JP2001158836A - Rubber composition, oil-extended rubber and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition having excellent breaking characteristics, abrasion resistance, etc. SOLUTION: The rubber composition contains (A) 100 pts.wt. of a rubber component containing >=30 wt.% modified conjugated diene polymer produced by reacting an aminohydrocarbyloxysilane compound having a specific structure to a polymerization active terminal of a conjugated diene polymer, (B) 20-100 pts.wt. of an oil and (C) 60-150 pts.wt. of carbon black and/or silica.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition, an oil-extended rubber and a pneumatic tire. More specifically, the present invention relates to a rubber composition containing a large amount of a reinforcing filler and having excellent breaking characteristics and abrasion resistance, for example, as an application in which braking performance and steering stability on a wet road surface are important. The present invention relates to an oil-extended rubber that can be used for the rubber composition, and a pneumatic tire using the rubber composition.

[0002]

2. Description of the Related Art In recent years, with the increasing speed of automobiles, the characteristics required for tires have become stricter year by year, and various performances on wet road surfaces during high-speed running are mentioned as one of them. In order to improve braking performance and handling stability on wet road surfaces during high-speed running, grip performance on the road surface should be increased, and the block rigidity of the tire tread pattern should be increased, and the block during cornering should be improved. In addition to preventing deformation, improving cornering characteristics, preventing deformation of grooves formed in the tire tread, smoothly draining water, and preventing hydroplaning. In order to increase grip on wet road surfaces, it is important to compound a large amount of silica into the compounded rubber. It is known that when silica is compounded in a compounded rubber, a good frictional force on a wet road surface can be obtained by a surface effect. Further, in order to increase the grip force on the road surface, for example, a high-molecular weight styrene-butadiene copolymer rubber having excellent mechanical properties is mixed with a large amount of a reinforcing filler such as silica or carbon black. ing. In these cases, to improve workability,
It is necessary to mix more oil and the like than usual rubber compositions. However, there is a problem that when a large amount of oil or the like is blended, the fracture characteristics and wear resistance cannot be reduced.

On the other hand, in recent years, due to social demands for energy saving and environmental problems, attempts have been made to use materials having low heat generation as rubber compositions. In order to obtain the rubber composition having low heat build-up, many technical developments have been made so far to enhance the dispersibility of the 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.

[0004] As such a method, for example, a method in which carbon black is used as a filler and the polymerization active terminal is modified with a tin compound (Japanese Patent Publication No. 5-87530). (Japanese Patent Application Laid-Open No. 62-207342). Also, a method in which silica is used as a filler and the polymerization active terminal is modified with a silicon compound having an alkoxyl group (Japanese Patent Publication No. 6-57767, Japanese Patent Application Laid-Open No.
No. 33216, JP-A-9-87426) and the like. These methods are all techniques for improving the dispersibility of the filler and lowering the heat generation. However, the effect of sufficiently improving the fracture characteristics and abrasion resistance cannot be obtained with a high filler and a high oil content.

[0005]

SUMMARY OF THE INVENTION The present invention is intended for applications in which braking performance and steering stability on wet road surfaces and the like are emphasized in such a situation. It is an object of the present invention to provide a rubber composition having excellent properties and abrasion resistance, an oil-extended rubber which can be used for the rubber composition, and a pneumatic tire using the rubber composition.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, as a rubber component, a specific aminohydrocarbyloxy group was added to the polymerization active terminal of a conjugated diene polymer. By using a high-molecular-weight modified conjugated diene-based polymer obtained by reacting a silane compound, the dispersibility of the reinforcing filler is unexpectedly increased even if a large amount of the oil and the reinforcing filler are mixed. well,
It has been found that a rubber composition having excellent breaking characteristics and abrasion resistance can be obtained, and that a rubber composition containing a predetermined amount of oil can be used as an oil-extended rubber in the rubber composition. The present invention has been completed based on such findings. That is, the present invention provides (1) (A) a compound represented by the general formula (I),

[0007]

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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. A) a rubber component containing at least 30% by weight of a modified conjugated diene polymer having a weight average molecular weight of 400,000 or more obtained by reacting the aminohydrocarbyloxysilane compound represented by A rubber composition comprising (C) carbon black and / or silica (60 to 150 parts by weight);

(2) an oil-extended rubber characterized by containing the component (A) and 20 to 100 parts by weight of the component (B) per 100 parts by weight thereof; and (3) a tread rubber comprising the rubber composition. The present invention provides a pneumatic tire characterized in that it is used as a pneumatic tire.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the rubber composition of the present invention,
As the component (A), one containing a modified conjugated diene-based polymer is used. The modified conjugated diene-based polymer is obtained by modifying a conjugated diene-based polymer having one terminal as a polymerization active terminal with an aminohydrocarbyloxysilane compound having a specific structure. Such a conjugated diene polymer can be produced, for example, by using an organic lithium as a polymerization initiator and anionically polymerizing a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound. 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 can be mentioned. These may be used alone or in combination of two or more. Among them, 1,3-butadiene is particularly preferred.

