JP2000038473A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition exhibiting high fatigue resistance, ozone resistance, etc., without impairing its damping characteristics by blending a specific ethylene-based copolymer rubber with natural rubber and polybutadiene rubber. SOLUTION: This rubber composition is obtained by compounding (A) 10-60 pts.wt. of an ethylene-based copolymer rubber with an iodine value of 5-45, Mooney viscosity of 15-350, the ratio of weight-average molecular weight in terms of polystyrene (Mw) to number-average molecular weight in terms of polystyrene (Mn) of 2.5-15, glass transition temperature of -50 to -80 deg.C, and degree of branching index B of 0.60-0.95, produced by copolymerization among (i) ethylene, (ii) a 3-12C α-olefin, and (iii) a monomer component predominant in a 7-30C non-conjugated polyene of the formula (X is a 1-20C hydrocarbon; R1 and R2 are each H or a 1-8C alkyl, but being not H at the same time; R3 is a 1-8C alkyl) in the molar ratio (i)/(ii) of (40:60) to (90:10), with (B) 10-80 pts.wt. of natural rubber and (C) 10-70 pts.wt. of polybutadiene rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rubber composition, and more particularly, to processing characteristics, weather resistance, ozone resistance, and fatigue resistance without substantially impairing the damping property of a conjugated diene rubber. The present invention relates to a rubber composition having excellent properties and the like, and particularly useful as a tire sidewall.

[0002]

2. Description of the Related Art As rubber materials for tires, conjugated diene rubbers such as natural rubber, polybutadiene rubber and styrene-butadiene rubber are usually used from the viewpoint of abrasion resistance and durability. However, these conjugated diene rubbers have poor weather resistance, and their improvement is required. In order to improve this point, blending of an ethylene / propylene / non-conjugated diene copolymer rubber (hereinafter, also referred to as “EPDM”) having excellent weather resistance has been studied a lot, but EPDM is conjugated. Compared to diene rubber
Because the vulcanization rate is inferior, when both rubbers are blended,
It is inferior in co-vulcanizability and, as a result, although the weather resistance is slightly improved, there is a problem that the mechanical strength and durability are very poor.

On the other hand, in recent years, there have been many proposals concerning the production of an ethylene / α-olefin / non-conjugated diene copolymer rubber using a metallocene catalyst, and it has been difficult to carry out polymerization with a conventional Ziegler-Natta catalyst. It is reported that the monomers copolymerize. For example, Japanese Patent Laid-Open No. 2-5
In JP-A-1512 and JP-A-6-128427, by using a linear non-conjugated diene represented by 7-methyl-1,6-octadiene, vulcanization can be carried out more than in the case of 5-ethylidene-2-norbornene. A method has been proposed in which the speed is high and the co-vulcanizability of an ethylene / α-olefin / non-conjugated diene-based copolymer rubber and a conjugated diene-based rubber is improved. However, originally, ethylene / α-olefin /
Non-conjugated diene-based copolymer rubber and conjugated diene-based rubber have poor compatibility, and ethylene / α-olefin / non-conjugated diene-based copolymer rubber obtained by metallocene catalyst has a narrow molecular weight distribution. It has the drawback of poor processability, and it has problems that it does not mix well with the conjugated diene rubber during kneading of Banbury or the like and that it survives. Thus, conventional ethylene / α-olefin /
A rubber composition containing a non-conjugated diene copolymer rubber cannot be sufficiently satisfied in terms of processing characteristics.

On the other hand, as a method for improving the processing characteristics of a metallocene-based catalyst-based polymer, a component having a different composition or a different molecular weight from an ethylene / α-olefin / non-conjugated diene-based copolymer rubber, which has been used for a conventional vanadium-based catalyst. It is also conceivable a method of blending, for example, a multi-stage polymerization method in which several reactors for producing a copolymer are connected in series and polymerization is continuously performed, or two or more types having different reactivities in the reactor. A method of charging the catalyst may, for example, be mentioned.
However, these methods have problems such as poor productivity, cost increase, and difficulty in controlling polymerization, and are not industrially advantageous.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is directed to a specific ethylene copolymer rubber having excellent covulcanizability and processability with a conjugated diene rubber. Is blended with an appropriate range of natural rubber and polybutadiene rubber to provide an excellent balance of fatigue resistance and ozone resistance without impairing the damping characteristics inherent in conjugated diene rubbers such as natural rubber and polybutadiene rubber. In particular, it is an object of the present invention to provide a rubber composition useful for tire sidewall applications.

[0006]

The present invention relates to (A) ethylene, an α-olefin having 3 to 12 carbon atoms and a linear or branched chain having 7 to 30 carbon atoms represented by the following structural formula (I). Non-conjugated polyene (hereinafter referred to as “(I) non-conjugated polyene”
(B) 10 to 60 parts by weight of an ethylene copolymer rubber, which is obtained by polymerizing a monomer component containing (B) natural rubber 10 and satisfies the following requirements (1) to (6). ~
80 parts by weight, and (C) polybutadiene rubber 10 to 7
The present invention provides a rubber composition containing 0 parts by weight (provided that (A) + (B) + (C) = 100 parts by weight). Structural formula (I); (Wherein X is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ is an alkyl group having 1 to 8 carbon atoms. (Except when both R ¹ and R ² are hydrogen atoms.) (1) The molar ratio of ethylene to α-olefin having 3 to 12 carbon atoms (ethylene / α-olefin) is 40/60 to 9
(2) iodine value is in the range of 5-45, (3) Mooney viscosity (ML _{1 + 4} , 100 ° C.)
(4) The ratio (Mw / Mn) of the polystyrene-equivalent weight average molecular weight (Mw) to the polystyrene-equivalent number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 2 .5
(5) the glass transition temperature (Tg) determined by a differential scanning calorimeter (DSC) is −50 to −80 ° C.
And (6) the degree of branching index B is 0.60 to 0.9.
5 range. Here, the monomer components constituting the ethylene copolymer rubber (A) further include α, ω-diene represented by the following structural formula (II) (hereinafter referred to as “(II) α, ω
-Diene "). Structural formula _{(II); CH 2 = CH-} (CH 2) m -CH = CH 2 ( wherein, m is an integer of from 1 to 10.)

