JP2004285336A - Compatibilizer and rubber composition using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the interface affinity between a rubber component and a rubber reinforcing agent such as carbon / silica by a unique microstructure composition of high cis-high vinyl polybutadiene, or to improve the interface affinity by compatibilization between rubber components. To improve the compatibility and improve the rubber reinforcing effect or the physical properties of the rubber composition for tires.
A compatibilizer comprising a modified high cis-high vinyl polybutadiene obtained by modifying a high cis-high vinyl polybutadiene produced by a metallocene catalyst in the presence of a transition metal catalyst.
[Selection diagram] None

Description

  TECHNICAL FIELD The present invention relates to a compatibilizing agent for a rubber composition comprising a novel high cis-high vinyl polybutadiene and a rubber composition using the same.

    Polybutadiene has, as a so-called microstructure, a bonding part (1,4-structure) formed by polymerization at the 1,4-position and a bonding part (1,2-structure) formed by polymerization at the 1,2-position. Coexist in the molecular chain. The 1,4-structure is further divided into two types, a cis structure and a trans structure. On the other hand, the 1,2-structure has a structure having a vinyl group as a side chain.

  It is known that polybutadienes having different microstructures are produced by a polymerization catalyst, and are used for various applications depending on their properties.

  As disclosed in JP-A-9-291108 (Patent Document 1) and the like, 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 is used. It has been found by the present applicant that a polybutadiene having a microstructure containing a suitable 1,2-structure in the high cis structure, a small trans structure, and a high molecular linearity (linearity) can be produced. . Since this polybutadiene has excellent properties, application to impact-resistant polystyrene resins and tires is being studied.

  JP-A-11-49924 (Patent Document 2) describes the application of a composition comprising a specific high cis-high vinyl polybutadiene to tires, which is useful for tread applications, has a high rebound resilience and skid resistance. Is described.

  In addition, the high cis-high vinyl BR (hereinafter, HC-HVBR) produced with the above-mentioned metallocene catalyst has a microstructure having a moderate 1,2-structure in the high cis structure, a small trans structure, and a molecular linearity. Although it is a polybutadiene having a high (linearity), it shows a relatively high cold flow, so that improvement in storage and transportation may be required in some cases.

JP-A-9-291108 JP-A-11-49924

  High cis-high vinyl polybutadiene has a unique microstructure composition that improves the affinity between the rubber component and a rubber reinforcing agent such as carbon or silica, or that improves the interfacial affinity by compatibilization between the rubber components. To improve the rubber reinforcing effect or the physical properties of the rubber composition for tires.

  The present invention relates to a compatibilizer comprising a modified high cis-high vinyl polybutadiene obtained by modifying a high cis-high vinyl polybutadiene produced by a metallocene catalyst in the presence of a transition metal catalyst.

  In addition, the present invention provides that the high cis-high vinyl polybutadiene has a 1,2-structural unit content of 4 to 30 mol%, a cis-1,4-structural unit content of 65 to 95 mol%, and trans-1,4 -The compatibilizer described above, which is a polybutadiene having a structural unit content of 5 mol% or less.

  The present invention also relates to a rubber composition comprising 0.1 to 20% by weight of a high cis-high vinyl polybutadiene and 80 to 99.9% by weight of a rubber reinforcing agent.

  The present invention also relates to a rubber composition using 1 to 100 parts by weight of the rubber composition and 1 to 100 parts by weight of the rubber.

  The present invention also relates to a tire rubber composition comprising the above rubber composition.

  INDUSTRIAL APPLICABILITY According to the present invention, an improved affinity between a rubber component and a rubber reinforcing agent such as carbon silica due to a unique microstructure composition of a modified high cis-1,4-polybutadiene (HCHV) having improved cold flow property of rubber is provided. Alternatively, the compatibility is improved by improving the interfacial affinity by compatibilization between the rubber components, thereby improving the rubber reinforcing effect or the physical properties of the rubber composition for tires.

  The (a) high cis-high vinyl polybutadiene (hereinafter referred to as “HC-HVBR”) of the present invention has a cis-1,4-structural unit content in the microstructure of 65 to 95 mol%, preferably 70 to 90 mol%. %, And the content of the 1,2-structural unit is 4 to 30 mol%, preferably 5 to 25 mol%, and more preferably 7 to 15 mol%. Further, the content of the trans-1,4-structural unit is preferably 5 mol% or less, particularly preferably 0.5 to 4.0 mol%.