Examples of aromatic vinyl compounds used for copolymerization with these conjugated diene compounds include styrene; α-methylstyrene; 1-vinylnaphthalene;
3-vinyltoluene; ethylvinylbenzene; divinylbenzene; 4-cyclohexylstyrene; 2,4,6-
Trimethylstyrene and the like. These may be used alone or in combination of two or more. Among 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, requires practical use such as easy availability of monomers, and anion. It is particularly preferable because the polymerization characteristics are excellent in terms of living properties and the like. As the organic lithium of the polymerization initiator, those having a hydrocarbyl group having 2 to 20 carbon atoms are preferable.
n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, Examples thereof include cyclohexyllithium, cyclopentyllithium, and reaction products of diisopropenylbenzene with butyllithium. Of these, n-butyllithium is preferable. Further, a lithium amide compound or the like may be used.

The method for producing a conjugated diene polymer by anionic polymerization using the above-mentioned organic lithium as a polymerization initiator is not particularly limited, and a conventionally known method can be used. Specifically, a conjugated diene compound or a conjugated diene compound and an aromatic vinyl compound are mixed in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound. Organic lithium as a polymerization initiator, if desired, by anionic polymerization in the presence of a randomizer used,
The desired conjugated diene polymer is obtained. The temperature in this polymerization reaction is usually -80 to 150 ° C, preferably -2.
It is selected in the range of 0 to 100 ° C. 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 conjugated diene-based polymer used as the rubber component is a conjugated polymer obtained as described above, having a hydrogen atom at one end and a polymerization active end at the other end. A general formula (I) is added to the polymerizable active terminal of the diene polymer.

[0014]

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It is obtained by reacting an aminohydrocarbyloxysilane 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,
Isopropyl group, n-butyl group, isobutyl group, sec
-Butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl, cyclopentyl, cyclohexyl, vinyl, propenyl,
Examples include an allyl group, a hexenyl group, an octenyl group, a cyclopentenyl group, and a cyclohexenyl group.

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. As this divalent hydrocarbon group,
For example, an alkylene group having 1 to 20 carbon atoms, 2 to 20 carbon atoms
, An arylene group having 6 to 20 carbon atoms, an aralkylene group having 7 to 20 carbon atoms, and the like. Of 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,
Examples include a pentamethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, and a dodecamethylene group.

[0017] n is an integer of 1 to 3, 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 is each independently But they may be different. 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. The monovalent hydrocarbon group having 1 to 18 carbon atoms is as described for R ¹ and R ² above;
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 dimethylaminomethyl group, 2-dimethylaminoethyl group, 3-dimethylaminopropyl group, p- Dimethylaminobenzyl, methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, p-methoxybenzyl, ethoxymethyl, 2-ethoxyethyl, 3-ethoxypropyl, p-ethoxybenzyl, etc. No. 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), the general formula (Ia)

[0018]

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(Wherein, R ⁵ and R ⁶ 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. But may be 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):

[0020]

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(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)
An alkylene group or alkenylene group of 20, R ¹ ,
R ² , A ¹ and n are the same as above. )) Are preferred. Examples of the cyclic amino group in the cyclic amino group-containing hydrocarbyloxysilane compound represented by the general formula (Ib) include, 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-
1-polymethyleneimino groups such as octadecamethyleneimino groups, further 1-imidazolyl groups, 4,5-dihydro-1-imidazolyl groups (2-imidazolin-1-yl groups), 1-imidazolidinyl groups, 1-piperazinyl Base,
Examples thereof include a morpholino group and a 4-oxazolin-3-yl group. Of these, a 1-hexamethyleneimino group and a 4,5-dihydro-1-imidazolyl group are preferred. Examples of the disubstituted amino group-containing hydrocarbyloxysilane compound represented by the general formula (Ia) include 3
-Dimethylaminopropyl (triethoxy) silane, 3
-Dimethylaminopropyl (trimethoxy) silane, 3
-Diethylaminopropyl (triethoxy) silane, 3
-Diethylaminopropyl (trimethoxy) silane, 2
-Dimethylaminoethyl (triethoxy) silane, 2-
Dimethylaminoethyl (trimethoxy) silane, 3-dimethylaminopropyl (diethoxy) methylsilane, 3
-Dibutylaminopropyl (triethoxy) silane and the like.

