JPH09151277A - Diene polymer rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a diene polymer rubber compsn. exhibiting little strain- dependence of hysteresis loss and improved in abrasion resistance, low heat- build-up properties, breaking strengths, and processibility by incorporating a branched diene polymer and a specific linear diene polymer into the same. SOLUTION: This compsn. contains 15wt.% or higher branched diene polymer having a vinyl bond content of butadiene parts before hydrogenation of 15-60wt.%, a Mooney viscosity (ML1+4 , 100 deg.C) of 10-150 and a degree of hydrogenation of 30% or lower and 15wt.% or higher linear diene polymer having a vinyl bond content of butadiene parts before hydrogenation of 20-70wt.%, a Money viscosity (ML1+4 , 100 deg.C) of 10-150, a degree of hydrogenation of 30% or lower, and at least one kind of functional group selected from among a group of formula I (R<1> is an alkyl, aryl, aralkyl, alkenyl, or ester group; and M is Si, Ge, or Sn), a (thio)carbonyl group, a group of formula II (R<2> is an alkyl, aryl, aralkyl, alkoxy, or ester group), a group of formula III (Y is O or S), and amide, imino, triazine, (thio)carboxyl, and amino groups.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in wear resistance, low exothermicity, breaking strength and workability, and has a small pain effect.
The present invention relates to a diene polymer rubber composition suitable for tires, belts, and the like, and more specifically, a branched diene polymer having a branched structure of 3 or more branches in the molecular chain and modified with a specific functional group in the molecular chain. And a linear diene-based polymer as described above.

2. Description of the Related Art In recent years, the durability and longevity of rubber members have been increasingly demanded, and it has become important to improve the properties of rubber such as wear resistance, low heat generation, and workability. It was Conventionally, polybutadiene has been known as a rubber-like polymer having excellent wear resistance. In addition, Tokiko Sho 4
8-30151, JP-A-52-96695, and JP-A-60-252643 disclose multibranched non-hydrogenated or hydrogenated conjugated diene copolymers. However, compounds such as silicon tetrachloride and divinylbenzene for making the copolymer hyperbranched have low affinity with compounding agents such as carbon, and are still insufficient in terms of carbon dispersion and carbon reinforcement. Properties, wear resistance, low heat buildup, and breaking strength have not been sufficiently improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical problems, and is a rubber composition excellent in low exothermic property, breaking strength, abrasion resistance and workability and having a small Payne effect. The purpose is to provide things. here,
The small Payne effect means that the strain dependence of hysteresis loss is small, and therefore, in the practical deformation region, the heat generation is further smaller, which means that the deterioration of the product is prevented and the life is greatly improved.

Means for Solving the Problems As a result of intensive studies on the diene polymer having a branched structure, the present inventors have found that it is a branched diene polymer having a branched structure of 3 or more branches in the molecular chain. By containing a linear diene-based polymer having a specific functional group in the molecular chain, the processability is good, the heat generation can be controlled, the durability and breaking properties are excellent, and the Pain effect is small. The inventors have found that a polymer rubber composition can be obtained, and arrived at the present invention.
That is, according to the present invention, as a rubber component, at least 15% by weight of a branched diene-based polymer (A) and at least one functional group selected from the groups (a) to (b) below in the molecular chain. At least 15% by weight of a linear diene polymer (B) having a vinyl bond content of 20% by weight or more
And the hydrogenation rates of the branched diene polymer (A) and the linear diene polymer (B) are each 30%.
The present invention provides a diene-based polymer rubber composition characterized by being below. (B) R 1 ³ _M group (wherein, R ¹ is an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group or an ester group, M is silicon atom, a germanium atom or a tin atom.) ( b) (thio) carbonyl group ^(c) _{R 2} 2 P- group (wherein, ^{R 2} is an alkyl group, an aryl group, an aralkyl group, an alkoxy group or an ester group.) (d) (Here, Y is an oxygen atom or a sulfur atom, and R ² is the same as above.) (E) Amido group (f) Imino group (to) Triazine group (thi) (thio) carboxyl group (ri) amino group First, The branched diene-based polymer (A) of the present invention has a branched structure of three or more branches in the molecular chain, whereby the composition obtained at the beginning has good low-temperature flow characteristics and good processability. Not only is it excellent in breaking strength. Particularly, in order to improve the rolling friction resistance of the obtained rubber composition, 30 to 80% by weight, preferably 40 to 70% by weight, of the branched diene polymer of the present invention is used.