Also, it is preferable that (a) the relational expression between the 5% styrene solution viscosity (St-cp) of HC-HVBR at 25 ° C. and the Mooney viscosity (ML _{1 + 4} ) satisfies the following expression (I).
1 ≦ St-cp / ML _{1 + 4} ≦ 7. . . (I)
Particularly preferably, 2 ≦ St-cp / ML _{1 + 4} ≦ 6 is satisfied.

  Further, the toluene solution viscosity (Tcp) of HC-HVBR is preferably from 20 to 500, and particularly preferably from 30 to 300.

The Mooney viscosity (ML _{1 + 4} ) of the HC-HVBR of the present invention is preferably from 10 to 200, particularly preferably from 25 to 100.

  The molecular weight of HC-HVBR is preferably from 0.1 to 10, particularly preferably from 0.1 to 3, as the intrinsic viscosity [η] measured in toluene at 30 ° C.

Further, the molecular weight of HC-HVBR 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 × 10 ⁵ , more preferably 1 × 10 ⁵ to 10 × 10 ⁵

  Moreover, the molecular weight distribution (Mw / Mn) of the HC-HVBR of the present invention is preferably 1.5 to 3.5, more preferably 1.6 to 3.

The (a) HC-HVBR is, for example,
It can be produced by polymerizing butadiene using (A) a metallocene complex of a transition metal compound, and (B) a catalyst obtained from an ionic compound of a non-coordinating anion and a cation and / or an 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) Water
Can be produced by polymerizing butadiene using a catalyst obtained from

  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 belonging to Group 4 of the periodic table such as titanium or zirconium (for example, CpTiCl ₃ ), a metallocene complex of a transition metal belonging to Group V of the periodic table such as vanadium, niobium, or tantalum; Group 6 transition metal metallocene-type complexes, and metallocene type complexes of Group VIII transition metals such as cobalt and nickel are exemplified.

  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:
(1) RM · La, that is, a transition metal compound of Group 5 of the Periodic Table having an oxidation number of +1 having a ligand of a cycloalkadienyl group (2) R _n MX _2-n · La, ie, at least one Transition metal compound belonging to Group 5 of the periodic table having an oxidation number of +2 and having a ligand of a cycloalkadienyl group of the formula (3): R _n MX _3-n · La
(4) RMX ₃・ La
(5) RM (O) X ₂・ La
(6) R _n MX _3-n (NR ′)
(Wherein n is 1 or 2, a is 0, 1 or 2).

Among _{them, RM · La, R n MX} 2-n · La, R 2 M · La, RMX 3 · La, etc. RM (O) X ₂ · La are preferably exemplified.

  M is preferably a transition metal compound of Group 5 of the periodic table.

As the metallocene complex of the transition metal compound (A) of Group 5 of the periodic table, a vanadium compound in which M is vanadium is preferable. For example, RV · La, RVX · La , R 2 M · La, RMX 2 · La, RMX 3 · La, etc. RM (O) X ₂ · La are preferably exemplified. Particularly, RV · La and RMX ₃ · La are preferred.

Specific examples of the compound represented by RMX ₃ .La include the following. Cyclopentadienyl vanadium trichloride is exemplified.

Specific compounds represented by RM (O) X ₂ include cyclopentadienyloxovanadium dichloride, methylcyclopentadienyloxovanadium dichloride, benzylcyclopentadienyloxovanadium dichloride, (1,3-dimethylcyclohexane). (Pentadienyl) oxovanadium dichloride.

  Examples of the non-coordinating anion constituting the ionic compound of the non-coordinating anion and the cation as the component (B) include, for example, tetra (phenyl) borate and tetra (fluorophenyl) borate. Can be

  On the other hand, examples of the cation include a trisubstituted carbonium cation such as a triphenylcarbonium cation.

  Further, alumoxane may be used as the component (B). The alumoxane is obtained by contacting an organic aluminum compound 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, including those partially substituted with a halogen atom and / or an alkoxy group. N is the degree of polymerization and is 5 or more, preferably 10 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.

  Typical examples of the condensing agent include water, and in addition thereto, any condensing agent capable of condensing the trialkylaluminum, for example, adsorbed water such as inorganic substances, diol, and the like.

  The conjugated diene may be polymerized by combining the component (A) and the component (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.

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

When an ionic compound is used as the component (B), the above alumoxane may be used in combination as the component (C).
The order of adding the catalyst components is not particularly limited.

  In the present invention, it is preferable to further add water as the component (D) as the catalyst system. 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 5, more preferably from 0.7 to 1.5. .

  At the time of polymerization, hydrogen can be allowed to coexist if necessary.

