JP2001131340A - Rubber composition and pneumatic tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition using silica as a reinforcing filler, having improved low heat build-up and processability, especially excellent fracture characteristics and abrasion resistance. SOLUTION: This rubber composition comprises (A) a rubber component containing >=30 wt.% of a modified conjugated diene-based polymer obtained by reacting a polymerization activity end of a conjugated diene-based polymer with an imino group-containing hydrocarbyloxysilane compound of specific structure and (B) 10-85 pts.wt. of silicic acid hydrate having 200-300 m2/g nitrogen adsorption ratio surface area (BET) and 170-270 m2/g cetyltrimethylammonium bromide adsorption specific surface area (CTAB) based on 100 pts.wt. of the rubber component.

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 has a good low heat build-up (low fuel consumption) and processability by using a modified conjugated diene-based polymer having an enhanced interaction with a reinforcing filler such as silica as a rubber component, and particularly, The present invention relates to a rubber composition having excellent breaking characteristics and abrasion resistance, and a pneumatic tire using the rubber composition.

[0002]

2. Description of the Related Art In recent years, demands for lowering fuel consumption of automobiles have become more severe in connection with the social demands for energy saving and the movement of global carbon dioxide emission regulations accompanying the growing interest in environmental issues. It is getting. In order to respond to such a demand, a reduction in rolling resistance has also been required for tire performance. As a method of reducing the rolling resistance of a tire, a method of optimizing a tire structure has been studied, but the use of a material having lower heat generation as the rubber composition is most commonly performed. In order to obtain such a rubber composition having a 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.

[0003] 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). However, these methods are effective when carbon black is used as the filler. By the way, in recent years, with increasing interest in the safety of automobiles, not only low fuel consumption performance, but also performance on wet road surfaces (hereinafter referred to as wet performance), particularly braking performance, has been increased. For this reason, the performance requirements for the rubber composition of the tire tread are not limited to simply reducing the rolling resistance, but those that highly satisfy both wet performance and low fuel consumption performance are required.

[0004] As a method of obtaining a rubber composition which simultaneously gives good fuel economy and good wet performance to a tire, carbon black, which has been generally used so far, has been used as a reinforcing filler. Thus, a method using silica such as hydrated silicic acid has already been performed. As described above, in the case of using the silica as a filler, as described above, the polymerization active terminal of the diene polymer obtained by anionic polymerization using an organolithium compound is modified with a functional group having an interaction with the silica. Attempts have been made to use such rubber materials. For example, a method in which silica is used as a filler and a 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.
233216, JP-A-9-87426) and the like. However, when using general hydrous silicic acid (wet process silica) widely used in the rubber industry at present as the silica, the above method is effective for obtaining a rubber composition having low heat generation and good processability. However, there has been a problem that the breaking characteristics and wear resistance are not always satisfactory.

[0005]

SUMMARY OF THE INVENTION Under such circumstances, the present invention uses silica as a reinforcing filler, and has good low heat build-up, wet performance and workability.
In particular, it is an object of the present invention to provide a rubber composition having excellent breaking characteristics and abrasion resistance, and a pneumatic tire using the rubber composition.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, as a rubber component, a specific imino group containing a specific imino group was added to the polymerization active terminal of the conjugated diene polymer. Using a rubber composition containing a modified conjugated diene-based polymer obtained by reacting a hydrocarbyloxysilane compound with a rubber composition containing a predetermined ratio of this rubber component and silica having a specific property, the inventors have found that the object can be achieved. Was. The present invention has been completed based on such findings. That is, the present invention relates to (A) a conjugated diene-based polymer having a hydrogen atom or a nitrogen-containing group at one terminal and the other terminal being a polymerization active terminal, the 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 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, n is an integer of 1 to 3, R ¹ O When there are two or more, each R ¹ O may be the same or different,
When there are a plurality of R ² , each R ² may be the same or different. R ³ and R ⁴ may be the same or different from each other, and may further be bonded to each other to form a ring structure. A) a rubber component containing at least 30% by weight of a modified conjugated diene-based polymer obtained by reacting an imino group-containing hydrocarbyloxysilane compound represented by the formula (I), and (B) a nitrogen adsorption specific surface area (BET) per 100 parts by weight thereof. 200-300 m ² / g and cetyltrimethylammonium bromide adsorption specific surface area (CTA
B) The hydrated silicic acid 10 to 170 to 270 m ² / g
85 parts by weight, and optionally 1 to 20% by weight of the (C) silane coupling agent and / or 80 parts by weight of (D) carbon black per 100 parts by weight of the above component (A). The present invention provides a rubber composition comprising:

[0009] The present invention also provides a pneumatic tire using the rubber composition as a tread rubber.

