JP2002265678A - Silica-compounded rubber composition for tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition proper for uses such as tire treads or sidewalls which maintain good skid resistance and good exothermic characteristics and simultaneously achieve the reduction in the fuel costs of cars and the improvement in the abrasion resistance of tires in higher balance. SOLUTION: This silica-compounded rubber composition which is used for tires and comprises 100 pts.wt. of rubber components (a)+(b) comprising 20 to 80 wt.% of (a) the high cis-high vinyl polybutadiene and 80 to 20 wt.% of (b) the dienic component except the component (a), 15 to 55 pts.wt. of (c) carbon black and 5 to 40 pts.wt. of (d) silica is characterized in that the microstructure of the high cis-high vinyl polybutadiene comprises 65 to 95% of cis-1,4-structures and 4 to 30% of 1,2-structures.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wet skid performance required for performance such as tire safety and economy.
The present invention relates to a rubber composition for a tire containing silica, which has a high balance of heat generation characteristics, abrasion resistance and low fuel consumption.

The present invention can also be used for tire outer members such as treads and sidewalls of tires, and tire inner members such as carcass, beads and belts, and industrial products such as hoses, belts, rubber rolls and rubber crawlers. .

[0003]

2. Description of the Related Art Polybutadiene has a so-called microstructure in which a bonding portion (1,4) formed by polymerization at the 1,4-position.
-Structure) and the bonding moiety (1, 1, 2) formed by polymerization at the 1,2-position.
2-structure) coexists in the molecular chain. The 1,4-structure is
It is further divided into two types, cis structure and trans structure. On the other hand, the 1,2-structure takes a structure having a vinyl group as a side chain.

[0004] It is known that polybutadienes having different microstructures are produced by polymerization catalysts, and are used for various applications depending on their properties. In particular, polybutadiene having a microstructure containing a small amount of trans structure containing a moderately 1,2-structure in the high cis structure (c) and having high molecular linearity (linearity) is
It has excellent properties of wear resistance, heat resistance and rebound resilience.
Tcp / ML _{1 + 4} is used as an index of linearity. Tcp indicates the degree of entanglement of molecules in a concentrated solution. As Tcp / ML _{1 + 4} is larger, the degree of branching is smaller and the linearity is larger.

As disclosed in Japanese Patent Application Laid-Open No. 9-291108 and the like, high cis is achieved by a polymerization catalyst comprising a metallocene type complex of a vanadium metal compound, an ionic compound of a non-coordinating anion and a cation, and / or an aluminoxane. Producing a polybutadiene having a microstructure with a moderate 1,2-structure and a small trans structure and a high molecular linearity (linearity),
It has been found by the applicant. Since this polybutadiene has excellent properties, application to impact-resistant polystyrene resins, tires, and the like has been studied.

JP-A-11-49924 describes the application of a specific high cis-high vinyl polybutadiene composition to tires, which is useful for tread applications and has both high rebound resilience and skid resistance. It is described.

Car tires are required to have excellent wet skid properties as braking properties and excellent rolling resistance (tan δ) and wear resistance as fuel saving properties, but these properties are inconsistent. It is known that this is the relationship. In recent years, proposals have been made to highly balance the above properties by blending silica having excellent wet skid properties, but this is not sufficient.

[0008]

It is known that the silica compound is excellent in wet skid property and fuel economy, but is deteriorated in abrasion resistance and workability, and the abrasion resistance is high cis BR.
Although improved by use, wet skid resistance may be reduced, and improvement has been desired.

[0009]

According to the present invention, there is provided a high cis-high vinyl polybutadiene (a) comprising 20 to 80% by weight;
100% by weight of a rubber component (a) + (b) comprising 80 to 20% by weight of a diene rubber (b) other than (a), 15 to 55 parts by weight of carbon black (c), and silica (d)
5 to 40 parts by weight of a silica-containing rubber composition for a tire, wherein the high cis-high vinyl polybutadiene (a) has a microstructure having a cis-1,4 structure of 65 to 95%.
And a silica-containing rubber composition for a tire, wherein the 1, 2 structure is 4 to 30%.