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

  The polymerization method is not particularly limited, and solution polymerization or bulk polymerization using 1,3-butadiene itself as a polymerization solvent can be applied. Aromatic hydrocarbons such as toluene, benzene and xylene, aliphatic hydrocarbons such as n-hexane, butane, heptane and pentane, alicyclic hydrocarbons such as cyclopentane and cyclohexane, 1-butene and 2-butene Examples include hydrocarbon solvents such as olefin hydrocarbons, mineral spirits, solvent naphtha, and kerosene, and halogenated hydrocarbon solvents such as methylene chloride.

  Further, as the component (a), a mixture of a low molecular weight HC-HVBR (a1) component and a high molecular weight HC-HVBR (a2) component may be used.

As a method of adjusting the molecular weight in the present invention, there is a method of polymerizing a conjugated diene compound in the presence of a chain transfer agent such as hydrogen using the above-mentioned catalyst.

  After the polymerization reaction achieves a predetermined polymerization rate, a transition metal catalyst is added and reacted to modify the polymer chain.

  Examples of the transition metal compound in the transition metal catalyst include a titanium compound, a zirconium compound, a vanadium compound, a chromium compound, a manganese compound, an iron compound, a ruthenium compound, a cobalt compound, a nickel compound, a palladium compound, a copper compound, a silver compound, and a zinc compound. No. Among them, a cobalt compound is particularly preferable.

  The transition metal catalyst of the present invention is preferably a system comprising a transition metal compound, organoaluminum, and water.

  As the cobalt compound, a salt or complex of cobalt is preferably used. Particularly preferred are cobalt salts such as cobalt chloride, cobalt bromide, cobalt nitrate, cobalt octylate, cobalt naphthenate, cobalt versatate, cobalt acetate, cobalt malonate, and bisacetylacetonate and trisacetylacetonate of cobalt. And organic base complexes such as triarylphosphine complex, trialkylphosphine complex, pyridine complex and picoline complex of cobalt acetoacetate and cobalt halide, and ethyl alcohol complex.

  Of these, cobalt octylate, cobalt naphthenate, cobalt versatate, bisacetylacetonate and trisacetylacetonate of cobalt are preferred.

Examples of the organoaluminum include trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, trialkylaluminum such as tridecylaluminum, dimethylaluminum chloride, dimethylaluminum bromide, diethylaluminum chloride, diethylaluminum bromide Dialkyl aluminum halides such as diethyl aluminum iodide, dibutyl aluminum chloride, dibutyl aluminum bromide, dibutyl aluminum iodide, methyl aluminum sesquichloride, methyl aluminum sesquibromide, ethyl aluminum sesquichloride, ethyl aluminum sesquibromide, etc. Kill sesqui aluminum halides, methyl aluminum dichloride, methyl aluminum dibromide, ethyl aluminum dichloride, ethyl aluminum dibromide, butyl aluminum dichloride, monoalkyl aluminum halide such as butyl aluminum dibromide and the like. These may be used alone, or a plurality of them may be selected and mixed. Among them, diethyl aluminum chloride is preferably used.

In the transition metal catalyst of the present invention, the amount of the cobalt compound to be added may be in any range depending on the desired degree of branching, but is preferably 1 × 10 ⁻⁷ to 1 × 10 ⁷ per 1 mol of polybutadiene. ^-3 mol, particularly preferably 5 × 10 ^-7 to 1 × 10 ^-4 mol.

Depending on the desired degree of branching, the amount of organoaluminum can be in any range, but is preferably 1 × 10 ^{−5 to} 5 × 10 ⁻² mol per 1 mol of polybutadiene, particularly preferably 1 mol of organoaluminum. It is from 5 × 10 ⁻⁵ to 1 × 10 ⁻² mol.

  The amount of water added in the branching reaction can be in any range depending on the desired degree of branching, but is preferably 1.5 mol or less, and particularly preferably 1 mol or less, per 1 mol of the organoaluminum compound. .

  After performing polymerization for a predetermined time, after terminating the polymerization by injecting a terminating agent such as alcohol, the inside of the polymerization tank is released as necessary, and post-treatments such as washing and drying steps are performed.

Beam at 100 ° C. toluene solution viscosity (Tcp) of the resulting modified polybutadiene in the present invention - D - viscosity (ML _{1 + 4)} ratio (Tcp / ML _{1 + 4)} is preferably from 0.9 to 3.5 And more preferably 1.2 to 2.5.

The toluene solution viscosity (Tcp) of the modified polybutadiene obtained in the present invention is preferably 30 to 300, and more preferably 45 to 200.

  Further, the cold flow rate (CF) of the modified polybutadiene obtained by the present invention is preferably less than 20, and particularly preferably less than 15.