[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 has a hydrogen atom or a nitrogen-containing group at one end, and a conjugated diene-based polymer having the other end as a polymerization active end, and an imino group-containing hydrocarbyloxysilane compound having a specific structure. And denatured. Such a conjugated diene polymer can be produced, for example, by using an organic lithium compound as a polymerization initiator and anionically polymerizing the conjugated diene compound alone or the conjugated diene compound and an aromatic vinyl compound. Examples of the conjugated diene compound include 1,3-butadiene; isoprene; 1,3-pentadiene;
-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 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, 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, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium
reaction products of tert-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butyl-phenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclopentyllithium, diisopropenylbenzene and butyllithium Among them, n-butyllithium is preferable.

On the other hand, lithium amide compounds include, for example, lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethyl amide, lithium diethyl amide, lithium dibutyl amide, lithium dipropyl Amide, lithium diheptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide _, lithium-N-methylpiperazide, lithium ethylpropylamide, lithium ethylbutylamide _, lithium methylbutylamide, lithium ethyl Benzylamide, lithium methylphenethylamide and the like. Among these, lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide,
Cyclic lithium amides such as lithium heptamethyleneimide and lithium dodecamethyleneimide are preferred, and lithium hexamethyleneimide and lithium pyrrolidide are particularly preferred.

The method for producing a conjugated diene polymer by anionic polymerization using the above-mentioned organolithium compound 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. 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 conjugated diene-based polymer used as a rubber component has a hydrogen atom or a nitrogen-containing group at one end and a polymerization active at the other end obtained as described above. A terminal of the general formula (I) is added to the polymerization active end of the conjugated diene polymer as a terminal.

[0016]

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By reacting an imino group-containing hydrocarbyloxysilane compound represented by the 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 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 group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group and 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.

[0019] 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 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 above, and R ³ and R ⁴ are an unsubstituted or substituted amino group or an ether group or both. May be provided. R ³ and R ⁴ may be the same or different from each other, and may further be bonded to each other to form a ring structure. This ring structure may be a saturated or unsaturated hydrocarbon ring structure, or may be a saturated or unsaturated heterocyclic structure having a nitrogen atom and / or an oxygen atom as a hetero atom.

In the general formula (I), the imino group bonded to A ¹ includes, for example, an ethylideneamino group;
Methylpropylideneamino group; 1,3-dimethylbutylideneamino group; 1-methylethylideneamino group; 4-
N, N-dimethylaminobenzylideneamino group; cyclohexylideneamino group and the like can be preferably mentioned. Examples of the imino group-containing hydrocarbyloxysilane compound represented by the general formula (I) 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 compounds, methyldiethoxysilyl compounds, ethyldiethoxysilyl compounds, methyldimethoxysilyl compounds, ethyldimethoxysilyl compounds and the like corresponding to these triethoxysilyl compounds are preferred. Among them, N- (1-methylpropylidene) -3- (triethoxysilyl) -1-propanamine and N- (1,
3-Dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine is preferred.