In the present invention, the high cis-high vinyl polybutadiene (a) has a formula (I) wherein the relationship between the 5% toluene solution viscosity (T-cp) at 25 ° C. and the Mooney viscosity (ML _{1 + 4} ) is as follows: The silica-containing rubber composition for a tire as described above, which satisfies the following. 1 ≦ T-cp / ML _{1 + 4} ≦ 6. . . (I)

Further, the present invention provides a method for producing a high cis-high vinyl polybutadiene (a) comprising: (A) a metallocene complex of a transition metal compound; (B) an ionic compound of a non-coordinating anion and a cation; Alternatively, the present invention relates to the above silica-containing rubber composition for a tire, which is produced using a catalyst obtained from alumoxane.

[0012] The present invention also relates to the above silica-containing rubber composition for a tire, wherein the diene rubber (b) other than (a) is natural rubber and / or polyisoprene.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As (a) the high cis-high vinyl polybutadiene of the present invention, the microstructure is 65 to 95%, preferably 70 to 90%,
The 2 structure is 4 to 30%, preferably 5 to 25%, more preferably 7 to 15%, and the cis-1,4-structure content is 65 to 95%, preferably 70 to 90%. Also,
The trans-1,4-structure content is preferably 5% or less,
0.5 to 4.0% is particularly preferred.

If the microstructure is outside the above range, wet skid properties and abrasion resistance cannot be well balanced.

That is, when the cis structure is 95% or more, the wet skid property decreases, and when the cis structure is 65% or less, the wear resistance deteriorates, which is not preferable.

Also, (a) the viscosity of a 5% toluene solution of high cis-high vinyl polybutadiene at 25 ° C. (Tc
The relational expression between p) and Mooney viscosity (ML _{1 + 4} ) is in a range satisfying the following expression (I). 1 ≦ T-cp /
ML _{1 + 4} ≦ 6. . . (I) Preferably, 2 ≦ T−cp / ML _{1 + 4} ≦ 6 is satisfied.

The viscosity of the polybutadiene in a toluene solution (Tcp) is preferably 20 to 500, and 30 to 30.
0 is particularly preferred.

The polybutadiene of the present invention preferably has a Mooney viscosity (ML _{1 + 4} ) of from 10 to 200, preferably from 25 to 10
0 is particularly preferred.

The molecular weight of the polybutadiene is 0.1 to 10 as an intrinsic viscosity [η] measured at 30 ° C. in toluene.
Is preferred, and 0.1 to 3 is particularly preferred.

The molecular weight of the polybutadiene is preferably in the following range as the molecular weight in terms of polystyrene. Number average molecular weight (Mn): 0.2 × 10 ⁵ to 10 × 10 ⁵ ;
More preferably, 0.5 × 10 ^{5 to} 5 × 10 ⁵ weight average molecular weight (Mw): 0.5 × 10 ^{5 to} 20 × 1
0 ⁵ , more preferably 1 × 10 ⁵ to 10 × 10 ⁵

The polybutadiene of the present invention has a molecular weight distribution (Mw / Mn) of preferably 1.5 to 3.5, more preferably 1.6 to 3.

The polybutadiene of the present invention is, for example,
(A) a metallocene complex of a transition metal compound, and (B)
An ionic compound of a non-coordinating anion and a cation and / or
Alternatively, it can be produced by polymerizing butadiene using a catalyst obtained from aluminoxane.

Alternatively, (A) a metallocene complex of a transition metal compound, (B) an ionic compound of a non-coordinating anion and a cation, (C) an organometallic compound of an element of Groups 1 to 3 of the periodic table, and , (D) butadiene using a catalyst obtained from water.

Examples of the metallocene complex of the transition metal compound (A) include metallocene complexes of transition metal compounds of Groups 4 to 8 of the periodic table.