Examples of the cyclic amino group-containing hydrocarbyloxysilane compound represented by the general formula (Ib) include 3- (1-hexamethyleneimino) propyl (triethoxy) silane and 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. When reacting with the above-mentioned aminohydrocarbyloxysilane compound (hereinafter sometimes referred to as a terminal modifier) to the polymerization active terminal of the conjugated diene-based polymer, the amount of the terminal modifier used is conjugated diene-based polymer. It is usually from 0.25 to 3.0 mol per mol of the organolithium compound used for producing the polymer,
Preferably it is 0.5 to 1.5 mol. When 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. Also,
As the reaction temperature at this time, the polymerization temperature of the conjugated diene polymer can be used as it is. Specifically, 30-100
C is mentioned as a preferred 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 polymer are not particularly limited, but generally when such a terminal modifier is used,
It is often carried out after the end of polymerization. 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 this terminal modifier is reacted with the polymerization active terminal of the conjugated diene polymer, it is considered that a nucleophilic substitution product with hydrocarbyloxysilane is obtained as shown by the following formula (II). .

[0025]

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(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 (II) As shown, through the silicon atom, there will be both n-1 hydrocarbyloxy groups and a nitrogen-containing group. Among them, the hydrocarbyloxy group, when this modified conjugated diene polymer is blended with silica, the formula (III)

[0027]

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(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 silanol group which is a surface functional group of silica. . Therefore, in this case, n is preferably 2 or 3. The reason is that, when n is 1, the hydrocarbyloxy group is consumed for the nucleophilic substitution reaction to the terminal of the conjugated diene polymer, and is not present for the condensation reaction with the silanol group on the silica surface. This is because it is considered that no condensation reaction with the silanol group occurs. The synergistic effect of the condensation reaction with the silanol group and the interaction of the nitrogen-containing group with silica or carbon black can be expected to simultaneously provide the dispersing effect and the reinforcing effect of the filler.

When a cyclic amino group-containing hydrocarbyloxysilane compound is used among the terminal modifiers, a modified conjugated diene-based polymer exhibiting a good dispersing effect on both silica and carbon black can be obtained. In particular, when the conjugated diene polymer terminal is modified with an aminohydrocarbyloxysilane compound having a strongly basic dihydroimidazolyl group, such a highly basic functional group has an extremely strong interaction with both silica and carbon black. Thus, a modified conjugated diene-based polymer exhibiting the most excellent filler dispersing effect can be obtained. In the present invention, the modified conjugated diene-based polymer has a weight average molecular weight (Mw).
Is 400,000 or more. If this Mw is less than 400,000, the desired breaking characteristics and wear resistance cannot be obtained, and the object of the present invention cannot be achieved. Preferred Mw is 600,000 or more. In addition,
This Mw is a value in terms of polystyrene measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. The modified conjugated diene-based polymer preferably has a glass transition point (Tg) of -90 to -30C measured by a differential scanning calorimeter (DSC). -9 in the usual formulation of anionic polymerization
It is difficult to obtain a polymer below 0 ° C,
A polymer exceeding the above range becomes hard in a room temperature range, which is not preferable for use as a rubber-like elastic body. The rubber composition of the present invention needs to contain at least 30% by weight of the modified conjugated diene-based 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 conjugated diene-based polymer in the rubber component is 35% by weight or more, especially 40 to 100%.
% By weight is preferred.

The modified conjugated diene-based polymer may be used alone or in combination of two or more. Also,
Examples of rubber components used in combination with the modified conjugated diene-based polymer include natural rubber and diene-based synthetic rubber. Examples of the diene-based synthetic rubber include styrene-butadiene copolymer (SBR), polybutadiene (BR), Examples include polyisoprene (IR), butyl rubber (IIR), an ethylene-propylene copolymer, and a mixture 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, (B)
Oil is used as a component. As this oil,
There is no particular limitation, and any of those conventionally used as rubber extending oils can be appropriately selected and used. These oils are roughly classified into mineral oils, vegetable oils, and synthetic oils. In the present invention, mineral oils are preferably used. Examples of the mineral oils include petroleum process oils such as paraffinic process oils, naphthenic process oils, and aromatic process oils, polymerized high-boiling strong aromatic oils, liquid paraffin, and white oil. Of these, petroleum-based process oils, particularly aromatic-based process oils, are preferred.