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene copolymer rubber (A) used in the rubber composition of the present invention is ethylene, having 3 carbon atoms.
To 12 and the non-conjugated polyene represented by the structural formula (I), preferably further added to the structural formula (I
It is a copolymer obtained by polymerizing a monomer component containing α, ω-diene as a main component represented by I). Here, as the α-olefin, for example, propylene, 1-butene,
1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 5-methyl-1-hexene, 1-octene, 5-ethyl-1-
Hexene, 1-nonene, 1-decene, 1-dodecene, and the like, preferably propylene, 1-butene,
-Hexene, 1-octene is used. These α-
The olefins can be used alone or as a mixture of two or more.

(A) The molar ratio of ethylene to α-olefin (ethylene / α-olefin) in the ethylene copolymer rubber is from 40/60 to 90/10, preferably 6
0/40 to 87/13 [Requirement (1) above]. In this case, if the above molar ratio is less than 40/60, the mechanical strength is not sufficiently exhibited, while 90/10
If it exceeds, processing characteristics are inferior.

The non-conjugated polyene represented by the structural formula (I) includes, specifically, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 5-methyl-1 , 5-heptadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,6-octadiene, 7-
Methyl-1,6-octadiene, 5,7-dimethyl-
1,6-octadiene, 7-methyl-1,7-nonadiene, 8-methyl-1,7-nonadiene, 8-methyl-
1,8-decadiene, 9-methyl-1,8-decadiene, 9-methyl-1,9-undecadiene, 10-methyl-1,9-undecadiene, 10-methyl-1,10
-Dodecadiene, 11-methyl-1,10-dodecadiene, 12-methyl-1,11-tridecadiene, 13-
Methyl-1,11-tridecadiene, 12-methyl-
1,12-tetradecadiene, 13-methyl-1,12
-Tetradecadiene, 13-methyl-1,13-pentadecadiene, 14-methyl-1,13-pentadecadiene, 4-ethylidene-1,6-octadiene, 7-methyl-4-ethylidene-1,6 -Octadiene, 7-methyl-4-ethylidene-1,6-nonadiene, 7-ethyl-4-ethylidene-1,6-nonadiene, 6,7-dimethyl-4-ethylidene-1,6-octadiene, 6,7
-Dimethyl-4-ethylidene-1,6-nonadiene, 4
-Ethylidene-1,6-decadiene, 7-methyl-4-
Ethylidene-1,6-decadiene, 7-methyl-6-propyl-4-ethylidene-1,6-octadiene, 4-
Ethylidene-1,7-nonadiene, 8-methyl-4-ethylidene-1,7-nonadiene, 4-ethylidene-1,
7-undecadiene, 8-methyl-4-ethylidene-
1,7-undecadiene, 7,8-dimethyl-4-ethylidene-1,7-nonadiene, 7,8-dimethyl-4-
Ethylidene-1,7-decadiene, 7,8-dimethyl-
4-ethylidene-1,7-undecadiene, 8-methyl-7-ethyl-4-ethylidene-1,7-undecadiene, 7,8-diethyl-4-ethylidene-1,7-decadiene, 9-methyl-4- Ethylidene-1,8-decadiene, 8,9-dimethyl-4-ethylidene-1,8-decadiene, 10-methyl-4-ethylidene-1,9-undecadiene, 9,10-dimethyl-4-ethylidene-
1,9-undecadiene, 11-methyl-4-ethylidene-1,10-dodecadiene, 10,11-dimethyl-
4-ethylidene-1,10-dodecadiene, 6,10-
Examples thereof include dimethyl-1,5,9-undecatriene and 5,9-dimethyl-1,4,8-decatriene, and preferably 4-methyl-1,4-hexadiene and 5-methyl-1,4- Hexadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 5,7-dimethyl-1,
6-octadiene, 8-methyl-1,7-nonadiene,
9-methyl-1,8-decadiene, particularly preferably 7
These (I) non-conjugated polyenes in which -methyl-1,6-octadiene is used can be used alone or as a mixture of two or more.

The α, ω-diene represented by the structural formula (II) specifically includes 1,5-hexadiene,
1,6-heptadiene, 1,7-octadiene, 1,8
-Nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene, 1,13-tetradecadiene and the like, and preferably 1,5-hexadiene, 1,7 Octadiene, 1,9-decadiene are used. These (II) α, ω-dienes may be used alone or
Alternatively, two or more kinds can be used in combination. In the present invention, the content of (II) α, ω-diene in the monomer component is usually 0.001 to 3 mol%, preferably 0.1 to 3 mol%.
The range is from 0.01 to 0.3 mol%.

(A) The iodine value of the ethylene copolymer rubber is in the range of 5-45, preferably 10-35 (the above requirement (2)). In this case, if the iodine value is less than 5, the mechanical strength is poor, while if it exceeds 45, the rubber elasticity is impaired.

(A) The ethylene-based copolymer rubber has a Mooney viscosity (ML _{1 + 4} , 100 ° C.) (hereinafter also referred to as “Mooney viscosity”) in the range of 15 to 350, preferably 20 to 300. Requirement (3)]. If it is less than 15, the mechanical strength is inferior, while if it exceeds 350, the processing characteristics are inferior.

(A) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the ethylene copolymer rubber measured by gel permeation chromatography (GPC) is 2 5-1
5, preferably in the range of 3 to 10 (the above requirement (4)).

(A) The glass transition temperature Tg of the ethylene copolymer rubber determined by a differential scanning calorimeter (DSC) is as follows:
It is in the range of −50 to −80 ° C., preferably −55 to −75 ° C. (the above requirement (5)).

(A) The degree of branching index B of the ethylene copolymer rubber is 0.60 to 0.95, preferably 0.70 to 0.95.
0.92 [Requirement (6) above]. The value of the branching degree index B is determined by the intrinsic viscosity [η ₀ ] of the model copolymer rubber having no branching and the polystyrene equivalent weight according to the viscosity-GPC method [Murao Kurata, Journal of the Rubber Society of Japan, (45) 1972]. Viscosity equation [η ₀ ] = KM obtained from the average molecular weight (M _wo )
_wo (where K is a constant), [η ₁ ] is calculated from M _w1 obtained by GPC measurement of the target copolymer rubber, and then the actual measurement of the target copolymer [η ₂ ] Divided by [η ₁ ] calculated from the above viscosity equation. here,
[Η ₁ ] and [η ₂ ] are in o-dichlorobenzene,
M _wi is a value determined at 135 ° C. in o-dichlorobenzene by a GPC measurement method.