For example, a metallocene complex of a transition metal of Group 4 of the periodic table such as titanium or zirconium (for example, Cp
A metallocene complex of a transition metal of Group V of the periodic table, such as TiCl ₃ ), vanadium, niobium, or tantalum; a metallocene complex of a group 6 transition metal, such as chromium; Complexes.

Among them, a metallocene complex of a transition metal of Group 5 of the periodic table is preferably used.

Examples of the metallocene complex of the transition metal compound of Group V of the periodic table include the following: (1) RM · La, that is, an oxidized number + 1 having a ligand of a cycloalkadienyl group. Group II transition metal compound (2) R _n MX _2-n · La, that is, at least 1
Oxidation number having a ligand of two cycloalkadienyl groups +
2 of the periodic table group 5 transition metal compound _{(3) R n MX 3-} n · La (4) RMX 3 · La (5) RM (O) X 2 · La (6) R n MX 3-n ( NR ') and the like.
Is 1 or 2, a is 0, 1 or 2.)

Among them, RM · La, R _n MX _2-n · L
a, R ₂ M ・ La, RMX ₃・ La, RM (O) X ₂・
La and the like are preferred.

M is preferably a transition metal compound of Group 5 of the periodic table. Specifically, vanadium (V), niobium (N
b) or tantalum (Ta), the preferred metal being vanadium.

R represents a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group,
It represents a fluorenyl group or a substituted fluorenyl group.

As the substituent in the substituted cyclopentadienyl group, the substituted indenyl group or the substituted fluorenyl group, methyl, ethyl, propyl, iso-propyl, n
Linear or branched aliphatic hydrocarbon groups such as -butyl, iso-butyl, sec-butyl, t-butyl and hexyl; aromatic hydrocarbon groups such as phenyl, tolyl, naphthyl and benzyl; and trimethylsilyl And other hydrocarbon groups containing a silicon atom. Further, those in which a cyclopentadienyl ring is bonded to a part of X by a crosslinking group such as dimethylsilyl, dimethylmethylene, methylphenylmethylene, diphenylmethylene, ethylene, and substituted ethylene are also included.

Specific examples of the substituted cyclopentadienyl group include a methylcyclopentadienyl group.

X represents hydrogen, halogen, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, or an amino group. X may be the same or different.

Specific examples of the halogen include a fluorine atom,
Examples include a chlorine atom, a bromine atom and an iodine atom.

Among the above, X represents hydrogen, fluorine atom, chlorine atom, bromine atom, methyl, ethyl, butyl,
Preferred are methoxy, ethoxy, dimethylamino, diethylamino and the like.

L is a Lewis base, which is a general Lewis basic inorganic or organic compound capable of coordinating to a metal. Among them, compounds having no active hydrogen are particularly preferred. Specific examples include ethers, esters, ketones, amines, phosphines, silyloxy compounds, olefins, dienes,
Aromatic compounds, alkynes and the like can be mentioned.

NR 'is an imide group, and R' is a hydrocarbon substituent having 1 to 25 carbon atoms.

As the (A) metallocene complex of a transition metal compound of Group V of the periodic table, a vanadium compound in which M is vanadium is particularly preferable. For example, RV ・ La,
RVX ・ La, R ₂ M ・ La, RMX ₂・ La, RM
X ₃ .La and RM (O) X ₂ .La are preferred. Particularly, RV · La and RMX ₃ · La are preferred.

Specific examples of the compound represented by RMX ₃ .La include cyclopentadienyl vanadium trichloride including the following. Mono-substituted cyclopentadienyl vanadium trichloride, for example, methylcyclopentadienyl vanadium trichloride, ethylcyclopentadienyl vanadium trichloride, propylcyclopentadienyl vanadium trichloride, isopropylcyclopentadienyl vanadium trichloride, t- Butylcyclopentadienyl vanadium trichloride;

1,2-disubstituted cyclopentadienyl vanadium trichloride, for example, (1,2-dimethylcyclopentadienyl) vanadium trichloride and the like can be mentioned.