In the present invention, the component (B) oil
Is 100 parts by weight of the rubber component (A).
Parts by weight are selected in the range of 20 to 100 parts by weight. This
If the amount is less than 20 parts by weight, the processability is poor, and 100 parts by weight
If it exceeds, the destruction characteristics will decrease. Of workability and fracture characteristics
From the viewpoint of balance, etc., the preferred blending of the component (B)
The amount is from 25 to 80 parts by weight, in particular from 30 to 70 parts by weight
Is preferable. Further, in the present invention, the above
100 parts by weight of the rubber component (A) is added to (B)
Mooney with 20 to 100 parts by weight of component oil
-Viscosity (ML_{1+ Four}/ 100 ° C) in the range of 20-100
Preferably, there is. If the Mooney viscosity is less than 20, it will break.
Breaking properties may be insufficient, and if it exceeds 100,
Workability deteriorates, which is not preferable. Fracture properties and workability
Mooney viscosity (ML)_{1 + 4}
/ 100 ° C.) is in the range of 30 to 80.
is there.

In the present invention, the component (B) oil may be added at the time of kneading when preparing the rubber composition, or may be added in advance to the rubber component (A) to prepare the oil. The oil-extended rubber may be used for preparing a rubber composition. In the rubber composition of the present invention,
As the component (C), carbon black and / or silica is used. The carbon black is not particularly limited, and any one can be selected from those conventionally used as a reinforcing filler for rubber. Examples of this carbon black include FEF, S
RF, HAF, ISAF, SAF and the like. Preferably, the carbon black has an iodine adsorption amount (IA) of 60 mg / g or more and a dibutyl phthalate oil absorption amount (DBP) of 80 ml / 100 g or more. By using this carbon black, the effect of improving various physical properties is increased, but in particular, HAF, I
SAF, SAF is preferred.

On the other hand, silica is not particularly limited, and it can be arbitrarily selected from those conventionally used as a reinforcing filler for rubber. Examples of the silica include wet silica (hydrous silicic acid), dry silica (silicic anhydride), calcium silicate, aluminum silicate, and the like. Remarkable wet silica is preferred.

In the present invention, as the reinforcing filler of the component (C), only carbon black may be used, only silica may be used, or a combination of carbon black and silica may be used. . The amount of the component (C) is selected in the range of 60 to 150 parts by weight based on 100 parts by weight of the rubber component (A). If this amount is less than 60 parts by weight, desired grip strength, breaking characteristics and abrasion resistance cannot be obtained, and if it exceeds 150 parts by weight, workability and the like deteriorate. Considering the physical properties and processability of the rubber composition, the preferred amount of the component (C) is 65%.
To 120 parts by weight, and particularly preferably in the range of 70 to 100 parts by weight.

In the present invention, when silica is used as the component (C), a silane coupling agent can be optionally added. The silane coupling agent is not particularly limited, and known silane coupling agents conventionally used in rubber compositions, for example, bis (3-triethoxysilylpropyl) polysulfide, γ-mercaptopropyltriethoxysilane, γ-aminopropyl Triethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, and the like can be used. The blending amount of the silane coupling agent optionally used is usually selected in the range of 1 to 20% by weight based on the silica of the component (C). If the amount is less than 1% by weight, the effect as a coupling agent is not sufficiently exhibited, and if it exceeds 20% by weight, gelation of the rubber component may be caused. From the viewpoints of the effect as a coupling agent and the prevention of gelation, the preferable amount of the silane coupling agent is in the range of 5 to 15% by weight.

The rubber composition of the present invention may contain, if desired, various chemicals usually used in the rubber industry, such as vulcanizing agents, vulcanization accelerators, antioxidants, as long as the object of the present invention is not impaired. An anti-scorch agent, zinc white, stearic acid and the like can be contained. Examples of the vulcanizing agent include sulfur, and the amount of the sulfur is preferably 0.1 to 10.0 parts by weight, more preferably 1.0 to 5.0 parts by weight, based on 100 parts by weight of the rubber component. 0 parts by weight. If the amount is less than 0.1 part by weight, the breaking strength and wear resistance of the vulcanized rubber may be reduced. If the amount exceeds 10.0 parts by weight, rubber elasticity may be lost. Although the vulcanization accelerator that can be used in the present invention is not particularly limited, for example, M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-2-benzothiazyl) Thiazoles such as sulfenamide) or DPG
(Diphenylguanidine) and other guadinine-based vulcanization accelerators.
The amount is preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 3.0 parts by weight, per 0 parts by weight.