The (A) ethylene copolymer rubber used in the present invention can be produced by an appropriate method such as a gas phase polymerization method, a solution polymerization method, and a slurry polymerization method. These polymerization operations can be carried out in a batch system or a continuous system. In the above solution polymerization method or slurry polymerization method, an inert hydrocarbon is usually used as a reaction medium. Such inert hydrocarbon solvents include, for example, n-pentane, n-hexane, n-heptane, n-
Aliphatic hydrocarbons such as octane, n-decane and n-dodecane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and aromatic hydrocarbons such as benzene, toluene and xylene. These hydrocarbon solvents can be used alone or as a mixture of two or more. Further, the raw material monomer can be used as a hydrocarbon solvent.

As the polymerization catalyst used for producing the ethylene copolymer rubber (A), for example, V, T
An olefin polymerization catalyst comprising a compound of a transition metal selected from i, Zr and Hf and an organometallic compound can be exemplified. The transition metal compound and the organometallic compound can be used alone or in combination of two or more. As a particularly preferred example of such an olefin polymerization catalyst, a metallocene catalyst comprising a metallocene compound and an organoaluminum compound or an ionic compound which reacts with the metallocene compound to form an ionic complex can be mentioned. Hereinafter, the polymerization catalyst for producing the ethylene copolymer rubber (A) will be described more specifically, but a polymerization catalyst other than the following may be used in some cases.

Examples of the above metallocene catalyst include, for example,
A catalyst composed of the following components (D) and (E) or a catalyst composed of the following components (F) and (G) is exemplified. Component (D) is a transition metal compound represented by the following general formula (1). In the formula, M is a metal of Group 4 of the periodic table, (C ₅ R _m ) is a cyclopentadienyl group or a substituted cyclopentadienyl group, and each R may be the same or different and includes a hydrogen atom, An alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, an alkaryl group having 7 to 40 carbon atoms or an aralkyl group having 7 to 40 carbon atoms, or two adjacent carbon atoms are bonded. E is an atom having a non-bonded electron pair, R 'is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, and a carbon atom having 7 to 8 carbon atoms. 40 alkaryl groups or 7 to 7 carbon atoms
40 is an aralkyl group, R ″ is an alkylene group having 1 to 20 carbon atoms, dialkyl silicon or dialkyl germanium, and is a group that binds two ligands;
Is 1 or 0; when s is 1, m is 4; n is a number smaller than the valence of E by 2; when s is 0, m is 5,
n is a number less than the valence of E; when n ≧ 2, each R ′ may be the same or different; each R ′ may be bonded to form a ring; and Q is a hydrogen atom A halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, an alkaryl group having 7 to 40 carbon atoms or an aralkyl group having 7 to 40 carbon atoms, and p and q are 0 to 4
And satisfies the relationship 0 <p + q ≦ 4.

Specific examples of component (D) include bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis (cyclopentadienyl) zirconium dimethyl, and bis (cyclopentadienyl). ) Zirconium diphenyl, dimethylsilylbis (cyclopentadienyl) zirconium dichloride, dimethylsilylbis (cyclopentadienyl) zirconium dimethyl, methylenebis (cyclopentadienyl) zirconium dichloride, ethylenebis (cyclopentadienyl) zirconium dichloride, bis (Indenyl) zirconium dichloride, bis (indenyl) zirconium dimethyl, dimethylsilylbis (indenyl) zirconium dichloride, methylenebis (indenyl) zircon Umujikurorido, bis (4,
5,6,7-tetrahydroindenyl) zirconium dichloride, bis (4,5,6,7-tetrahydroindenyl) zirconium dimethyl, dimethylsilylbis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, dimethyl Silyl bis (4,5,6,7
-Tetrahydroindenyl) zirconium dimethyl, ethylenebis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, bis (methylcyclopentadienyl) zirconium dichloride, bis (methylcyclopentadienyl) zirconium dimethyl, dimethylsilyl Bis (3-methyl-1-cyclopentadienyl)
Zirconium dichloride, methylene bis (3-methyl-
1-cyclopentadienyl) zirconium dichloride,
Bis (tert-butylcyclopentadienyl) zirconium dichloride, dimethylsilylbis (3-tert-butyl-1-cyclopentadienyl) zirconium dichloride, bis (1,3-dimethylcyclopentadienyl) zirconium dichloride, Dimethylsilylbis (2,4-
Dimethyl-1-cyclopentadienyl) zirconium dichloride, bis (1,2,4-trimethylcyclopentadienyl) zirconium dichloride, dimethylsilylbis (2,3,5-trimethyl-1-cyclopentadienyl) zirconium dichloride , Bis (fluorenyl) zirconium dichloride, dimethylsilylbis (fluorenyl) zirconium dichloride, (fluorenyl) (cyclopentadienyl) zirconium dichloride, dimethylsilyl (fluorenyl) (cyclopentadienyl) zirconium dichloride, diphenylmethylene (fluorenyl) (cyclo (Pentadienyl) zirconium dichloride, isopropylene (fluorenyl) (cyclopentadienyl) zirconium dichloride, (tertiary butylamide) (1, 2, , 4,5-pentamethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (tertiary butylamide) (2,3,4,5-tetramethyl-1-cyclopentadienyl) zirconium dichloride, methylene (tertiary) Butyramide) (2,3,4,5
-Tetramethyl-1-cyclopentadienyl) zirconium dichloride, (phenoxy) (1,2,3,4,5
-Pentamethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (o-phenoxy) (2,
3,4,5-tetramethyl-1-cyclopentadienyl) zirconium dichloride, methylene (o-phenoxy) (2,3,4,5-tetramethyl-1-cyclopentadienyl) zirconium dichloride, ethylene (o −
Phenoxy) (2,3,4,5-tetramethyl-1-cyclopentadienyl) zirconium dichloride, bis (dimethylamido) zirconium dichloride, bis (diethylamido) zirconium dichloride, bis (dithienyl)
Tert-butylamido) zirconium dichloride, dimethylsilylbis (methylamido) zirconium dichloride, dimethylsilylbis (tertiary-butylamido) zirconium dichloride, and the like, and compounds in which zirconium in these compounds is replaced with titanium or hafnium. However, the present invention is not limited to this. The above transition metal compounds can be used alone or in combination of two or more.