Is preferably constituted by a tin-carbon bond or a polyisocyanate coupling. The proportion of the branched diene polymer (A) contained in the diene polymer rubber composition of the present invention is 15% by weight or more, preferably 30%.
It is -80% by weight, and if it is less than 15% by weight, the tensile properties are inferior, which is not preferable. Furthermore, the hydrogenation rate of the branched diene polymer (A) is less than 30%. However, in the present invention, the hydrogenation rate of the branched diene polymer (A) may be 0%, but when the hydrogenation rate of the linear diene polymer (B) is 0%, The hydrogenation rate of the branched diene polymer (A) is greater than 0%. The branched diene polymer (A) used in the present invention has a polymodal molecular weight distribution. Here, polymodal is
It means that the molecular weight distribution by gel permeation chromatography (GPC) gives a pattern in which peaks are observed at two or more points, and is usually 2-3 peaks. When the high molecular weight region is a branched polymer having at least trifunctionality, the molecular weight distribution is widened, which is preferable in view of processability. Next, the linear diene polymer (B) of the present invention
Has at least one functional group selected from the above (a) to (i) in its molecule. Examples of the compound forming the functional groups (a) to (i) include the following compounds. These compounds may be used alone or in combination of two or more. That is, as the compound (a) forming the R ¹ ₃ M group, the compound represented by the general formula R ¹ ₃ MX (wherein R ¹ has ¹ carbon atom)
To C18 alkyl group, C6 to C18 aryl group, allyl group, C7 to C18 aralkyl group, C2 to C1
8 is an alkenyl group, an aliphatic ester group having 1 to 18 carbon atoms or an aromatic ester group having 6 to 18 carbon atoms, M is a silicon atom, a germanium atom or a tin atom, X
Is a halogen atom or an ester group. ), Specifically, monochlorotrimethyltin, monobromotrimethyltin, triphenyltin monochloride, tributyltin chloride, trimethylsilyl chloride, triphenylsilyl chloride, triphenylgermyl chloride, tributyltin stearate, Examples include triphenyl tin laurate. As the compound forming the (b) (thio) carbonyl group, a compound represented by the general formula: (However, R ¹ is the same as above, Y is an oxygen atom or a sulfur atom, and X ′ is a halogen atom.) Specifically, acetyl chloride, benzoyl chloride, p-dimethylaminobenzoyl chloride. ,
p-dimethylaminothiobenzoyl chloride and the like. ^(C) _{R 2} 2 P- group (wherein, ^{R 2} is an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, 7 carbon atoms
And an aralkyl group having 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aliphatic ester group having 6 to 18 carbon atoms, or an aromatic ester group having 7 to 18 carbon atoms. The compound forming () is, for example, a compound represented by the general formula R ² ₂ PX (R ² and X are the same as defined above), and specific examples thereof include diphenylphosphine chloride and dioctylphosphine chloride. (D) Examples of the compound forming (wherein Y is an oxygen atom or a sulfur atom and R ² is the same as above) include, for example, a compound represented by the general formula: (Wherein R ² , Y and X are the same as above), and specifically include diphenylchlorophosphate (diphenylphosphine oxide) and the like. (V) The compound forming an amide group is represented by, for example, the general formula R ³ NCO (wherein R ³ represents an alkyl group having 1 to 8 carbon atoms and an aromatic group having 6 to 14 carbon atoms). It is a compound, and specific examples thereof include methyl isocyanate, octyl isocyanate, phenyl isocyanate, and phenyl isothiocyanate. (F) The compound forming an imino group is, for example, a compound represented by the general formula R ¹ -C = N (where R ¹ is the same as above), and specifically, acetonitrile, benzonitrile, N- Examples include phenylmaleimide. As the compound forming the (to) triazine group, a compound represented by the general formula: (Here, R ¹ is the same as above, and R ⁴ is a halogen atom or an acetyl group.) Specifically, 4-chloro-1,3,5-triazine, 4-acetyl- 1,3,5-triazine and the like. Specific examples of the compound that forms (h) (thio) carboxyl group include carbon dioxide, carbon disulfide, maleic anhydride, fumaric anhydride, and itaconic anhydride. (I) Specific examples of the compound forming an amino group include N, N-dimethylaminobenzaldehyde and vinylpyridine. The proportion of the linear diene polymer (B) contained in the diene polymer rubber composition of the present invention is 15% by weight or more, preferably 30 to 80% by weight, and a functional group is less than 15% by weight. The effect of degrading the pain effect due to the addition is small. The hydrogenation rate of the linear diene polymer (B) is less than 30%. However, in the present invention, the hydrogenation rate of the linear diene polymer (B) may be 0%, but the hydrogenation rate of the branched diene polymer (A) is 0%.