The rubber composition of the present invention is obtained by kneading using a kneading machine such as a roll or an internal mixer. After molding, vulcanization is performed to obtain a tire tread, an undertread, a carcass and a side. It can be used not only for tire applications such as wall 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 present invention also provides an oil-extended rubber.
The oil-extended rubber of the present invention comprises the rubber component (A) and 100 to 100 parts by weight of the component (B) oil, preferably 25 to 80 parts by weight, per 100 parts by weight of the rubber component.
More preferably, it contains 30 to 70 parts by weight, and its Mooney viscosity (ML _{1 +} 4/100 ° C.) is preferably in the range of 20 to 100, particularly 30 to 80 for the above-mentioned reason. Is preferred.

The pneumatic tire of the present invention is manufactured 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 obtained in this manner has high gripping power, excellent breaking characteristics and abrasion resistance, and also has excellent processability of the rubber composition, and therefore has excellent productivity. ing.

[0039]

EXAMPLES 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 polymer were measured according to the following methods. <Physical Properties of Polymer> The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the polymer were measured by gel permeation chromatography [GPC: Tosoh HLC-8020,
Column: Tosoh GMH-XL (two in series)], and using a differential refractive index (R1), polystyrene conversion using monodisperse polystyrene as a standard. The Mooney viscosity of the polymer (after oil extension or non-oil extension) is RLM manufactured by Toyo Seiki Co., Ltd.
It measured at 100 degreeC using the -01 type tester. The microstructure of the butadiene portion of the polymer was determined by an infrared method (Morello method). The styrene unit content in the polymer is
^It was calculated from the integration ratio of the ¹ H-NMR spectrum. The glass transition point (Tg) of the polymer was measured using a differential scanning calorimeter (DSC) model 7 manufactured by Perkin Elmer Co., Ltd. after cooling to −100 ° C. and then increasing the temperature at 10 ° C./min. The physical properties of the vulcanized rubber were measured by the following methods, and the Mooney viscosity of the rubber composition was measured as described below.

<Physical Properties of Vulcanized Rubber> (1) Using a hysteresis loss viscoelasticity measuring device (manufactured by Rheometrics),
At a temperature of 50 ° C., a strain of 5% and a frequency of 15 Hz.
° C). The greater the tan δ (50 ° C.), the more hiss
High teresis loss. (2) Fracture characteristics Tensile stress at cutting (Tb) and 300% elongation
(M₃₀₀) Is measured according to JIS K6301-1995.
Specified. (3) Abrasion resistance Slip at room temperature using a Lambourn abrasion tester
Measure the amount of wear at a rate of 60% to determine the wear resistance of the control.
The index was expressed as an abrasion resistance index as 100. Exponent
Larger is better. <Mooney viscosity of rubber composition> JIS K6300-1
Mooney viscosity at 130 ° C [ML_{1+ Four}
/ 130 ° C].

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 a 800 ml pressure-resistant glass container which had been dried and purged with nitrogen. After adding 0.35 mmol of n-butyllithium (BuLi),
Polymerization was carried out for 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%. Sample a portion of the polymerization solution, add isopropyl alcohol, dry the solid,
A rubbery copolymer was obtained. The microstructure, molecular weight and molecular weight distribution of this copolymer were measured. The result is the first
It is shown in the table. In this polymerization system, 3-terminal as an unmodified modifier is further added.
After adding 0.35 mmol of (1-hexamethyleneimino) propyl (triethoxy) silane, a denaturation reaction was carried out for another 30 minutes. Thereafter, 0.5 ml of a 5% by weight solution of 2,6-di-t-butyl-p-cresol (BHT) in isopropanol was added to the polymerization system to stop the reaction, and then 18.75 g of aroma oil was added. The oil-extended polymer A was obtained by drying according to a conventional method. Table 1 shows the physical property values (Mooney viscosity and glass transition point before oil extension) of the obtained polymer.

Production Examples 2 to 6 In the same manner as in Production Example 1 except that the amount of n-butyllithium shown in Table 1 was used and the type and amount of the terminal modifier shown in Table 1 were used. Thus, a rubbery copolymer was obtained, and oil-extended polymers A to D and F and a non-oil-extended polymer E were produced. After completion of the polymerization, the polymer C was stopped without any modification reaction by adding 0.5 ml of a 5% by weight solution of 2,6-di-tert-butyl-p-cresol (BHT) in isopropanol. After that, 18.75 g of aroma oil was added, and dried by a conventional method. After the modification reaction, the polymer E
The reaction was terminated by adding 0.5 ml of a 5% by weight solution of isopropanol in the above, and dried by a conventional method without adding aroma oil. Table 1 shows the microstructure, molecular weight, and molecular weight distribution of each rubbery copolymer measured in the same manner as in Production Example 1, and Table 1 shows the physical properties of the polymers obtained therefrom.