The component (E) is an aluminoxane compound having a unit represented by the following general formula (2), and although the chemical structure is not necessarily clear, a linear, cyclic or cluster compound, Alternatively, it is presumed to be a mixture of these compounds. -[Al (R) -O]-... (2) wherein R is an alkyl group having 1 to 20 carbon atoms, and 6 to 4 carbon atoms.
An aryl group having 0, an alkaryl group having 7 to 40 carbon atoms, or an aralkyl group having 7 to 40 carbon atoms, preferably a methyl group, an ethyl group, an isobutyl group, and particularly preferably a methyl group. The aluminoxane compound can be produced by a known method involving a reaction between water and the organoaluminum compound having at least one R group. The ratio of the components (D) and (E) used is usually from 1/1 to 1 / 100,000, preferably from 1/100, as a molar ratio of transition metal to aluminum atom (transition metal / aluminum atom). It is in the range of 5 to 1 / 50,000.

Next, the component (F) is a transition metal alkyl compound represented by the following general formula (3). In the formula, M is a metal of Group 4 of the periodic table, (C ₅ R _m ) is a cyclopentadienyl group or a substituted cyclopentadienyl group, each R may be the same or different, and represents a hydrogen atom, An alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, an alkaryl group having 7 to 40 carbon atoms or an aralkyl group having 7 to 40 carbon atoms, or two adjacent carbon atoms are bonded. E is an atom having a non-bonded electron pair, R 'is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, and a carbon atom having 7 to 8 carbon atoms. 40 alkaryl groups or 7 to 7 carbon atoms
40 is an aralkyl group, R ″ is an alkylene group having 1 to 20 carbon atoms, dialkyl silicon or dialkyl germanium, and is a group that binds two ligands;
Is 1 or 0; when s is 1, m is 4; n is a number smaller than the valence of E by 2; when s is 0, m is 5,
n is a number less than the valence of E, and when n ≧ 2, each R ′ may be the same or different, and each R ′ may be bonded to form a ring; C1-C20 alkyl group, C6-C40 aryl group, C7-C
An alkaryl group of 40 or an aralkyl group of 7 to 40 carbon atoms, p and q are integers of 0 to 3,
<P + q ≦ 4.

Specific examples of component (F) include bis (cyclopentadienyl) zirconium dimethyl, bis (cyclopentadienyl) zirconium diethyl, bis (cyclopentadienyl) zirconium diisobutyl, and bis (cyclopentadienyl) Zirconium diphenyl, bis (cyclopentadienyl) zirconium di {bis (trimethylsilyl) methyl}, dimethylsilylbis (cyclopentadienyl) zirconium dimethyl, dimethylsilylbis (cyclopentadienyl) zirconium diisobutyl, methylenebis (cyclopentadienyl) ) Zirconium dimethyl, ethylene bis (cyclopentadienyl) zirconium dimethyl, bis (indenyl) zirconium dimethyl, bis (indenyl) zirconium diisobutyl, dimethyl Rubis (indenyl) zirconium dimethyl, methylenebis (indenyl) zirconium dimethyl, ethylenebis (indenyl) zirconium dimethyl, bis (4,5,6,7-tetrahydroindenyl) zirconium dimethyl, dimethylsilylbis (4,5,6,7 -Tetrahydro-1-indenyl) zirconium dimethyl, ethylenebis (4,5,6,7-
Tetrahydro-1-indenyl) zirconium dimethyl, bis (methylcyclopentadienyl) zirconium dimethyl, dimethylsilylbis (3-methyl-1-cyclopentadienyl) zirconium dimethyl, bis (third
Tert-butylcyclopentadienyl) zirconium dimethyl, dimethylsilylbis (3-tert-butyl-1-cyclopentadienyl) zirconium dimethyl, bis (1,
3-dimethylcyclopentadienyl) zirconium dimethyl, bis (1,3-dimethylcyclopentadienyl)
Zirconium diisobutyl, dimethylsilylbis (2,
4-dimethyl-1-cyclopentadienyl) zirconium dimethyl, methylenebis (2,4-dimethyl-1-cyclopentadienyl) zirconium dimethyl, ethylenebis (2,4-dimethyl-1-cyclopentadienyl)
Zirconium dimethyl, bis (1,2,4-trimethylcyclopentadienyl) zirconium dimethyl, dimethylsilylbis (2,3,5-trimethyl-1-cyclopentadienyl) zirconium dimethyl, bis (fluorenyl) zirconium dimethyl, dimethyl Silylbis (fluorenyl) zirconium dimethyl, (fluorenyl)
(Cyclopentadienyl) zirconium dimethyl, dimethylsilyl (fluorenyl) (cyclopentadienyl)
Zirconium dimethyl, diphenylmethylene (fluorenyl) (cyclopentadienyl) zirconium dimethyl, isopropylene (fluorenyl) (cyclopentadienyl) zirconium dimethyl, (tertiary butylamide) (1,2,3,4,5-pentamethyl Cyclopentadienyl) zirconium dimethyl, dimethylsilyl (tertiary butylamide) (2,3,4,5-tetramethyl-
1-cyclopentadienyl) zirconium dimethyl, methylene (tert-butylamide) (2,3,4,5-tetramethyl-1-cyclopentadienyl) zirconium dimethyl, (phenoxy) (1,2,3,4 , 5-pentamethylcyclopentadienyl) zirconium dimethyl,
Dimethylsilyl (o-phenoxy) (2,3,4,5-
Tetramethyl-1-cyclopentadienyl) zirconium dimethyl, methylene (o-phenoxy) (2,3
4,5-tetramethyl-1-cyclopentadienyl) zirconium dimethyl, bis (dimethylamido) zirconium dimethyl, bis (diethylamido) zirconium dimethyl, bis (ditert-butylamido) zirconium dimethyl, dimethylsilylbis (methylamido) zirconium Examples thereof include, but are not limited to, dimethyl, dimethylsilylbis (tertiary-butylamido) zirconium dimethyl, and compounds in which zirconium in these compounds is replaced with titanium or hafnium. The above transition metal alkyl compounds can be used alone or in combination of two or more.