The above imide group-containing hydrocarbyloxysilane compound (hereinafter sometimes referred to as a terminal modifier).
When using to react with the polymerization active terminal of the conjugated diene-based polymer, the amount of the terminal modifier used is, based on 1 mol of the organolithium compound used in the production of the conjugated diene-based polymer,
It is usually from 0.25 to 3.0 mol, preferably from 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. The reaction temperature at this time is
The polymerization temperature of the conjugated diene polymer can be used as it is. 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 terminal modifier to the conjugated diene polymer at the polymerization active terminal are not particularly limited, but generally when such 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). The terminal modifier used in the present invention has a methyleneamino group in the molecule as shown by the general formula (I), and this methyleneamino group has the same basic basicity as the tertiary amino group. In addition, the compound has little steric hindrance, and thus easily exhibits various acidic functional groups and good hydrogen bonding force. When this terminal modifier is reacted with the polymerization active terminal of the conjugated diene-based polymer, as shown in the following formula (II), the nucleophilic substitution product with hydrocarbyloxysilane and the addition to the methyleneamino group It is believed that a mixture of reaction products is obtained. That is, when a nucleophilic substitution reaction is carried out on the polymerization active terminal of the polymer, an interaction is generated between the acidic functional group on the silica surface and the introduced methyleneamino group, and a good silica dispersion effect and a reinforcing effect are simultaneously obtained. Can be expected to give. Also, when added to the polymerization active terminal of the polymer, it is converted to a secondary amine. Even in such a case, good silica dispersibility can be expected due to the secondary amine having a high hydrogen bond with the silanol group.

[0023]

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(The formulas, R ^{1 to} R ⁴ , A ¹ and n are the same as described above.) Further, the terminal modifier has a hydrocarbyloxysilyl group, and is provided at the polymerization active terminal of the polymer. The introduced hydrocarbyloxysilyl group undergoes a condensation reaction with a silanol group on the surface of the silica, thereby providing an extremely high reinforcing effect due to a synergistic effect with the hydrogen bonding force of the methyleneamino group. When the imino group bonded to A ¹ is an N, N-dimethylaminobenzylideneamino group, if carbon black is used together with silica as a filler, a stronger interaction with carbon black will result in a better reinforcing effect. Can be obtained. By the above, this modified conjugated diene polymer is blended with silica,
In addition, it is possible to obtain good reinforcing properties in a mixture of silica and carbon black, and to provide a rubber composition having excellent wear properties and breaking properties.

The modified conjugated diene polymer 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) of the modified polymer
_{(1 + 4} , 100 ° C.) is preferably from 10 to 150, more preferably from 15 to 70. If the Mooney viscosity is less than 10, sufficient rubber properties such as breaking characteristics cannot be obtained, and if it exceeds 150, workability is poor and it is difficult to knead the compound with the compounding agent. 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, and particularly preferably 40 to 100% by weight.

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)
Hydrous silicic acid is used as a component. In the present invention, the hydrous silicic acid has a nitrogen adsorption specific surface area (BET) of 20.
0-300 m ² / g and cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 170-27
A hydrous silicic acid of 0 m ² / g is used.

The hydrated silicic acid having such properties is finer in particle size and larger in surface area than the commonly used hydrated silicic acid, and is different from the modified conjugated diene polymer in the component (A). Since the number of reaction sites increases, the effect of improving fracture characteristics and wear resistance is brought about. The BET is 200 m ² /
When the CTAB is less than 170 m ² / g or when the CTAB is less than 170 m ² / g, the effect of improving the breaking characteristics and wear resistance is not sufficiently exhibited. In addition, the BET exceeds 300 m ² / g, or CTAB
If it exceeds 270 m ² / g, the cohesive force of the hydrated silicic acid becomes too strong, causing poor dispersion in the rubber composition, and the fracture characteristics and abrasion resistance are rather lowered, and the processability is also lowered. Considering the fracture characteristics, wear resistance and workability,
The preferred BET of this hydrous silicic acid is 220 to 260 m ^2.
/ G, while the preferred CTAB is between 180 and 2
It is in the range of 30 m ² / g.