The modified polybutadiene obtained in the present invention has a Mooney viscosity (ML _{1 + 4} ) at 100 ° C. of preferably 10 to 200, particularly preferably 25 to 100.

As the rubber reinforcing agent of the present invention, in addition to various carbon blacks, white carbon, activated calcium carbonate, inorganic reinforcing agents such as ultrafine magnesium silicate, polyethylene resin, polypropylene resin, high styrene resin, phenol resin, lignin, modified There are organic reinforcing agents such as melamine resin, coumarone indene resin and petroleum resin. Particularly preferred is carbon black having a particle diameter 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.

  In the present invention, the ratio of the rubber composition comprising HC-HVBR and the rubber reinforcing agent is preferably composed of 0.1 to 20% by weight of HC-HVBR and 80 to 99.9% by weight of the rubber reinforcing agent. In particular, 1 to 10% by weight of HC-HVBR and 90 to 99% by weight of a rubber reinforcing agent are preferable.

  In the present invention, the rubber to be mixed with the above rubber composition includes natural rubber, high cis-polybutadiene, low cis-polybutadiene, styrene-butadiene rubber, polyisoprene, isoprene rubber such as isoprene-isobutylene copolymer, and chlorinated butyl rubber. , Brominated butyl rubber, acrylonitrile-butadiene rubber, and the like. Among them, natural rubber and high cis-polybutadiene are preferred. Epoxy-modified, silane-modified or maleated rubbers are also used.

  The ratio of the rubber composition to the rubber is preferably 1 to 100 parts by weight of the rubber composition and 1 to 100 parts by weight of the rubber, and particularly preferably 40 to 80 parts by weight of the rubber composition and 40 to 80 parts by weight of the rubber.

  The rubber composition 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.

  The rubber composition of the present invention, if necessary, kneading 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.

  As the vulcanizing agent, known vulcanizing agents, for example, 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, and xanthates are 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.

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

  As the process oil, any of an aromatic type, a naphthenic type, and a paraffin type may be used.

  The rubber composition of the present invention has improved properties such as improved wear resistance and reduced heat build-up, and is used as a rubber composition suitable for applications such as tread and sidewall of a more highly balanced tire. Can be

(Reference Example 1) (Production of high cis-high vinyl polybutadiene)
3.5 L of a toluene solution (1.3-butadiene: 814 g) containing 30 wt% of 1.3-butadiene is charged and stirred in a 5 L autoclave with a stirrer purged with nitrogen. Next, hydrogen gas was introduced to raise the pressure by 0.092 kgG / cm ² . Over a period of 3 minutes at 30 ° C, 2.25 mmol of triethylaluminum, 0.039 mmol of trityltetra (perfluorophenyl) borate and 0.026 mmol of cyclopentadienyl vanadium trichloride were successively added. Polymerization was performed for minutes. Further, 4.8 ml of toluene containing 300 mg / L of water, 0.1 ml of a toluene solution of 1 mol / L of diethyl aluminum chloride (DEAC), and 0.5 ml of a toluene solution of 5 mmol / L of cobalt octylate (Co (Oct) ₂ ) were added. At 40 ° C. for 30 minutes.
After the polymerization, the reaction was stopped by injecting an equivalent mixture of ethanol and heptane containing 2,6-di-tert-butyl-p-cresol, and the solvent was evaporated and dried. The yield of the obtained polymer was 32%, and the microstructure, Mooney viscosity, and 5% toluene solution viscosity were as shown in Table 1. It was shown to.

(Reference Example 2) (Production of high cis-high vinyl polybutadiene)
3.5 L of a toluene solution (1.3-butadiene: 814 g) containing 30 wt% of 1.3-butadiene is charged and stirred in a 5 L autoclave with a stirrer purged with nitrogen. Next, hydrogen gas was introduced. Over a period of 3 minutes at 30 ° C, 2.25 mmol of triethylaluminum, 0.039 mmol of trityltetra (perfluorophenyl) borate and 0.026 mmol of cyclopentadienyl vanadium trichloride were successively added. Polymerization was performed for minutes.
After the polymerization, the reaction was stopped by injecting an equivalent mixture of ethanol and heptane containing 2,6-di-tert-butyl-p-cresol, and the solvent was evaporated and dried. The yield of the obtained polymer was 32%, and the microstructure, Mooney viscosity, and 5% toluene solution viscosity were shown in the table.

  UBEPOL (150L and 150B) manufactured by Ube Industries, Ltd. was used as the high cis-polybutadiene.