The transition metal alkyl compound may be synthesized and used in advance, or may be a transition metal halide in which R ″ in the above general formula (3) is substituted with a halogen atom, and trimethylaluminum, triethylaluminum, diethylaluminum. It may be formed by bringing an organic metal compound such as monochloride, triisobutylaluminum, methyllithium, and butyllithium into contact in a reaction system.

The component (G) is an ionic compound represented by the following general formula (4). In the formula, [L] ^{k +} is a Bronsted acid or a Lewis acid, M ′ is an element belonging to Groups 13 to 15 of the periodic table, and A ₁ to
_An is a hydrogen atom, a halogen atom, and a carbon number of 1 to 2, respectively.
0 alkyl group, C1-C30 dialkylamino group, C1-C20 alkoxy group, C6-C40 aryl group, C6-C40 aryloxy group, C7-C40 alka A reel group, an aralkyl group having 7 to 40 carbon atoms, a halogen-substituted hydrocarbon group having 1 to 40 carbon atoms, an acyloxy group having 1 to 20 carbon atoms, or an organic metalloid group; Is an integer, p is an integer of 1 or more, and q = (k × p).

Specific examples of component (G) include trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, methyl (di-n-butyl) ammonium tetraphenylborate, tetraphenylborate Dimethylanilinium borate, methylpyridinium tetraphenylborate, methyl tetraphenylborate (2-
Cyanopyridinium), methyl tetraphenylborate (4-cyanopyridinium), trimethylammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (pentafluorophenyl) borate, tri-n-butylammonium tetrakis (pentafluorophenyl) borate, tetrakis Methyl (penta-fluorophenyl) borate (di-n-butyl) ammonium, dimethylanilinium tetrakis (pentafluorophenyl) borate, methylpyridinium tetrakis (pentafluorophenyl) borate, methyl (2-cyanopyridinium) tetrakis (pentafluorophenyl) borate ), Methyl tetrakis (pentafluorophenylphenyl) borate (4-cyanopyridinium),
Dimethylanilinium tetrakis [3,5-di- (trifluoromethyl) phenyl] borate, ferrocenium tetraphenylborate, silver tetraphenylborate, ferrocenium tetrakis (pentafluorophenyl) borate, and the like, but are not limited thereto. is not. The above ionic compounds can be used alone or in combination of two or more.

The above component (F) and component (G) are used in a molar ratio [(F) / (G)] of usually 1 / 0.5 to 0.5.
1/20, preferably in the range of 1 / 0.8 to 1/10. (A) The metallocene catalyst used for producing the ethylene copolymer rubber may be used by supporting at least a part of those components on a suitable carrier.
The type of carrier is not particularly limited, and any of inorganic oxide carriers, other inorganic carriers, and organic carriers can be used. In addition, there is no particular limitation on the loading method, and a known method may be appropriately used.

Next, the Mooney viscosity of the polybutadiene rubber (C) is preferably from 10 to 100, and more preferably from 20 to 80.

In the rubber composition of the present invention, the proportion of (A) the ethylene copolymer rubber, (B) natural rubber and (C) polybutadiene rubber is such that the component (A) is 10 to 60 parts by weight, preferably 20 to 50 parts by weight, component (B) is 10 to
80 parts by weight, preferably 20 to 70 parts by weight, the component (C) is 10 to 70 parts by weight, preferably 10 to 60 parts by weight (provided that (A) + (B) + (C) = 100 parts by weight). is there.

The rubber composition of the present invention comprises the above (A)
A vulcanized rubber can be obtained by blending a vulcanizing agent and / or a crosslinking agent with the component (C) as a main component.
Here, among the vulcanizing agents and crosslinking agents used in the present invention, examples of the vulcanizing agent include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, and insoluble sulfur; and inorganics such as sulfur chloride, selenium, and tellurium. Vulcanizing agents such as sulfur-containing organic compounds such as morpholine disulfide, alkylphenol disulfides, thiuram disulfides, and dithiocarbamates. These vulcanizing agents can be used alone or in combination of two or more. In the present invention, the compounding amount of the vulcanizing agent is usually from 0.1 to 100 parts by weight based on a total of 100 parts by weight of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber. It is 10 parts by weight, preferably 0.5 to 5 parts by weight.

Further, a vulcanization accelerator can be used in combination with the vulcanizing agent. Examples of such a vulcanization accelerator include aldehyde ammonias such as hexamethylenetetramine; guanidines such as diphenylguanidine, di (o-tolyl) guanidine and o-tolyl-piguanide; thiocarbanilide and di (o-tolyl) Thioureas such as thiourea, N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea, dilaurylthiourea; mercaptobenzothiazole, dibenzothiazole disulfide, 2- (4-morpholinothio) benzothiazole, 2- (2,2 4-dinitrophenyl) -mercaptobenzothiazole, (N, N'-
Thiazoles such as diethylthiocarbamoylthio) benzothiazole; N-tert-butyl-2-benzothiazylsulfenamide, N, N'-dicyclohexyl-2
-Benzothiazylsulfenamide, N, N'-diisopropyl-2-benzothiazylsulfenamide, N-
Sulfenamides such as cyclohexyl-2-benzothiazylsulfenamide; thiurams such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetra-n-butylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide Zinc dimethylthiocarbamate, zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, zinc ethylphenyldithiocarbamate, sodium dimethyldithiocarbamate,
Carbamates such as copper dimethyldithiocarbamate, tellurium dimethylthiocarbamate and iron dimethylthiocarbamate; and xanthates such as zinc butylthioxanthogenate. These vulcanization accelerators can be used alone or in combination of two or more. The amount of the vulcanization accelerator is usually 0.1 to 20 parts by weight, based on 100 parts by weight of the total of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber. Preferably it is 0.2 to 10 parts by weight.

Further, in addition to the above vulcanizing agents and vulcanization accelerators, vulcanization accelerating assistants can be added as required. Examples of such vulcanization accelerators include metal oxides such as magnesium oxide and zinc oxide; and organic acids (salts) such as stearic acid, oleic acid and zinc stearate.
And the like, and zinc white and stearic acid are particularly preferable. These vulcanization accelerators can be used alone or in combination of two or more. The amount of the vulcanization accelerator is usually 0.5 to 20 parts by weight based on 100 parts by weight of the total of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber. It is.