In the present invention, the hydrous silicic acid of the component (B) is blended in an amount of 10 to 85 parts by weight based on 100 parts by weight of the rubber component of the component (A). This amount is 1
If the amount is less than 0 parts by weight, the effect of improving reinforcing properties and other physical properties is not sufficiently exhibited, and if it exceeds 85 parts by weight, workability and the like are reduced. In consideration of reinforcing properties, other physical properties and workability, the amount of the hydrous silicic acid is preferably in the range of 20 to 60 parts by weight. In the rubber composition of the present invention, if desired, a silane coupling agent can be blended as the component (C). As this silane coupling agent,
There is no particular limitation, and known ones conventionally used in rubber compositions, such as bis (3-triethoxysilylpropyl) polysulfide, γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane,
N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane and the like can be used. The compounding amount of the silane coupling agent optionally used is usually 1 to 20% by weight based on the hydrous silicic acid of the component (B).
Is selected in the range. When the amount is less than 1% by weight, the effect as a coupling agent is hardly 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.

Further, in the rubber composition of the present invention,
If desired, carbon black can be used as the component (D) together with the silica for the purpose of improving the storage elastic modulus and the reinforcing property. 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 the carbon black include FEF, SRF, HAF, ISAF, SAF and the like. Preferably, the iodine adsorption amount (IA) is 60 mg / g.
This is carbon black having a dibutyl phthalate oil absorption (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, ISAF, and SAF, which are excellent in wear resistance, are preferable. In the present invention, the compounding amount of the optional component (D) carbon black is set to be in a range of 80 parts by weight or less based on 100 parts by weight of the component (A) and the component (B). Is preferably selected so that the total amount thereof with the hydrous silicic acid is 120 parts by weight or less. If the compounding amount of the carbon black exceeds 80 parts by weight or the total amount with the component (B) exceeds 120 parts by weight, it is difficult to obtain a rubber composition having desired physical properties, and the object of the present invention cannot be achieved. There is a risk. From the viewpoints of the blending effect and the physical properties, the preferred blending amount of the component (D) is in the range of 5 to 70 parts by weight, and the total blended amount with the component (B) is preferably 100 parts by weight or less.

The rubber composition of the present invention may optionally contain various chemicals usually used in the rubber industry, such as vulcanizing agents, vulcanization accelerators, process oils, aging, as long as the objects of the present invention are not impaired. Inhibitors, scorch inhibitors, zinc white, stearic acid and the like can be contained. Examples of the vulcanizing agent include sulfur and the like.
The sulfur content is preferably 0.1 to 10.0 parts by weight, more preferably 1.0 to 5.0 parts by weight, based on parts by weight. 0.1
If the amount is less than 10 parts by weight, the fracture strength, abrasion resistance, and low heat build-up of the vulcanized rubber may be reduced. If the amount exceeds 10 parts by weight, rubber elasticity may be lost. The vulcanization accelerator that can be used in the present invention is not particularly limited.
(2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-
Thiazole-based vulcanization accelerators such as 2-benzothiazylsulfenamide) or guanidine-based vulcanization accelerators such as DPG (diphenylguanidine) can be used. The amount is preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 3.0 parts by weight. Examples of the process oil that can be used in the rubber composition of the present invention include, for example, paraffinic, naphthenic, and aromatic oils. An aromatic type is used for applications where importance is placed on tensile strength and wear resistance, and a naphthene type or paraffin type is used for applications where importance is attached to hysteresis loss and low-temperature characteristics. The amount of the rubber component is preferably 0 to 100 parts by weight based on 100 parts by weight of the rubber component, and if it exceeds 100 parts by weight, the tensile strength and low heat buildup of the vulcanized rubber tend to deteriorate.

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 carried out to obtain a tire tread, undertread, carcass, and 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 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 way has good fuel economy and is particularly excellent in fracture characteristics and wear resistance.
In addition, the processability of the rubber composition is good, so that the productivity is also excellent.

[0032]

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 was measured at 100 ° C. using an RLM-01 tester manufactured by Toyo Seiki. The microstructure of the butadiene portion of the polymer was determined by an infrared method (Morello method). The styrene unit content in the polymer was calculated from the integral ratio of the ¹ H-NMR spectrum. Glass transition point (Tg) of polymer
Is a differential scanning calorimeter (DSC) manufactured by PerkinElmer
10 ° C / m after cooling to -100 ° C using a 7-type device
The measurement was performed under the condition of increasing the temperature in. 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) Low heat build-up Using a viscoelasticity measuring device (manufactured by Rheometrics),
At a temperature of 50 ° C., a strain of 5% and a frequency of 15 Hz.
° C). The lower the tan δ (50 ° C), the lower the emission
It is feverish. (2) Rebound resilience Measured by Dunlop trypsometer (BS903)
The temperature was measured at 25 ° C. (3) Fracture properties Strength at break (Tb) and at 100% and 300% elongation
Tensile stress (M₁₀₀, M ₃₀₀) To JIS K6301-1
995. (4) 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].

