _I 1.23 5) Silane coupling agent: Si69, bis (3-triethoxysilylpropyl) tetrasulfide manufactured by Degussa 6) Vulcanization accelerator DPG: diphenylguanidine 7) Antioxidant 6C: N- (1,3-dimethylbutyl)
-N'-phenyl-p-phenylenediamine

[0056]

The rubber composition according to the present invention uses an aluminum hydroxide powder as a reinforcing filler and a modified diene polymer having an enhanced interaction with aluminum hydroxide as a rubber component. In addition, it has good wet performance, low fuel consumption and abrasion resistance, and can reduce or eliminate the amount of the silane coupling agent, which is advantageous in terms of cost, and is particularly suitable as a rubber for tire tread. Used for

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/36 C08K 3/36 F term (Reference) 4J002 AC021 AC031 AC061 AC081 AC111 DA037 DE146 DJ017 FD016 FD017 GN01 4J100 AB00Q AB02Q AB03Q AB04Q AB16Q AS02P AS03P AS04P BA27H BA29H BA30H BA31H BA46H BA75H CA01 CA04 CA31 FA04 HA35 HA61 HC78 JA29

Claims (7)

[Claims] 1. A compound represented by the following general formula (I): (A) a polymerizable active terminal of a diene polymer. (Wherein, R ¹ and R ² each represent a monovalent hydrocarbon group having 1 to 18 carbon atoms, A ¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, and R ³ and R ⁴ each represent a non-valent hydrocarbon group. or substituted amino groups and / or ether groups to have even though good C1-18 monovalent hydrocarbon group, n is an integer from 1 to 3, when R ¹ O is more, each R ¹ O may be the same or different, and when there are a plurality of R ² , each R ² may be the same or different, and R ³ and R ⁴ may be the same or different. And R ³ and R ⁴ may be combined with each other to form a saturated or unsaturated ring structure together with the nitrogen atom to which R ³ and R ⁴ are attached.)
An aminohydrocarbyloxysilane compound represented by
Or the general formula (II) (Wherein, R ⁵ and R ⁶ are each a monovalent hydrocarbon group having 1 to 18 carbon atoms, A ² is a divalent hydrocarbon group having 1 to 20 carbon atoms, and R ⁷ and R ⁸ are each a hydrogen atom. An atom, or a monovalent hydrocarbon group having 1 to 18 carbon atoms which may have an unsubstituted or substituted amino group and / or an ether group;
3 of an integer, if R ⁵ O is more, each R ⁵ O may be the same as or different from each other, if R ⁶ is more, each R ⁶ may be the same with or different from each other. R ⁷ and R ⁸ may be the same or different from each other, and may be further bonded to each other to form a ring structure. A) a rubber component containing at least 30% by weight of a modified diene polymer obtained by reacting an imino group-containing hydrocarbyloxysilane compound represented by the formula (1), and (B) 3 to 60 parts by weight of aluminum hydroxide powder per 100 parts by weight of the rubber component A rubber composition comprising a part. 2. The rubber composition according to claim 1, further comprising 5 to 85 parts by weight of carbon black and / or silica powder as the component (C). 3. A diene polymer used as a raw material of the modified diene polymer in the component (A), wherein an organic lithium compound is used as a polymerization initiator, and a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound are polymerized. The rubber composition according to claim 1, wherein the rubber composition is obtained by the above method. 4. An aluminum hydroxide powder as the component (B)
Is the average primary particle diameter D _IIs less than 0.35μm and secondary particles
Average diameter D_LIs 0.8 μm or less, and D _L/ D_I
4. The method according to claim 1, wherein the ratio is not more than 1.7.
Rubber composition. 5. The carbon black as the component (C) has a nitrogen adsorption specific surface area (BET) of at least 90 m ² / g and a dibutyl phthalate oil absorption (DBP) of at least 100 ml / 100 g. 5. The rubber composition according to 3 or 4, above. 6. The silica powder of component (C) has a nitrogen adsorption specific surface area (BET) of 200 to 300 m ² / g and a cetyltrimethylammonium bromide adsorption specific surface area (CET).
5. The rubber composition according to claim ^{2, wherein} TAB) is from 170 to 270 m ² / g. 7. A pneumatic tire using the rubber composition according to any one of claims 1 to 6 as a tread rubber.