On the other hand, as the crosslinking agent, for example, 1,1-
Di-tert-butylperoxy-3,3,5-trimethylcyclohexane, di-tert-butyl peroxide, dicumyl peroxide, tertiary-butylcumyl peroxide, 2,
5-dimethyl-2,5-di (tertiary butyl peroxy)
Organic peroxides such as hexane and 1,3-bis (tertiary butylperoxy-isopropyl) benzene are exemplified. These crosslinking agents can be used alone or in combination of two or more. The amount of the crosslinking agent
Usually, 0.1 to 15 parts by weight, preferably 0.5 to 1 part by weight, based on 100 parts by weight in total of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber.
0 parts by weight.

In addition, a crosslinking aid can be used in combination with the crosslinking agent. Examples of such a crosslinking assistant include sulfur and sulfur compounds such as sulfur and dipentamethylenethiuram tetrasulfide; ethylene di (meth)
Acrylate, polyethylene di (meth) acrylate,
Examples include polyfunctional monomers such as divinylbenzene, diallyl phthalate, triallyl cyanurate, metaphenylene bismaleimide, and toluylene bismaleimide; and oxime compounds such as p-quinone oxime and p, p'-benzoylquinone oxime. These crosslinking assistants can be used alone or in combination of two or more. The compounding amount of the crosslinking aid is usually 0.5 to 20 parts by weight based on 100 parts by weight of the total of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber. .

The rubber composition of the present invention may optionally contain a deterioration inhibitor. As the deterioration inhibitor, for example, octylated diphenylamine, N,
N'-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine,
N, N'-di-β-naphthyl-p-phenylenediamine, N '-(1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, 6-ethoxy-2,2,
4-trimethyl-1,2-dihydroquinoline, 2,6-
Di-tert-butyl-4-methylphenol, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), tris (nonylphenyl) phosphite, 2-mercaptobenzimidazole, 1,3-bis (dimethyl (Aminopyropyl) -2-thiourea, nickel dibutyldithiocarbamate, petroleum wax, paraffin and the like. These deterioration inhibitors may be used alone or
A mixture of more than one species can be used. The amount of the deterioration inhibitor is usually 0.5 to 10 parts by weight, preferably 0.5 to 10 parts by weight based on 100 parts by weight of the total of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber. Is 1-5
Parts by weight.

The rubber composition of the present invention may contain a filler or a softener. Examples of the filler include SRF, FEF, HAF, ISAF, and SRF.
Examples thereof include carbon black such as AF, FT, and MT, and inorganic fillers such as white carbon, fine particle magnesium silicate, calcium carbonate, magnesium carbonate, clay, talc, and titanium oxide. These fillers
They can be used alone or in combination of two or more. The amount of the filler is usually 10 to 150 parts by weight, preferably 20 to 100 parts by weight based on 100 parts by weight of the total of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber. 100 parts by weight. When an inorganic filler is used, a silane coupling agent can be used in combination. Examples of the silane coupling agent include a sulfur compound such as bis (3-triethoxysilylpropyl) tetrasulfide, and γ-mercaptopropyltrimethoxysilane.

Examples of the softener include aromatic oils and naphthenic oils commonly used for rubbers.
Examples include process oils such as paraffin oil, vegetable oils such as coconut oil, and synthetic oils such as alkylbenzene oil. Of these, process oils are preferred. The above softeners can be used alone or in combination of two or more. The amount of the softener is usually 10 to 100 parts by weight based on 100 parts by weight of the total of (A) the ethylene copolymer rubber, (B) the natural rubber, and (C) the polybutadiene rubber.
Parts by weight, preferably 10 to 80 parts by weight.

Further, the rubber composition of the present invention comprises another ethylene / α-olefin / non-conjugated diene copolymer rubber,
One or more other rubbers or resins such as an ethylene / α-olefin copolymer, polyethylene, polypropylene, and conjugated diene rubber can be used as a mixture.

In preparing the rubber composition of the present invention, a conventionally known kneading machine, extruder, vulcanizing apparatus and the like can be used. (A) a vulcanizing agent mixed with an ethylene copolymer rubber or a conjugated diene rubber [(B) natural rubber and (C) polybutadiene rubber] and / or
Alternatively, as a compounding method and a compounding order of a crosslinking agent, a filler, a softener, and the like, for example, using a Banbury mixer or the like, (A) an ethylene copolymer rubber or a conjugated diene rubber [(B) a natural rubber and (C) polybutadiene rubber], a filler, a softener, and the like, and then adding a vulcanizing agent and / or a crosslinking agent using a roll or the like, but is not limited thereto.

Next, vulcanization is carried out by, for example, placing the rubber composition of the present invention in a mold and raising the temperature, or vulcanizing by means of an extrusion molding machine. And vulcanization by heating in a vulcanization tank and vulcanizing, whereby a vulcanized rubber can be produced. The rubber composition of the present invention is suitably used for a tire sidewall application, but is not limited thereto.

[0040]

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these embodiments. The percentages and parts in the examples are on a weight basis unless otherwise specified. The measurement and evaluation in Examples and Comparative Examples were performed by the following methods.

The α-olefin content (mol%) was measured by ¹³ C-NMR method. However, the content (mol%) of ethylene and α-olefin in each of Examples and Comparative Examples is a value when the total amount of these is 100 mol%. The iodine value was measured by an infrared absorption spectrum method. Mooney viscosity (ML _{1 + 4} , 100 ° C. ) Measured at a measurement temperature of 100 ° C., a preheating time of 1 minute, and a measurement time of 4 minutes in accordance with JIS K6300. It was measured by gel permeation chromatography (GPC) in Mw / Mn o-dichlorobenzene at 135 ° C. Glass transition temperature (Tg) The sample was heated to 180 ° C. using a 910 type differential scanning calorimeter manufactured by E.I.
The temperature was measured at a rate of 20 minutes per minute while cooling to -90 ° C. Branching degree index B Sample concentration 0.15% in 135-dichlorobenzene, 135
It measured by 150CV type GPC by Waters company under the conditions of ° C.