<Characteristics of hydrous silicic acid> (1) Measurement of BET Am. Chem. Soc. 60, p. 309 (1
938), a fully automatic specific surface area measuring device beta 423 manufactured by Micro Data Co., Ltd.
It was measured by a one-point method using a type 2. (2) Measurement of CTAB The measurement was performed according to the method described in ASTM D3765-92. However, since the method described in ASTM D3765-92 is a method for measuring the CTAB of carbon black, the method was slightly modified. That is, carbon black standard IRB # 3 (83.0 m ² /
g) was not used, and a standard solution of cetyltrimethylammonium bromide (hereinafter, abbreviated as CE-TRAB) was prepared separately, thereby standardizing the hydrous silicate OT (sodium di-2-ethylhexylsulfosuccinate) solution. The specific surface area was calculated from the adsorption amount of CE-TRAB, assuming that the adsorption cross-sectional area per molecule of CE-TRAB to the hydrous silicic acid surface was 0.35 nm ² . This is because carbon black and hydrous silicic acid have different surfaces, and therefore it is considered that there is a difference in the amount of CE-TRAB adsorbed even with the same surface area.

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 addition of 0.55 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, N-terminal
After adding 0.55 mmol of (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, a denaturation reaction was carried out for another 30 minutes. Thereafter, 2,6-di-tert-butyl-p-cresol (B
The reaction was stopped by adding 0.5 ml of a 5% by weight solution of HT) in isopropanol, and the polymer A was obtained by drying according to a conventional method. The analytical values of the obtained polymer are shown in Table 1.

Production Examples 2 to 5 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 polymers B to E were produced. The polymer E
After completion of polymerization, 2,6-di-t
The reaction was terminated by adding 0.5 ml of a 5% by weight solution of -butyl-p-cresol (BHT) in isopropanol, followed by drying according to a conventional method. 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 analysis values of the polymers obtained therefrom.

Production Example 6 300 g of cyclohexane and 40 g of 1,3-butadiene 40 were placed in an 800 ml pressure-resistant glass container dried and purged with nitrogen.
g, styrene 10 g, ditetrahydrofurylpropane 0.
16 mmol was injected, and n-butyllithium (B
After adding 0.55 mmol of uLi), 0.5 mmol of hexamethyleneimine was quickly added, and polymerization was carried out at 50 ° C. for 1.5 hours. The polymerization system was uniformly transparent from the start to the end of the polymerization without any precipitation. The polymerization conversion is approximately 1
00%. 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 1 shows the results.
Next, a modification reaction was carried out in the same manner as in Production Example 1 to obtain a polymer F
I got The analytical values of the obtained polymer are shown in Table 1.

Production Example 7 Polymerization was carried out in the same manner as in Production Example 6, except that the amount of BuLi was changed to 0.45 mmol and the amount of hexamethyleneimine was changed to 0.4 mmol. The polymerization system was uniformly transparent without any precipitation from the start to the end of the polymerization. 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 copolymer. The microstructure, molecular weight and molecular weight distribution of this copolymer were measured. Table 1 shows the results. After completion of the polymerization, a 5 wt% solution of BHT in isopropanol was
The reaction was stopped by adding 5 ml, and the polymer G was dried by a conventional method. The analytical values of the obtained polymer are shown in Table 1.