[0043]

[Table 1]

(Note) Base Mw: molecular weight before denaturation reaction (Mw) Total Mw: molecular weight after denaturation reaction (Mw) Mw / Mn: molecular weight distribution after denaturation reaction HMIPT: 3- (1-hexamethyleneimino) propyl (Triethoxy) silane TEOSPDI: 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole TTC: tin tetrachloride DMAPES: 3-dimethylaminopropyl (diethoxy) methylsilane

Production Example 7 300 g of cyclohexane and 50 of 1,3-butadiene were placed in an 800 ml pressure-resistant glass container which had been dried and purged with nitrogen.
g and 1 mmol of tetrahydrofuran (THF) were added, and 0.35 mmol of n-butyllithium (BuLi) was added thereto, followed by polymerization 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%. A part of the polymerization solution was sampled, isopropyl alcohol was added, and the solid was dried to obtain a rubbery polymer. The microstructure, molecular weight and molecular weight distribution of this polymer were measured. Table 2 shows the results. 1- [3- (Triethoxysilyl) propyl] -4,5
After addition of 0.35 mmol of dihydroimidazole, a denaturation reaction was carried out for a further 30 minutes. Thereafter, 0.5 mL of a 5% by weight solution of BHT in isopropanol was added to the polymerization system to stop the reaction, and then aroma oil was added to the mixture.
The oil-extended polymer G was obtained by adding 75 g and further drying the polymer according to a conventional method. The physical properties of the obtained polymer are shown in Table 2.

Production Example 8 A rubbery polymer was obtained in the same manner as in Production Example 7, and the microstructure, molecular weight and molecular weight distribution of this polymer were measured.
Table 2 shows the results. After completion of the polymerization, the reaction was stopped by adding 0.5 ml of a 5 wt% solution of isopropanol of BHT without performing the denaturation reaction, and then 18.75 g of aroma oil was added, followed by drying according to a conventional method. The oil-extended polymer H was produced. The physical properties of the obtained polymer are shown in Table 2. Production Example 9 In Production Example 7, the amount of BuLi was changed from 0.35 mmol.
Production Example 7 was repeated except that the amount was changed to 0.55 mmol and the amount of 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole was changed from 0.35 mmol to 0.55 mmol. The same procedure was followed to carry out the polymerization and modification reactions. After completion of the denaturation reaction, 0.5 ml of a 5 wt% solution of BHT in isopropanol was added to stop the reaction, and the polymer I was obtained by drying according to a conventional method without adding aroma oil. For rubbery polymers,
Table 2 shows the microstructure, molecular weight, and molecular weight distribution measured in the same manner as in Production Example 7, and Table 2 shows the analytical values of the polymer obtained therefrom.

[0047]

[Table 2]

(Note) Base Mw, Total M
w, Mw / Mn and TEOSPDI are the same as the footnotes in Table 1.

Examples 1 to 3 and Comparative Examples 1 and 2 137.5 parts by weight of an oil-extended polymer (SBR) of the type shown in Table 3 obtained in Production Examples 1 to 4 and 6 (100 parts by weight of rubber component) , Aroma oil 37.5 parts by weight) and carbon black [manufactured by Tokai Carbon Co., Ltd., trademark: SEIST KH (N
339)] 20 parts by weight, silica [Nippon Silica Industry Co., Ltd.
Trade name: Nipsil AQ] 60 parts by weight, silane coupling agent [manufactured by Degussa, trademark: Si69, bis (3-triethoxysilylpropyl) tetrasulfide] 6 parts by weight, stearic acid 2 parts by weight, antioxidant 6C [N-
(1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine] to prepare a masterbatch, 3 parts by weight of zinc white, and a vulcanization accelerator DPG
(Diphenylguanidine) 1.0 part by weight, vulcanization accelerator DM
A rubber composition is prepared by blending 1 part by weight of (dibenzothiazyl disulfide), 1 part by weight of a vulcanization accelerator NS (Nt-butyl-2-benzothiazylsulfenamide) and 1.5 parts by weight of sulfur. did. The Mooney viscosity of the rubber composition was measured and vulcanized at 160 ° C. for 15 minutes, and the physical properties of the vulcanized rubber were measured. Table 3 shows the results.

Comparative Example 3 20 parts by weight of carbon black (supra), 60 parts by weight of silica (supra), and silane coupling with respect to 100 parts by weight of the non-oil-extended polymer E (SBR) obtained in Production Example 5 Agent "Si
69 "(described above), 6 parts by weight, aroma oil 37.5 parts by weight,
A master batch was prepared by mixing 2 parts by weight of stearic acid and 1 part by weight of an antioxidant 6C (described above),
Parts by weight, vulcanization accelerator DPG (described above) 1.0 part by weight, vulcanization accelerator DM (described above) 1 part by weight, vulcanization accelerator NS (described above) 1
Parts by weight and 1.5 parts by weight of sulfur were blended to prepare a rubber composition. While measuring the Mooney viscosity of the rubber composition,
The composition was vulcanized at 60 ° C. for 15 minutes, and the physical properties of the vulcanized rubber were measured. Table 3 shows the results.