Penta-substituted cyclopentadienyl vanadium trichloride, for example (pentamethylcyclopentadienyl) vanadium trichloride, (1,2,2
3,4-tetramethyl-5-phenylcyclopentadienyl) vanadium trichloride, (1-methyl-2,
3,4,5-tetraphenylcyclopentadienyl) vanadium trichloride.

Indenyl vanadium trichloride is mentioned. Substituted indenyl vanadium trichloride,
For example, (2-methylindenyl) vanadium trichloride, (2-trimethylsilylindenyl) vanadium trichloride and the like can be mentioned.

Cyclopentadienyl vanadium tri-t-
Butoxide, cyclopentadienyl vanadium i-propoxide, cyclopentadienyl vanadium dimethoxy chloride and the like.

(T-butylamido) dimethyl (η ⁵ -cyclopentadienyl) silanevanadium dichloride,
(T-butylamido) dimethyl (trimethyl- eta ⁵ - cyclopentadienyl) silane vanadium dichloride and the like.

Specific examples of the compound represented by RM (O) X ₂ include cyclopentadienyloxovanadium dichloride, methylcyclopentadienyloxovanadium dichloride, benzylcyclopentadienyloxovanadium dichloride, (1,3 -Dimethylcyclopentadienyl) oxovanadium dichloride, (1-
Butyl-3-methylcyclopentadienyl) oxovanadium dichloride, (pentamethylcyclopentadienyl) oxovanadium dichloride, (trimethylsilylcyclopentadienyl) oxovanadium dichloride, and the like. A methyl compound in which a chlorine atom of each of the above compounds is substituted with a methyl group is also included.

The compounds in which R and X are linked by a hydrocarbon group or a silyl group are also included. For example, (t-butylamido) dimethyl - amides such as (eta ⁵ cyclopentadienyl) silane oxovanadium chloride chloride thereof,
Alternatively, a methyl compound in which a chlorine atom of these compounds is substituted with a methyl group may be used.

Examples thereof include cyclopentadienyloxovanadium dimethoxide, cyclopentadienyloxovanadium dii-propoxide, and cyclopentadienyloxovanadium dit-butoxide. A methyl compound in which a chlorine atom of each of the above compounds is substituted with a methyl group is also included.

(Cyclopentadienyl) bis (diethylamido) oxovanadium and the like.

Among the component (B), the non-coordinating anion constituting the ionic compound of a non-coordinating anion and a cation includes, for example, tetra (phenyl) borate and tetra (fluorophenyl) borate. , Tetrakis (difluorophenyl) borate, tetrakis (trifluorophenyl) borate, tetrakis (tetrafluorophenyl) borate, tetrakis (pentafluorophenyl)
Borate, tetrakis (3,5-bistrifluoromethylphenyl) borate, tetrakis (tetrafluoromethylphenyl) borate, tetra (triyl) borate
, Tetra (xylyl) borate, triphenyl (pentafluorophenyl) borate, tris (pentafluorophenyl) (phenyl) borate, tridecahydride-7,8-dicarboundecaborate, tetra Fluoroborate, hexafluorophosphate and the like can be mentioned.

On the other hand, examples of the cation include a carbonium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptyltrienyl cation, and a ferrocenium cation having a transition metal.

Specific examples of the carbonium cation include:
Examples include trisubstituted carbonium cations such as triphenylcarbonium cation and trisubstituted phenylcarbonium cation. Specific examples of the tri-substituted phenylcarbonium cation include tri (methylphenyl)
Examples thereof include a carbonium cation and a tri (dimethylphenyl) carbonium cation.

Specific examples of the ammonium cation include:
Trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tripropylammonium cation, tributylammonium cation, tri (n-butyl) ammonium cation, N, N-dimethylanilinium cation;
N-diethylanilinium cation, N, N-2,4,
N, N- such as 6-pentamethylanilinium cation
Dialkylanilinium cation, di (i-propyl)
Examples thereof include a dialkylammonium cation such as an ammonium cation and a dicyclohexylammonium cation.