Vulcanization Characteristics Test The maximum torque MH was determined from a vulcanization curve at 160 ° C. for 30 minutes using Curastometer-V type manufactured by JSR Corporation. Tensile test According to JIS K6301, a tensile strength TB (MPa) and an elongation at break EB (%) were measured using a No. 3 type test piece at a measuring temperature of 25 ° C. and a tensile speed of 500 mm / min.

Elongation Fatigue Test (Crack Growth) A No. 2 type dumbbell test piece described in JIS K6301 was prepared, and an elongation rate of 50% was obtained for 10 test pieces in which a crack was previously formed in the longitudinal center of the test piece. 7
The specimen was subjected to elongation fatigue under the conditions of 5%, a measurement temperature of 30 ° C., and a rotation number of 300 cpm, and an average value of the number of cycles until the test piece was cut was obtained. Ozone resistance test (static ozone test) Based on JIS K6301, the crack generation time was measured under the conditions of an ozone concentration of 50 pphm, 40 ° C., and an elongation of 40%, and used as an index of ozone resistance. The test period was 14 days. (Dynamic ozone test) According to JIS K6301, ozone concentration 50 pph, 40 ° C, 60 cpm, elongation 30
%, And the crack generation time was measured and used as an index of ozone resistance. The test period was 14 days.

Visco-elasticity characteristics (damping) Using a dynamic analyzer manufactured by Rheometric Scientific, frequency 100 rad / sec
c, damping was measured under the conditions of a temperature of 50 ° C. and a strain of 1%. Resilience Dunlop Using a resilience tester, temperature 50 ℃,
Resilience was measured under conditions at an angle of 45 degrees.

Reference Example 1 (Production of Ethylene Copolymer Rubber) Into a stainless steel autoclave having an internal capacity of 3 liters which had been sufficiently purged with nitrogen, 1.45 liters of purified toluene and 1-liter
1. octene 450 ml, 7-methyl-1,6-octadiene 70 ml, 1,9-decadiene
After adding 5 ml and raising the temperature to 30 ° C., the pressure in the container was adjusted to 5 kg / cm ² while continuously supplying ethylene at a rate of 14 normal liters / minute. Separately from this, the contents are replaced with nitrogen and a magnetic stirrer is inserted.
In a 0 ml glass flask, 3.0 μmol of isopropylene (fluorenyl) (cyclopentadienyl) zirconium dichloride dissolved in 3.0 ml of purified toluene, and 1 μmol of triisobutylaluminum dissolved in 6.0 ml of purified toluene .5 mmol was added and stirred at room temperature for 30 minutes to react. Next, 3.6 μmol of dimethylanilinium tetrakis (pentafluorophenyl) borate dissolved in 7.2 ml of purified toluene was added, and the mixture was stirred at room temperature for 20 minutes to be reacted to obtain a polymerization catalyst. This polymerization catalyst was added to the above autoclave to start polymerization. During the reaction, the polymerization was carried out for 15 minutes while maintaining the temperature at 30 ° C. and continuously supplying ethylene while maintaining the internal pressure of the vessel at 5 kg / cm ² . Next, after a small amount of methanol was added to stop the reaction, the mixture was dissolved by steam stripping and dried with a 6-inch roll to obtain 155 g of a polymer. This polymer had an ethylene content of 71.5 mol%, a 1-octene content of 28.5 mol%, an iodine value of 18,1,9-decadiene content of 0.15 mol%, a Mooney viscosity of 57 and a Mw / Mw /
Mn 5.5, Tg = -68.7 ° C., branching index B = 0.
815 ethylene / 1-octene / 7-methyl-1,6
-Octadiene / 1,9-decadiene copolymer. This ethylene-based copolymer rubber is converted to a copolymer rubber (R
1).

Example 1 (Preparation and evaluation of rubber composition) The copolymer rubber (R1) of Reference Example 1, natural rubber and BR01
[Polybutadiene rubber manufactured by JSR Co., Ltd.] was added at a weight ratio shown in Table 3 to each component obtained by removing the vulcanizing agent component from the components shown in Table 2 using a BR type Banbury mixer (1.7 liters in content). The mixture was kneaded at 70 rpm at 70 ° C. for 180 seconds to obtain a compound (i). Next, the remaining vulcanizing agent components shown in Table 2 were added to the compound (i), and the number of rotations was 60 rpm using a BR type Banbury.
The mixture was kneaded at 70 ° C. for 1 minute to obtain a compound (ii).
Next, the compound (ii) was heated by a hot press heated to 160 ° C. under a pressure of 150 kgf / cm ² for 15 minutes to prepare test pieces for each adjustment, and various characteristics were evaluated. As a result, the composition using the copolymer rubber (R1) of Reference Example 1 was excellent in the balance between ozone resistance and fatigue resistance. Table 3 shows the evaluation results.

Reference Example 2 (Production of Ethylene Copolymer Rubber) 1.9 liters of purified toluene and 7-liter were placed in a 3 liter stainless steel autoclave sufficiently purged with nitrogen.
50 ml of methyl-1,6-octadiene,
1.7 ml of 1,9-decadiene and 18 mmol of methylaluminoxane in terms of aluminum atom dissolved in 15 ml of purified toluene were added, and the mixture was added at 30 ° C.
After the temperature was raised to 12 normal liters /
The pressure inside the container was adjusted to 5 kg / cm ² while continuously supplying propylene at a rate of 12 normal liters / minute. Then dimethylsilyl (t-butylamide) (2,3,4,5) dissolved in 4.5 ml of toluene
2.5 μmol of -1-tetramethylcyclopentadienyl) zirconium dichloride was added to initiate the polymerization. During the reaction, the temperature was kept at 30 ° C., and while the monomer was continuously supplied, the internal pressure of the vessel was kept at 5 kg / cm ² ,
The reaction was performed for 5 minutes. After the reaction was stopped by adding a small amount of methanol, the mixture was dissolved by steam stripping and dried with a 6-inch roll to obtain 121 g of a polymer. This polymer has an ethylene content of 70 mol%, a propylene content of 30 mol%, an iodine value of 15,1,9-decadiene content of 0.11 mol%, a Mooney viscosity of 75, Mw /
Mn 4.5, Tg = -58.7 ° C., branching index B = 0.
855 ethylene / propylene / 7-methyl-1,6-
Octadiene / 1,9-decadiene copolymer.
This ethylene-based copolymer rubber is used as a copolymer rubber (R2)
And

Example 2 (Preparation and evaluation of rubber composition) Example 1 was repeated except that the copolymer (R2) of Reference Example 2 was used.
Preparation of compound (i) and compound (ii), and evaluation of various properties were performed in the same manner as in. As a result, the composition using the copolymer rubber was excellent in the balance between ozone resistance and fatigue resistance. Table 3 shows the evaluation results.