When, the hydrogenation rate of the linear diene polymer (B) is 0.
Greater than%. The branched diene polymer (A)
The vinyl bond content of the butadiene portion before hydrogenation is not particularly limited, but is preferably 15 to 60% by weight, particularly preferably 15 to 50% by weight. The vinyl bond content of the butadiene portion of the linear diene polymer (B) before hydrogenation is 20% by weight or more, preferably 20 to 70% by weight,
Particularly preferably, it is from 30 to 60% by weight, and when it is less than 20% by weight, the Mooney viscosity becomes high and the workability deteriorates, while when it exceeds 70% by weight, the exothermic property and breaking strength of the obtained rubber composition are inferior. Become. Further, the Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the branched diene polymer (A) or the linear diene polymer (B) of the present invention is preferably 10 to 150, and is obtained when it is less than 10. On the other hand, the tensile property of the composition is deteriorated, while when it exceeds 150, the workability is deteriorated,
Neither is preferred. The branched diene-based polymer (A) and the linear diene-based polymer (B) of the present invention are obtained by adding an organolithium compound to a diene monomer in an organic solvent together with an aromatic vinyl compound if necessary. Solution polymerization as an initiator, then coupling or introduction of a functional group to obtain an unhydrogenated branched diene polymer (A) and a linear diene polymer (B), and then these polymers It is obtained by hydrogenating at least one of the above in a range of less than 30%. Here, as the diene-based monomer, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, isoprene, chloroprene, 1,3-pentadiene and the like can be used. Of these, 1,3-butadiene is preferable. As the aromatic vinyl compound, styrene, p-methylstyrene, vinyltoluene, α-methylstyrene, pt-butylstyrene and the like are used. Of these, styrene is preferred. In addition,
The amount of the aromatic vinyl compound monomer used is 0 to 60% by weight, preferably 3 to 45% by weight, based on the diene monomer, and if it is used in excess of 60% by weight, the exothermic properties are poor. Will be things. As the organic solvent, pentane,
Hydrocarbon solvents such as hexane, heptane, octane, methylcyclopentane, cyclohexane, benzene and xylene are used. Examples of the organolithium compound as a polymerization initiator include n-butyllithium, sec-butyllithium, t-butyllithium, alkyllithium such as 1,4-dilithiobutane, alkylenedilithium, and the like. Used in an amount of 0.02 to 0.2 part by weight. At this time, a Lewis base such as ether or amine as a regulator of the microstructure, that is, the vinyl bond content of the diene portion, specifically, diethyl ether, tetrahydrofuran, propyl ether, butyl ether, higher ether, or ethylene glycol dibutyl ether. , An ether derivative of polyethylene glycol such as diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, and triethylene glycol dimethyl ether, and examples of amines include tertiary amines such as tetramethylethylenediamine, pyridine, and tributylamine, which are used together with a solvent. Further, the polymerization reaction is usually -30 ° C to +150.
C. is carried out. Particularly, in consideration of the coupling reaction described later, 110 ° C. or lower is preferable. Further, the polymerization may be carried out while controlling at a constant temperature, or may be carried out at an elevated temperature without removing heat. The general method for producing the diene-based polymer used in the present invention is as described above. To produce the branched diene-based polymer (A) and the linear diene-based polymer (B), The following specific formulations are required. First, in order to produce the branched diene polymer (A), an organolithium compound is used as an initiator in a hydrocarbon solvent as described above, for example, JP-B-36-153.