[0051]

[Table 3]

(Note) The wear characteristics of Comparative Example 1 were 10
The exponent is set to 0. The above results were evaluated using an SBR base rubber as the modified rubber and a silica / carbon black mixed system as the filler. In Examples 1 to 3 of the present invention, rubber compositions excellent in fracture characteristics and wear characteristics were obtained as compared with Comparative Examples 1, 2, and 3. Examples 4 to 6 and Comparative Examples 4 and 5 137.5 parts by weight of an oil-extended polymer (SBR) of the type shown in Table 4 obtained in Production Examples 1 to 4 and 6 (100 parts by weight of rubber component, 37 parts of aroma oil 37 (1.5 parts by weight), 85 parts by weight of carbon black (described above), 2 parts by weight of stearic acid, and 1 part by weight of an antioxidant 6C (described above) were blended to prepare a master batch. Part, vulcanization accelerator DPG
0.5 parts by weight of the above-mentioned vulcanization accelerator, 0.5 parts by weight of the vulcanization accelerator DM, 0.5 parts by weight of the vulcanization accelerator NS, and 1.5 parts by weight of sulfur. A rubber composition was prepared. The Mooney viscosity of the rubber composition was measured and vulcanized at 160 ° C. for 15 minutes, and the physical properties of the vulcanized rubber were measured. Table 4 shows the results.

Comparative Example 6 85 parts by weight of carbon black (described above), 37.5 parts by weight of aroma oil, and 2 parts by weight of stearic acid based on 100 parts by weight of the non-oil-extended polymer E (SBR) obtained in Production Example 5 Parts and 1 part by weight of the antioxidant 6C (described above) were blended to prepare a masterbatch, and further 3 parts by weight of zinc white and a vulcanization accelerator DPG
0.5 parts by weight of the above-mentioned vulcanization accelerator, 0.5 parts by weight of the vulcanization accelerator DM, 0.5 parts by weight of the vulcanization accelerator NS, and 1.5 parts by weight of sulfur. A rubber composition was prepared. The Mooney viscosity of the rubber composition was measured and vulcanized at 160 ° C. for 15 minutes, and the physical properties of the vulcanized rubber were measured. Table 4 shows the results.

[0054]

[Table 4]

(Note) The wear characteristics of Comparative Example 4 were 10
The exponent is set to 0. The above results were obtained by using an SBR base rubber as the modified rubber and evaluating the carbon black as the filler. Embodiments 4 to 4 of the present invention
In No. 6, a rubber composition having excellent breaking characteristics and wear characteristics was obtained as compared with Comparative Examples 4, 5 and 6.

Example 7 and Comparative Example 7 96.25 parts by weight of an oil-extended polymer (BR) of the type shown in Table 5 obtained in Production Examples 7 and 8 (70 parts by weight of a rubber component, 26.25 parts of aroma oil) 100 parts by weight of a rubber component consisting of 30 parts by weight of natural rubber and 30 parts by weight of natural rubber, 40 parts by weight of carbon black (described above), 40 parts by weight of silica (described above), and a silane coupling agent "Si69" (described above). 4 parts by weight, 2 parts by weight of stearic acid, and 1 part by weight of an antioxidant 6C (described above) were blended to prepare a master batch.
0.8 parts by weight of vulcanization accelerator DPG (described above), DM of vulcanization accelerator
A rubber composition was prepared by blending 1 part by weight (described above), 1 part by weight of a vulcanization accelerator NS (described above), and 1.5 parts by weight of sulfur. Measure the Mooney viscosity of the rubber composition,
Vulcanization was carried out for 15 minutes, and the physical properties of the vulcanized rubber were measured.
Table 5 shows the results. Comparative Example 8 40 parts by weight of carbon black (described above) and silica were used for 100 parts by weight of a rubber component composed of 70 parts by weight of the non-oil-extended polymer I (BR) obtained in Production Example 9 and 30 parts by weight of natural rubber. (Supra) 40 parts by weight, silane coupling agent "Si6
9 "(described above) 4 parts by weight, aroma oil 26.25 parts by weight,
A master batch was prepared by mixing 2 parts by weight of stearic acid and 1 part by weight of an antioxidant 6C (described above),
Parts by weight, vulcanization accelerator DPG (described above) 0.8 part by weight, vulcanization accelerator DM (described above) 1 part by weight, vulcanization accelerator NS (described above) 1
Parts by weight and 1.5 parts by weight of sulfur were blended to prepare a rubber composition. While measuring the Mooney viscosity of the rubber composition,
The composition was vulcanized at 60 ° C. for 15 minutes, and the physical properties of the vulcanized rubber were measured. Table 5 shows the results.