[0039]

[Table 1]

(Note) BaseMw: molecular weight before denaturation reaction (Mw) TotalMw: molecular weight after denaturation reaction (Mw) Mw / Mn: molecular weight distribution after denaturation reaction DMBTESPA: N- (1,3-dimethylbutylidene)- 3- (triethoxysilyl) -1-propanamine METESPA: N- (1-methylethylidene)-
3- (triethoxysilyl) -1-propanamine DMBTMSPA: N- (1,3-dimethylbutylidene) -3- (trimethoxysilyl) -1-propanamine TTC: tin tetrachloride

Production Example 8 300 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 0.55 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. After further adding 0.55 mmol of N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine to the polymerization system, a modification reaction was carried out for 30 minutes. Thereafter, a 5% by weight solution of BHT in isopropanol 0.5 was added to the polymerization system.
The reaction was stopped by adding milliliters, and the polymer was dried by a conventional method to obtain a polymer H. The analytical values of the obtained polymer are shown in Table 2.

Production Example 9 A rubbery polymer was obtained in the same manner as in Production Example 8, 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% by weight solution of BHT in isopropanol without performing a denaturation reaction, and then dried according to a conventional method to obtain a polymer I. The analytical values of the obtained polymer are shown in Table 2.

[0043]

[Table 2]

(Note) BaseMw, TotalMw, M
w / Mn and DMBTESPA are the same as footnotes in Table 1. Table 3 shows the properties of the hydrous silicic acid used in the examples and comparative examples.

[0045]

[Table 3]

(Note) 1) AQ: Nipsil A (trade name, manufactured by Nippon Silica Industry Co., Ltd.)
Q ”2) KQ: Nipsil K, manufactured by Nippon Silica Industry Co., Ltd.
Q) 3) PR: Tokuyama Co., Ltd., trademark “TOXIR PR” 4) H2000: PPG Industries, In
c. Examples: 1 to 6 and Comparative Examples 1 to 12 Polymers of the type shown in Table 4 obtained in Production Examples 1 to 7 (SB
R) 55 parts by weight of hydrated silicic acid of the type shown in Table 4 and 100 parts by weight of silane coupling agent "Si69" (trade name: bis (3-triethoxysilylpropyl) tetrasulfide manufactured by Degussa) 5. 5 parts by weight, aroma oil 10
Parts by weight, stearic acid 2 parts by weight, antioxidant 6C [N-
(1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine] to prepare a master batch, 3 parts by weight of zinc white, and vulcanization accelerator DPG
(Diphenylguanidine) 1 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 4 shows the results.

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

[Table 6]

The wear characteristics are indicated by an index with the value of Comparative Example 5 set to 100. The above results show that the modified rubber has SBR
The base rubber was used, and the filler was evaluated as silica. Examples 1 to 6 in the present invention are Comparative Examples 1 to
As compared with No. 12, a rubber composition having more excellent breaking characteristics and wear characteristics was obtained. In addition, in the comparative example, when KQ silica was used as compared with AQ silica, tan δ was low, but this was because G ′ was high due to poor dispersibility, and the rebound resilience was low (low heat buildup was low). become worse. But,
In Examples, by using a modified polymer, the effect of greatly improving the dispersibility and increasing the rebound resilience (better low heat generation) can be obtained. Further, in the comparative example,
With KQ silica compared to AQ silica, M _{10 0} is increased, this is harder insufficient dispersibility, M
₃₀₀ drops. However, in the embodiment, by using the modified polymer, to improve the reinforcing property, the effect is obtained that higher M _300. Example 7 and Comparative Examples 13 to 15 The polymers shown in Table 5 obtained in Production Examples 1 and 5 (SB
R) 27 parts by weight of carbon black [manufactured by Tokai Carbon Co., Ltd., trade name: Seast KH (N339)] for 100 parts by weight of a rubber component consisting of 70 parts by weight of natural rubber and 30 parts by weight of natural rubber, of the type shown in Table 5 27 parts by weight of hydrous silicic acid, 10 parts by weight of aroma oil, 2 parts by weight of stearic acid, 1 part by weight of antioxidant 6C (described above) are blended to prepare a master batch, and 3 parts by weight of zinc white and vulcanization acceleration Agent DPG (see above)
0.8 parts by weight, 1 part by weight of a vulcanization accelerator DM (described above), 1 part by weight of a vulcanization accelerator NS (described above), and 2.5 parts by weight of sulfur were blended to prepare a rubber composition. Measure the Mooney viscosity of the rubber composition, and vulcanize at 160 ° C. for 15 minutes.
The physical properties of the vulcanized rubber were measured. Table 5 shows the results.