Specific examples of the phosphonium cation include:
Triarylphosphonium cations such as triphenylphosphonium cation, tri (methylphenyl) phosphonium cation and tri (dimethylphenyl) phosphonium cation can be mentioned.

As the ionic compound, those arbitrarily selected and combined from the non-coordinating anions and cations exemplified above can be preferably used.

Among the ionic compounds, triphenylcarbonium tetrakis (pentafluorophenyl) borate, triphenylcarbonium tetrakis (fluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) )
And 1,1'-dimethylferrocenium tetrakis (pentafluorophenyl) borate are preferred. The ionic compounds may be used alone or in combination of two or more.

Alumoxane may be used as the component (B). The alumoxane is obtained by bringing an organic aluminum compound into contact with a condensing agent, and includes a chain aluminoxane represented by the general formula (-Al (R ') O-) n or a cyclic aluminoxane. (R ′ is a hydrocarbon group having 1 to 10 carbon atoms,
Also includes those partially substituted with halogen atoms and / or alkoxy groups. n is the degree of polymerization, and is 5 or more, preferably 1
0 or more). Examples of R ′ include a methyl, ethyl, propyl, and isobutyl group, and a methyl group is preferable. Examples of the organoaluminum compound used as a raw material of the aluminoxane include trialkylaluminums such as trimethylaluminum, triethylaluminum, and triisobutylaluminum, and mixtures thereof.

Alumoxane using a mixture of trimethylaluminum and tributylaluminum as a raw material can be suitably used.

As the condensing agent, a typical one is water. In addition, any condensing agent capable of condensing the trialkylaluminum, for example, adsorbed water such as an inorganic substance, diol, etc. .

The conjugated diene may be polymerized by combining the components (A) and (B) with an organometallic compound of a Group 1 to 3 element of the periodic table as the component (C).
The addition of the component (C) has the effect of increasing the polymerization activity. Examples of the organometallic compounds of Group 1 to 3 elements of the periodic table include organoaluminum compounds, organolithium compounds, organomagnesium compounds, organozinc compounds, and organoboron compounds.

Specific compounds include methyllithium, butyllithium, phenyllithium, benzyllithium, neopentyllithium, trimethylsilylmethyllithium, bistrimethylsilylmethyllithium, dibutylmagnesium, dihexylmagnesium, diethylzinc, dimethylzinc, trimethylaluminum, Examples thereof include triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, boron trifluoride, and triphenylboron.

Further, ethyl magnesium chloride,
Organic metal halides such as butylmagnesium chloride, dimethylaluminum chloride, diethylaluminum chloride, sesquiethylaluminum chloride and ethylaluminum dichloride, and hydrogenated organometallic compounds such as diethylaluminum hydride and sesquiethylaluminum hydride are also included. Further, two or more kinds of organometallic compounds can be used in combination.

As a combination of the above catalyst components, (A)
RMX ₃ such as cyclopentadienyl vanadium trichloride (CpVCl ₃ ) or cyclopentadienyl oxovanadium dichloride (CpV
A combination of RM (O) X ₂ such as (O) Cl ₂ ), triphenylcarbenium tetrakis (pentafluorophenyl) borate as the component (B), and a trialkylaluminum such as triethylaluminum as the component (C) is preferred. Used.

When an ionic compound is used as the component (B), the above alumoxane may be used in combination as the component (C).

Although the mixing ratio of each catalyst component varies depending on various conditions and combinations, the molar ratio of the metallocene complex of component (A) to the aluminoxane of component (B) is preferably
1: 1 to 1: 100000, more preferably 1:10
1: 10000. The molar ratio of the metallocene complex of the component (A) to the ionic compound of the component (B) is preferably from 1: 0.1 to 1:10. The molar ratio of the metallocene complex of the component (A) to the organometallic compound of the component (C) is
Preferably it is 1: 0.1 to 1: 10000. The order of adding the catalyst components is not particularly limited.

In the present invention, the catalyst system
Further, it is preferable to add water as the component (D).
The molar ratio (C) / (D) of the organoaluminum compound of the component (C) to water of the component (D) is preferably from 0.66 to 0.66.
5, more preferably 0.7 to 1.5.