  As the natural rubber, a rubber that had been adjusted to ML = 70 by mastication was used.

(Examples 1 to 3) (Comparative Examples 1 to 3)
A rubber composition comprising high cis-high vinyl polybutadiene (HC-HVBR), high cis polybutadiene and natural rubber of Reference Example 1 was blended and vulcanized according to the blending recipe shown in Table 1 by the following method. Each characteristic is shown in the table.

Evaluation items and implementation conditions Kneading method Kneading is performed according to the following procedure.
[Primary formulation]
Kneading device: Banbury mixer (1.7L capacity)
Rotation speed: 77 rpm
Start temperature: 90 ° C
Kneading procedure:
0 minutes; rubber input 1 minute; filler input 3 minutes; raise ram and clean (15 seconds)
5 min; Dump The dump material was continuously wound on a 10-inch roll for 1 minute, rounded three times, and then discharged. After the compound was cooled for 2 hours or more, secondary compounding was performed according to the following procedure.

[Secondary formulation]
After the completion of the primary blending, a secondary blending was performed according to the following procedure.
Kneading device: 10 inch roll Roll temperature: 40-50 ° C
Roll gap: 2mm
Kneading procedure:
(1) 0 minutes; winding of dump material and feeding of sulfur / vulcanization accelerator (2) 2 minutes; turning back (3) 3 minutes;

Vulcanization time
Measuring device: JSR Curastometer 2F type
Measurement temperature: 150 ° C
Measurement time; t ₉₀ × 2, × 3 was taken as the vulcanization time.
Vulcanization conditions
Vulcanization equipment; press vulcanization
Vulcanization temperature: 150 ° C

[Evaluation of rubber properties]
Microstructure was performed by infrared absorption spectroscopy. The microstructure was calculated from the absorption intensity ratio of cis 740 cm ^-1 , trans 967 cm ^-1 , and vinyl 910 cm ^-1 .

[Η] was measured at a temperature of 30 ° C. in a toluene solution.
Mooney viscosity (ML _{1 + 4} ) was measured according to JIS K6300.

  Toluene solution viscosity (Tcp) was determined by dissolving 2.28 g of polymer in 50 ml of toluene, and using a standard solution for calibration of a viscometer (JIS Z8809) as a standard solution. It was measured at 25 ° C. using a 400.

[Compound physical properties]
Die swell
Measuring device: Monsanto processability measuring device (MPT)
Die shape; circular
L / D; 1, 10 (D = 1.5 mm)
Measurement temperature; 100 ° C
Shear rate; 10,100 sec ^-1

Mooney viscosity was measured according to the measurement method specified in JIS-K-6300.
The mixture is immersed and extracted in toluene at room temperature for 1 day, and the remaining insoluble matter is dried under reduced pressure at 70 ° C. for 1 hour.
Carbon gel (%) = (dry weight of remaining insoluble matter / weight of blend) × 100

[Vulcanized physical properties]
The hardness, rebound resilience, and tensile strength were measured according to a measurement method specified in JIS-K-6301.

  The tan δ of the dynamic viscoelasticity was measured using RSA2 manufactured by Rheometrics Inc. under the conditions of a temperature of 70 ° C., a frequency of 10 Hz and a dynamic strain of 2%.

Exothermic Characteristics Measured using a Goodrich Flexometer in accordance with ASTM-D623 under the conditions of a strain of 0.175 inches, a load of 55 pounds, and 100 ° C. for 25 minutes.

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

As is clear from the above examples, the NR / BR rubber component physically and chemically adsorbed on carbon increases due to the effect of compatibilization of HC-HVBR (increase in the amount of carbon gel), and thus various physical properties of the vulcanized product. Is improved. (Decrease in wear resistance and heat generation)

Claims (5)

A compatibilizer comprising a modified high cis-high vinyl polybutadiene obtained by modifying a high cis-high vinyl polybutadiene produced by a metallocene catalyst in the presence of a transition metal catalyst. The high cis-high vinyl polybutadiene has a 1,2-structural unit content of 4 to 30 mol%, a cis-1,4-structural unit content of 65 to 95 mol%, and a trans-1,4-structural unit content of 5 The compatibilizer according to claim 1, wherein the polybutadiene is not more than mol%. A rubber composition comprising 0.1 to 20% by weight of the modified high cis-high vinyl polybutadiene according to claim 1 and 80 to 99.9% by weight of a rubber reinforcing agent. A rubber composition comprising 1 to 100 parts by weight of the rubber composition according to claim 3 and 1 to 100 parts by weight of rubber. A rubber composition for a tire, comprising the rubber composition according to claim 3.