It is obtained by preparing a linear diene polymer having a desired molecular weight by the method disclosed in Japanese Patent Publication No. 86, etc., and then adding a trifunctional or higher polyfunctional coupling agent in a predetermined ratio. The coupling agent reacts with the terminal living polymer produced by anionic polymerization. Therefore, the amount of the coupling agent to which the reaction proceeds quantitatively is approximately 1 / n molar amount with respect to 1 mol of the terminal living polymer in the case of a coupling agent having n coupling-capable groups. 100% coupling is performed. The trifunctional or higher-functional polyfunctional coupling agent in all coupling agents may be used in a molar ratio such that the polymer is limited by the present invention. Therefore, in order to obtain the branched diene-based polymer (A) used in the present invention, for example, when tin tetrachloride or silicon tetrachloride is used as an example of the polyhalide compound as the coupling agent, all four Since it has a group capable of coupling, based on 1 mol of the organolithium compound effectively used as an initiator, either tin tetrachloride or silicon tetrachloride or a total amount of 0.0375 mol or more is used. Alternatively, they may be added separately to carry out the coupling reaction. The branched diene polymer (A)
In order to make the coupling bond between the living polymer and the coupling compound, for example, the bond between the metal and butadiene constituting the coupling compound, that is, the metal-butadienyl bond, a trifunctional or higher functional coupling agent is used. Immediately before causing the coupling reaction, a small amount of diene monomer (organic lithium compound lithium 1
It is obtained by adding 0.5 to 100 mol per g atomic equivalent). Examples of trifunctional or higher polyfunctional coupling agents include polyhalide compounds, for example, tin halide compounds such as tetrachlorotin, trichloromethyltin, tetrabromotin, and bistrichlorostannylethane; silicon, germanium, lead, and boron. Polyhalides such as;
Hexachlorophosphazene, phosphorus pentachloride, phosphorus trichloride, polyepoxides such as epoxidized soybean oil, triglycidylaminophenol, tetraglycidylaminodiphenylmethane; polyisocyanates such as toluene diisocyanate, hexamethylene diisocyanate, methylenediphenyl diisocyanate, isophorone diisocyanate, crude Methylene phenyl isocyanate, aromatic triisocyanate, aromatic tetraisocyanate, aromatic oligoisocyanate; polyhalogenated carbon such as carbon tetrachloride, tetrahalogenated carbon such as tetrachloroethane, trihalogenated carbon such as chloroform and trichlene; polyester, For example, adipic acid diester, terephthalic acid diester, dibutyltin dilaurate, dibutyltin diacetate. Such as the over door is used. Among these coupling agents, tin compounds or polyisocyanates are particularly preferable in order to improve the rolling friction resistance of the obtained rubber composition. Next, in order to produce the linear diene-based polymer (B), an organolithium compound is used as an initiator in a hydrocarbon solvent as described above. For example, as described above, Japanese Patent Publication No. 36-15386. A linear diene-based polymer having a desired molecular weight is prepared by the method shown, and then a compound having a predetermined ratio of the above-mentioned (a) to (i) functional groups (hereinafter, may be simply referred to as "functional group agent"). ) Is added. The functional base is
Reacts with the terminal living polymer produced by anionic polymerization. Therefore, in the case of a functional base having n (1 to 2) functional groups, the addition amount of the functional base in which the reaction proceeds quantitatively is 1 / n mol based on 1 mol of the terminal living polymer. As a result, almost 100% of the functional groups are introduced into the living polymer. The functional base of the present invention in all the functional bases may be used in a molar ratio so as to obtain the polymer limited in the present invention. Therefore, in order to obtain the linear diene-based polymer (B) used in the present invention, for example, when monochlorotrimethyltin or monochlorotrimethylsilicon is used as the functional base, any one of them can be coupled. Since it has a functional group, one or more of monochlorotrimethyltin and monochlorotrimethylsilicon as a total amount of 0.15 mol or more is used per 1 mol of the organolithium compound effectively used as an initiator, simultaneously or separately. In addition, a coupling reaction may be performed. When the linear diene polymer (B) is produced, the living polymer and the functional group are bound to each other, for example, by a metal-butadiene bond constituting the functional group, that is, a metal-butadienyl bond. Is a small amount of 1,3-butadiene (0.5 to 100 mol per 1 g of lithium equivalent of the organolithium compound) immediately before the reaction by using a functional base agent.