[0057]

[Table 5]

(Note) The wear characteristics of Comparative Example 7 were 10
The exponent is set to 0. The above results were obtained by using a BR base rubber for the modified rubber and evaluating the silica / carbon black mixed system as the filler. The rubber composition of Example 7 of the present invention is superior to Comparative Examples 7 and 8 in breaking characteristics and wear characteristics.

[0059]

The rubber composition of the present invention is excellent in breaking characteristics and abrasion resistance. For example, the tread rubber composition of general-purpose tires and high-performance tires is important for braking performance and steering stability on wet road surfaces. It is suitably used for the intended use.

Claims (10)

[Claims] (A) A conjugated diene-based polymer having one terminal which is a polymerization active terminal has a general formula (I) (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.)
A rubber component containing at least 30% by weight of a modified conjugated diene polymer having a weight average molecular weight of 400,000 or more obtained by reacting an aminohydrocarbyloxysilane compound represented by the following formula: 10
A rubber composition comprising 0 parts by weight and (C) 60 to 150 parts by weight of carbon black and / or silica. 2. Component (B) is added to 100 parts by weight of component (A).
Mooney viscosity (ML when 0-100 parts by weight is added)
_{1 +} 4/100 ° C.) is in the range of 20-100.
The rubber composition as described in the above. 3. A conjugated diene-based polymer used as a raw material of the modified conjugated diene-based polymer in the component (A), wherein an organic lithium is used as a polymerization initiator, and a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound are used. 3. The rubber composition according to claim 1, which is obtained by polymerization. 4. The aminohydrocarbyloxysilane compound represented by the general formula (I) is a compound represented by the general formula (Ia): (Wherein, R ⁵ and R ⁶ 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, and they are the same or different. Wherein R ¹ , R ² , A ¹ and n are the same as described above.) 4. The rubber composition according to claim 1, wherein the compound is a disubstituted amino group-containing hydrocarbyloxysilane compound represented by the formula: object. 5. An aminohydrocarbyloxysilane compound represented by the general formula (I) is represented by the general formula (Ib): (In the formula, Q represents an alkylene group or alkenylene group having 2 to 20 carbon atoms which may be interrupted by at least one of a nitrogen atom and / or an oxygen atom, and R ¹ , R ² , A ¹ and n are the same as above. The rubber composition according to any one of claims 1 to 3, which is a cyclic amino group-containing hydrocarbyloxysilane compound represented by the following formula: 6. The rubber composition according to claim 5, wherein the cyclic amino group in the general formula (Ib) is a 1-hexamethyleneimino group or a 4,5-dihydro-1-imidazolyl group. 7. The modified conjugated diene-based copolymer in the component (A) has a glass transition point of -90 to -30 ° C. measured by a differential scanning calorimeter (DSC). 3. The rubber composition according to item 1. 8. (A) The conjugated diene-based polymer having one terminal being a polymerization active terminal has a compound represented by the general formula (I): (Wherein, R ¹ and R ² are each a monovalent hydrocarbon group having 1 to 18 carbon atoms, A ¹ is a divalent hydrocarbon having 1 to 20 carbon atoms, and R ³ and R ⁴ are each unsubstituted. Or 1 carbon atom which may have a substituted amino group and / or an ether group
~ 18 monovalent hydrocarbon group, n represents an integer of 1 to 3,
When there are a plurality of R ¹ O, each R ¹ O may be the same or different, and when there are a plurality of R ² , each R ³ may be the same or different. R ³ and R ⁴ may be the same or different from each other, and may be further bonded to each other to form a saturated or unsaturated ring structure together with the nitrogen atom to which R ³ and R ⁴ are bonded. A) a rubber component containing at least 30% by weight of a modified conjugated diene-based polymer having a weight average molecular weight of 400,000 or more obtained by reacting the aminohydrocarbyloxysilane compound represented by
Oil extended rubber comprising (B) 20 to 100 parts by weight of oil per 0 parts by weight. 9. The oil-extended rubber according to claim 8, wherein the Mooney viscosity (ML _{1 +} 4/100 ° C.) is in the range of 20 to 100. 10. A pneumatic tire using the rubber composition according to any one of claims 1 to 7 as a tread rubber.