The order of addition of the catalyst component is not particularly limited, but can be, for example, in the following order. The component (D) is added to the conjugated diene compound monomer to be polymerized or a mixture of the monomer and the solvent, the component (C) is added, and then the components (A) and (B) are added in an arbitrary order. After adding the components (D) and (C) to the conjugated diene compound monomer to be polymerized or a mixture of the monomer and the solvent,
The components (A) and (B) are added in any order.

At the time of polymerization, hydrogen can be allowed to coexist if necessary. The amount of hydrogen is preferably not more than 500 mmol per 1 mol of the conjugated diene, or
12 L or less at 20 ° C. and 1 atm, more preferably 50 L
Mmol or less, or 1.2 L or less at 20 ° C. and 1 atm.

Here, the butadiene monomer to be polymerized may be a whole or a part. In the case of some of the monomers, the above contact mixture can be mixed with the remaining monomer or the remaining monomer solution.

In addition to butadiene monomer, isoprene,
Conjugated dienes such as 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2,3-dimethylbutadiene, 2-methylpentadiene, 4-methylpentadiene and 2,4-hexadiene, ethylene, propylene, butene-
Acyclic monoolefins such as 1, butene-2, isobutene, pentene-1, 4-methylpentene-1, hexene-1, octene-1, cyclopentene, cyclohexene,
Contains a small amount of a cyclic monoolefin such as norbornene and / or an aromatic vinyl compound such as styrene or α-methylstyrene, a non-conjugated diolefin such as dicyclopentadiene, 5-ethylidene-2-norbornene, and 1,5-hexadiene. You may go out.

The polymerization method is not particularly limited.
Alternatively, bulk polymerization using 1,3-butadiene itself as a polymerization solvent can be applied. Toluene, benzene,
Aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as n-hexane, butane, heptane and pentane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; olefinic hydrocarbons such as 1-butene and 2-butene , Mineral spirits, solvent naphtha, kerosene and the like; and halogenated hydrocarbon solvents such as methylene chloride and the like.

In the present invention, it is preferable that the above-mentioned catalyst is preliminarily polymerized at a predetermined temperature. The prepolymerization can be performed by a gas phase method, a slurry method, a bulk method, or the like. The solid obtained in the prepolymerization can be used after the separation in the main polymerization, or the main polymerization can be carried out without separation.

The polymerization temperature is preferably in the range of -100 to 200 ° C, particularly preferably in the range of -50 to 120 ° C. The polymerization time is preferably in the range of 2 minutes to 12 hours, particularly preferably in the range of 5 minutes to 6 hours.

Diene rubber (b) other than (a) of the present invention
Examples include high-cis polybutadiene rubber, low-cis polybutadiene rubber (BR), emulsion-polymerized or solution-polymerized styrene-butadiene rubber (SBR), natural rubber, polyisoprene rubber, and ethylene propylene diene rubber (EPD).
M), nitrile rubber (NBR), butyl rubber (II
R), chloroprene rubber (CR) and the like.

Derivatives of these rubbers, for example, polybutadiene rubber modified with a tin compound and the above-mentioned rubber modified with epoxy, silane or maleic acid can also be used. These rubbers can be used alone or in combination of two or more. They may be used in combination.

The carbon black of the component (c) of the present invention is a carbon black having a particle size of 90 nm or less and a dibutyl phthalate (DBP) oil absorption of 70 ml / 100 g or more. For example, FEF, FF, GPF, SAF,
ISAF, SRF, HAF and the like. Examples of the silica as the component (d) include silicic anhydride by a dry method and hydrous silicic acid and synthetic silicate by a wet method.

Further, as a rubber reinforcing agent, an inorganic reinforcing agent such as activated calcium carbonate or ultrafine magnesium silicate, a syndiotactic 1.2 polybutadiene resin, a polyethylene resin, a polypropylene resin, a high styrene resin, a phenol resin, a lignin, a modified Organic reinforcing agents such as melamine resin, coumarone indene resin and petroleum resin may be mixed.