[0051]

[Table 7]

(Note) The wear characteristics of Comparative Example 14 were 1
The exponent is set to 00. The above results were evaluated using an SBR base rubber as the modified rubber and a silica / carbon black mixed system (without adding a silane coupling agent) as the filler. The rubber composition of Example 7 of the present invention is superior in the breaking characteristics and the wear characteristics as compared with Comparative Examples 13 to 15. In the comparative example, AQ
When KQ silica is used as compared with silica, tan δ becomes low, but this is because G ′ becomes high due to poor dispersibility, and the rebound resilience becomes low (low heat build-up is poor). However, in the examples, by using the modified polymer, the effect of greatly improving the dispersibility and increasing the rebound resilience (low heat generation) can be obtained. Further, in the comparative example, the use of KQ silica compared to AQ silica, M _{10 0}
Is high, but this is due to insufficient dispersibility and hardness, and M ₃₀₀ is lowered. However, in the examples, by using a modified polymer, the reinforcing property was improved and M
_The effect of increasing ₃₀₀ is obtained. Example 8 and Comparative Examples 16 to 18 With respect to 100 parts by weight of a rubber component comprising 70 parts by weight of the polymer (SBR) shown in Table 6 and 30 parts by weight of natural rubber obtained in Production Examples 1 and 5, 27 parts by weight of carbon black (supra), 27 parts by weight of hydrous silicic acid of the type shown in Table 6, and a silane coupling agent "Si69" (supra) 2.5
Parts by weight, 10 parts by weight of aroma oil, 2 parts by weight of stearic acid, and 1 part by weight of antioxidant 6C (described above) to prepare a masterbatch, and further 3 parts by weight of zinc white and DPG (vulcanization accelerator Ex) 0.8 parts by weight, vulcanization accelerator DM (supra) 1
Parts by weight, 1 part by weight of a vulcanization accelerator NS (described above) and 1.5 parts of sulfur
A rubber composition was prepared by blending parts by weight. 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 6 shows the results.

[0053]

[Table 8] The abrasion resistance is indicated by an index with the value of Comparative Example 17 being 100. The above results were evaluated using an SBR base rubber as the modified rubber and a silica / carbon black mixed system (with a silane coupling agent) as the filler.
The rubber compositions of Example 8 in the present invention were prepared in Comparative Examples 16 to
Compared with No. 18, it is excellent in breaking characteristics and wear characteristics. Further, in the comparative example, KQ was larger than AQ silica.
When silica is used, tan δ decreases, but G ′ increases due to poor dispersibility, and the rebound resilience decreases (low heat build-up decreases). However, in the examples, by using the modified polymer, the effect of greatly improving the dispersibility and increasing the rebound resilience (low heat generation) can be obtained. Further, in the comparative example, the use of KQ silica compared to AQ silica, M _{10 0} is increased, this is harder insufficient dispersibility, M ₃₀₀ decreases. However, in the embodiment, by using the modified polymer, to improve the reinforcing property, the effect is obtained that higher M _300. Example 9 and Comparative Examples 19-21 Based on 100 parts by weight of a rubber component comprising 70 parts by weight of the polymer (BR) shown in Table 7 and 30 parts by weight of natural rubber obtained in Production Examples 8 and 9, Carbon black (see above)
27 parts by weight, 27 parts by weight of hydrous silicic acid of the type shown in Table 7, 2.5 parts by weight of silane coupling agent "Si69" (described above), 10 parts by weight of aroma oil, 2 parts by weight of stearic acid, antioxidant A master batch was prepared by mixing 1 part by weight of 6C (described above), 3 parts by weight of zinc white, 0.8 parts by weight of vulcanization accelerator DPG (described above), and 1 part by weight of vulcanization accelerator DM (described above).
Parts by weight, 1 part by weight of a vulcanization accelerator NS (described above) and 1.5 parts of sulfur
A rubber composition was prepared by blending parts by weight. 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 7 shows the results.