Comparative Examples 1 to 3 Instead of the copolymer of Example 1, EP33 (EPDM, manufactured by JSR Corporation), EP24 (EPDM, manufactured by JSR Corporation), BR01 (EPDM) And polybutadiene rubber), and compositions with natural rubber were produced, and various properties were evaluated in the same manner as in Example 1. Table 3 shows the evaluation results as Comparative Examples 1 to 3.
Shown in

Example 3 The copolymer rubber (R1) of Reference Example 1, natural rubber and BR01
[Polybutadiene rubber manufactured by JSR Co., Ltd.] was added at a weight ratio shown in Table 5 to each component obtained by removing the vulcanizing agent component from the components shown in Table 4 using a BR type Banbury mixer (1.7 liters in content). The mixture was kneaded at 70 rpm at 70 ° C. for 180 seconds to obtain a compound (i). Next, the remaining vulcanizing agent components shown in Table 4 were added to the compound (i), and the number of rotations was 60 rpm using a BR type Banbury.
The mixture was kneaded at 70 ° C. for 1 minute to obtain a compound (ii).
Next, the compound (ii) was heated by a hot press heated to 160 ° C. under a pressure of 150 kgf / cm ² for 15 minutes to prepare test pieces for each adjustment, and various characteristics were evaluated. As a result, the composition using the copolymer rubber (R1) of Reference Example 1 was excellent in the balance between ozone resistance and fatigue resistance. Table 5 shows the evaluation results.

Example 4 A rubber composition and a vulcanized rubber were obtained in the same manner as in Example 3 except that (A) the copolymer rubber (R2) of Reference Example 2 was used as the ethylene copolymer rubber. Was. Table 5 shows the results.

Comparative Examples 4 and 5 EP33 [EPDM, manufactured by JSR Corporation] was used instead of the copolymer of Example 3 (Comparative Example 4).
Using only BR01 (polybutadiene rubber manufactured by JSR Co., Ltd.) (Comparative Example 5), compositions with natural rubber were produced, and various properties were evaluated in the same manner as in Example 3. The evaluation results are shown in Table 5 as Comparative Examples 4 and 5.

[0053]

[Table 1]

[0054]

[Table 2]

* 1) RSS # 1 * 2) Tokai Carbon Co., Ltd., Seat SO * 3) Fujikosan Co., Ltd., Fukkol AROMAX # 5 * 4) N-phenyl-N'-isopropyl-p-phenylene Diamine * 5) Seiko Chemical Co., Ltd., Suntite Z * 6) Nt-butyl-2-benzothiazolesulfenamide

[0056]

[Table 3]

Natural rubber: RSS # 1 EP33: manufactured by JSR Co., Ltd., EPDM (diene type: ENB) EP24: manufactured by JSR Co., Ltd., EPDM (diene type: ENB) BR01: manufactured by JSR Co., Ltd. Polybutadiene rubber

[0058]

[Table 4]

* 1) RSS # 1 * 2) BR01 * 3) Nippon Silica Co., Ltd., Nipsil AQ * 4) Degussa Co., Ltd., Si69 * 5) Fujikosan Co., Ltd. Fukkor FLEX # 205
0N * 6) rutile type * 7) 1,3-bis (dimethylaminopropyl) -2
-Thiourea * 8) Nt-butyl-2-benzothiazolesulfenamide * 9) Santite Z manufactured by Seiko Chemical Co., Ltd. * 10) Diphenylguanidine * 11) Nt-butyl-2-benzothiazolesulfen Amide

[0060]

[Table 5]

[0061]

The rubber composition of the present invention can be used to convert a specific ethylene copolymer rubber excellent in co-vulcanizability with a conjugated diene rubber and processing characteristics into natural rubber and polybutadiene rubber in an appropriate composition range. By blending, it has an excellent balance between fatigue resistance and ozone resistance without impairing the inherent damping characteristics of conjugated diene rubbers such as natural rubber and polybutadiene rubber, and is particularly useful for tire sidewall applications.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Akima 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Corporation (72) Inventor Fumio Tsutsumi 2-11-24 Tsukiji, Chuo-ku, Tokyo J F-term in SR Inc. (reference) 4J002 AC01X AC03Y BB15W GN01

Claims (2)

[Claims] (A) ethylene, α- having 3 to 12 carbon atoms
Olefin and C7 represented by the following structural formula (I)
Ethylene copolymer rubber 10 obtained by polymerizing a monomer component having a main component of from 30 to 30 linear or branched non-conjugated polyene and satisfying the following requirements (1) to (6): ６０60 parts by weight, (B) 10-80 parts by weight of natural rubber,
And (C) 10 to 70 parts by weight of polybutadiene rubber (provided that (A) + (B) + (C) = 100 parts by weight). Structural formula (I); (Wherein X is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ is an alkyl group having 1 to 8 carbon atoms. (Except when both R ¹ and R ² are hydrogen atoms.) (1) The molar ratio of ethylene to α-olefin having 3 to 12 carbon atoms (ethylene / α-olefin) is 40/60 to 9
(2) iodine value is in the range of 5-45, (3) Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 15-3.
(4) Gel permeation chromatography (GP
C), the weight average molecular weight in terms of polystyrene (M
w) and the number average molecular weight (Mn) in terms of polystyrene (Mw / Mn) are in the range of 2.5 to 15, and (5) the glass transition temperature (Tg) obtained by differential scanning calorimetry (DSC) is (6) The branching degree index B is in the range of 0.60 to 0.95. 2. The rubber composition according to claim 1, wherein (A) an α, ω-diene represented by the following structural formula (II) is further contained as a monomer component constituting the ethylene copolymer rubber. Structural formula _{(II); CH 2 = CH-} (CH 2) m -CH = CH 2 ( wherein, m is an integer of from 1 to 10.)