The mixing ratio of the rubber composition of the present invention is 20 to 80% by weight of high cis-high vinyl polybutadiene (a),
100% by weight of a rubber component (a) + (b) comprising 80 to 20% by weight of a diene rubber (b) other than (a), 15 to 55 parts by weight of carbon black (c), and silica (d)
5 to 40 parts by weight.

Preferably, a rubber component (a) comprising 30 to 70% by weight of a high cis-high vinyl polybutadiene (a) and 70 to 30% by weight of a diene rubber (b) other than (a)
+ (B) 100 parts by weight and carbon black (c) + silica (d) are 30 to 80 parts by weight. If the amount of carbon black (c) + silica (d) is at most 20 parts by weight, the abrasion resistance will decrease.

The silica-containing rubber composition for a tire of the present invention can be obtained by kneading the above-mentioned components using a conventional Banbury, open roll, kneader, twin-screw kneader or the like.

In the rubber composition of the present invention, if necessary,
Compounding agents usually used in the rubber industry, such as a vulcanizing agent, a vulcanizing aid, an antioxidant, a filler, a process oil, zinc white, and stearic acid, may be kneaded.

As the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxides, resin vulcanizing agents, and metal oxides such as magnesium oxide are used.

As the vulcanization aid, known vulcanization aids such as aldehydes, ammonias, amines, guanidines, thioureas, thiazoles, thiurams, dithiocarbamates, xanthates and the like can be used.

Examples of the filler include inorganic fillers such as calcium carbonate, basic magnesium carbonate, clay, Lissajous, and diatomaceous earth, and organic fillers such as recycled rubber and powdered rubber.

As the anti-aging agent, amine / ketone type,
Examples include imidazole-based, amine-based, phenol-based, sulfur-based, and phosphorus-based.

As the process oil, any of aromatic, naphthenic and paraffinic oils may be used.

The rubber composition of the present invention has a skid resistance
Improved fuel efficiency and abrasion resistance while maintaining heat generation characteristics, resulting in a more highly balanced tread and tire.
It is suitable for applications such as sidewalls.

[0087]

EXAMPLES Microstructure was performed by infrared absorption spectroscopy. Cis 740 cm ^-1 , transformer 967c
The microstructure was calculated from the absorption intensity ratio between m ^-1 and 910 cm ^-1 of vinyl.

[Η] was measured at a temperature of 30 ° C. in a toluene solution. Mooney viscosity (ML _{1 + 4} ) is JIS K6300
It measured according to. The viscosity of the toluene solution (Tcp) is
After dissolving 2.28 g of the polymer in 50 ml of toluene, a standard solution for viscometer calibration (JIS Z8809) was used as a standard solution. Using 400
It was measured at 25 ° C.

The properties of the vulcanized rubber composition were evaluated as follows. Skid resistance index: A ground glass surface was wetted with water using a British portable skid tester in accordance with ASTM E303 and measured at room temperature. The higher the index, the better the skid resistance.

Abrasion resistance index: Measured at a slip rate of 20% using a Lambourn abrasion tester in accordance with JIS K6264, and evaluated using an index with Comparative Example 1 being 100. The larger the index, the better the wear resistance.

Exothermic characteristic index: A test was conducted at a test temperature of 100 ° C. for 25 minutes in accordance with JIS K6265, and the difference between the test temperature and the start temperature was measured. The larger the index, the smaller and better the calorific value.

Tan δ index: Measured at a temperature of 60 ° C., a frequency of 10 Hz, and a dynamic strain of 2% using a viscoelasticity measuring device manufactured by Rheometrics Co., Ltd. The larger the index, the smaller and better the tan δ.