[0054]

[Table 9]

(Note) The abrasion resistance of Comparative Example 20 was 1
The exponent is set to 00. 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 9 in the present invention is superior in the breaking characteristics and the abrasion characteristics as compared with Comparative Examples 19 to 21. Also,
In the comparative example, when KQ silica is used as compared with AQ silica, tan δ becomes low, but this is because G ′ becomes high due to poor dispersibility, and the rebound resilience is low (low heat build-up is poor). Become. However, in the examples, by using the modified polymer, the effect of greatly improving the dispersibility and increasing the rebound resilience (low heat generation) can be obtained.
Further, in the comparative example, the use of KQ silica compared to AQ silica, M ₁₀₀ is high, this is harder insufficient dispersibility, M ₃₀₀ decreases. But,
In embodiments, the use of the modified polymer, to improve the reinforcing property, the effect is obtained that higher M _300.

[0056]

According to the rubber composition of the present invention, a modified conjugated diene polymer having a high interaction with hydrated silicic acid as a rubber component is used as a rubber filler. It is used and has good low heat build-up, good wet performance and workability, and particularly excellent breakage characteristics and wear resistance, and is suitable for use in tire tread rubber.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 3/04 C08K 3/04 3/34 3/34 5/541 5/541 F term (Reference) 4J002 AC111 DA038 DJ006 EX037 EX077 EX087 GN01 4J015 DA02 4J100 AB00Q AB02Q AB03Q AB04Q AB07Q AB16Q AS02P AS03P AS04P AS06P BA46H BA75H BC04Q BC43P CA01 CA04 FA08 HA61 HC77 JA29

Claims (10)

[Claims] (A) A conjugated diene-based polymer having a hydrogen atom or a nitrogen-containing group at one terminal and the other terminal being a polymerization active terminal has a compound represented by the general formula (I): Formula 1 (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 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;
Shows three integer, if 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 be bonded to each other to form a ring structure. A) a rubber component containing at least 30% by weight of a modified conjugated diene-based polymer obtained by reacting an imino group-containing hydrocarbyloxysilane compound represented by the formula (I), and (B) a nitrogen adsorption specific surface area (BET) per 100 parts by weight thereof. 20
0-300 m ² / g and cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 170-27
A rubber composition comprising 10 to 85 parts by weight of hydrous silicic acid of 0 m ² / g. 2. 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 compound is used as a polymerization initiator, and a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound are used. The rubber composition according to claim 1, which is obtained by polymerizing 3. A conjugated diene-based polymer obtained by polymerization using hydrocarbyllithium as an organolithium compound, having a hydrogen atom at one end and a polymerization-active end at the other end. The rubber composition according to claim 2. 4. A conjugated diene-based polymer obtained by polymerization using a lithium amide compound as an organolithium compound, having a nitrogen-containing group at one end and a polymerization-active end at the other end. The rubber composition according to claim 2, which is a certain one. 5. An imino group-containing hydrocarbyloxysilane compound represented by the general formula (I), wherein the imino group bonded to A ¹ is an ethylideneamino group; a 1-methylpropylideneamino group; 1,3-dimethylbutylidene The rubber composition according to any one of claims 1 to 4, which is an amino group; a 1-methylethylideneamino group; a 4-N, N-dimethylaminobenzylideneamino group or a cyclohexylideneamino group. 6. The modified conjugated diene-based polymer of the component (A) has a glass transition point of -90 to -30 ° C. measured by a differential scanning calorimeter (DSC). The rubber composition as described in the above. 7. The modified conjugated diene-based polymer as the component (A) has a Mooney viscosity (ML _{1 +} 4/100 ° C.) of 10 to 10.
The rubber composition according to any one of claims 1 to 5, wherein the weight ratio is 150. 8. The composition according to claim 1, further comprising 1 to 20% by weight of the silane coupling agent (C) based on the component (B).
The rubber composition according to any one of the above. 9. The rubber composition according to claim 1, further comprising (D) 80 parts by weight or less of carbon black per 100 parts by weight of component (A). 10. A pneumatic tire using the rubber composition according to claim 1 as a tread rubber.