(Reference Example 1) (Production of high cis-high vinyl polybutadiene) 30 wt.
% Toluene solution containing 1.3% butadiene (1.
3.5 L of 3-butadiene: 814 g) is charged and stirred. Next, hydrogen gas was introduced to 0.092 kgG / c.
It was high m ² pressure only. 2.25 mmol of triethylaluminum over 30 minutes at 30 ° C. and then 0.039 mmol of trityltetra (perfluorophenyl) borate
l, 0.026 mmol of cyclopentadienyl vanadium trichloride was continuously added, and the polymerization temperature was 40 ° C.
For 30 minutes. After the polymerization, the reaction was terminated by injecting an equivalent mixture of ethanol and heptane containing 2,6-di-t-butyl-p-cresol, and the solvent was evaporated and dried. The yield of the obtained polymer was 32%, and the microstructure, Mooney viscosity, 5% toluene solution viscosity, and t-cp / ML ratio were as shown in Table 1. It was shown to.

[0094]

[Table 1]

(Examples 1 to 6) (Comparative Examples 1 to 5) The high cis-high vinyl polybutadiene (HCH
Using V), a natural rubber and carbon black were kneaded with a 1.7 L test Banbury mixer according to the compounding recipe shown in Table 2, and then the vulcanizing agent was mixed with an open roll. Next, press vulcanization was performed at a temperature of 150 ° C. for 30 minutes.
Abrasion resistance, heat generation characteristics and tan δ were evaluated. The results are shown in Tables 2 and 3. The compositions of the examples have improved abrasion resistance and tan δ, which is an index of fuel economy, while maintaining wet skid resistance and heat generation characteristics.

In the composition of the comparative example, the wet skid resistance was reduced when a commercially available BR was used or when no silica was used, and the abrasion resistance was reduced when SBR was used or when the amount of carbon black was small.

[0097]

[Table 2]

[0098]

[Table 3]

[0099]

EFFECT OF THE INVENTION The silica-containing rubber composition for a tire according to the present invention has improved fuel economy and abrasion resistance while maintaining skid resistance and exothermic characteristics, and has a more highly balanced tire. It is suitable for applications such as treads and sidewalls.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/04 C08K 3/04 3/36 3/36 C08L 7/00 C08L 7/00 F term (reference) 4J002 AC01X AC03W AC03X AC06X AC07X AC08X AC09X BB15X BB18X BL00W DA036 DJ017 FD010 FD030 FD140 FD150 GN01 4J028 AA01A AB00A AB01A AC02A AC10A AC22A AC31A AC32A AC39A AC42A AC47A ACBB01BA02A00B00A 00B BC AB01 AC02 AC10 AC22 AC31 AC32 AC39 AC42 AC47 AC48 AD00 BA00A BA01B BB00B BB01B BC12B BC25B DA06 EB13 FA01 FA02

Claims (4)

[Claims] 1. High cis-high vinyl polybutadiene (a)
A rubber component (a) + comprising 20 to 80% by weight and 80 to 20% by weight of a diene rubber other than (a) (b)
(B) 100 parts by weight and carbon black (c) 15
A silica-containing rubber composition for a tire, the rubber composition comprising -55 parts by weight and 5-40 parts by weight of silica (d).
The microstructure of high vinyl polybutadiene (a) is cis-
1,4 structure is 65-95% and 1,2 structure is 4-30%
A silica-containing rubber composition for a tire, comprising: 2. The high cis-high vinyl polybutadiene (a).
Is the 5% toluene solution viscosity at 25 ° C (T-cp)
Mooney viscosity (ML 1 + ₄₎ Tires for silica-containing rubber composition according to claim 1 which relation is characterized by satisfying the following formula (I) of the. 1 ≦ T-cp / ML _{1 + 4} ≦ 6. . . (I) 3. The high cis-high vinyl polybutadiene (a) is (A) a metallocene complex of a transition metal compound,
And (B) a silica-containing rubber composition for a tire according to claim 1 or 2, which is produced using a catalyst obtained from an ionic compound of a non-coordinating anion and a cation and / or an alumoxane. object. 4. The silica-containing rubber composition for a tire according to claim 1, wherein the diene rubber (b) other than (a) is natural rubber and / or polyisoprene.