Is obtained by adding When a functional group other than a metal is selectively monofunctionally reacted, it can be reacted in the form of a styryl anion. In order to prepare a composition containing the branched diene polymer (A) and the straight chain diene polymer (B) used in the present invention, both prepared separately are mixed. Alternatively, after the polymerization reaction of the diene-based monomer is completed, the coupling agent is first added to the polymerization reaction system to cause a coupling reaction, and then the functional group is added to the reaction system. Thus, a mixture of the branched diene polymer (A) and the linear diene polymer (B) may be prepared. When the branched diene-based polymer (A) or linear diene-based polymer (B) of the present invention is hydrogenated, each of the unhydrogenated polymers thus obtained is usually dicyclopentadiene. Dienyl titanium halide, organic nickel carboxylate, hydrogenation catalyst consisting of organic nickel nickel carboxylate and an organometallic compound of Group I-III of the periodic table, nickel supported on carbon, silica, diatomaceous earth, platinum, palladium, ruthenium,
With a rhenium or rhodium metal catalyst or cobalt, nickel, rhodium or ruthenium complex as a catalyst, 1 to 100
Under hydrogen pressurized to atmospheric pressure, or in the presence of lithium aluminum hydride, p-toluenesulfonyl hydrazide, or Zr-Ti-Fe-V-Cr alloy, Z
It can be obtained by hydrogenation in the presence of a hydrogen storage alloy such as r-Ti-Nb-Fe-V-Cr alloy or LaNi ₅ alloy, or under hydrogen pressurized to 1 to 100 atm. These polymers are hydrocarbon solvents such as hexane, heptane, cyclohexane, benzene, toluene, ethylbenzene, or methyl ethyl ketone, ethyl acetate,
It is hydrogenated by the above-mentioned hydrogenation catalyst or hydrogenation compound in a polar solvent such as ethyl ether or tetrahydrofuran. The thus obtained solution of the branched hydrogenated diene polymer (A) or the linear hydrogenated diene polymer (B) having a hydrogenation rate of less than 30% was removed by steam stripping. A solid polymer (composition) is obtained by coagulating with a solvent or alcohol and then drying. The diene polymer rubber composition of the present invention can be used as a rubber composition by blending other diene rubbers such as natural rubber, polyisoprene rubber, polybutadiene rubber, emulsion-polymerized styrene-butadiene rubber. . In this case, the content of each of the diene polymers (A) and (B) of the present invention is required to be 15% by weight or more in order to achieve the above-mentioned effects of the present invention. In addition, if necessary, extend the oil, add the usual compounding agent for vulcanized rubber, vulcanize it, tires, anti-vibration rubber,
Used for belts, hoses and other industrial products.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited to the examples as long as the gist of the present invention is not exceeded. In the examples, parts and% are by weight unless otherwise specified. Various measurements in the examples were based on the following methods. That is, the content of the functional base is determined by the Fourier Transform NMR spectrometer [Fourier Transform NMR].
Spectrometer (FT-NMR)] for a predetermined time, or by atomic absorption analysis. The number of branches of the branched polymer was calculated from the molecular weight of each peak top of gel permeation chromatography (GPC). The vinyl bond content was determined by an infrared method (Morello method). The bound styrene content was determined from an infrared calibration curve based on the absorption of a phenyl group at 699 cm ^-1 . Mooney viscosity (M
L _{1 + 4} , 100 ° C.) was measured according to JIS K6300. The workability was evaluated by visual inspection of the dump rubber after kneading and its glossiness. ◎ indicates that the dump rubber is gathering and the gloss is extremely excellent (excellent), and 〇 indicates that the dump rubber is gathering and the gloss is good. (Good) and Δ indicate that the dump rubber is collected and the gloss is slightly inferior (OK). Tensile strength (tensile properties) is JIS K
6301, ◎ indicates a tensile strength of 270 kgf /
cm ² or more, ◯ has a tensile strength of 220 kgf / cm ² or more and less than 270 kgf / cm ² , and Δ has a tensile strength of 220 kg
It is less than f / cm ² . For the Payne effect, RMS
Manufactured, the difference (Δ tan δ) between the maximum value and the minimum value of tan δ of the strain dispersion curve of tan δ at 50 ° C. measured by a mechanical spectrometer, and in the case of Δ tan δ,
◎ is less than 0.04, ◯ is 0.04 or more and less than 0.07, △
Is 0.07 or more. Further, tan δ (0 ° C.) and tan δ (30 ° C.) were obtained from the temperature dispersion curve of tan δ at 15 Hz and 1% strain. The Lambourn abrasion index, which is a wear resistance test, was measured by the Lambourn abrasion method. The measurement conditions are a load of 4.5 kg and a grindstone surface speed of 1.
00 m / sec, the test piece speed was 130 m / sec, the slip ratio was 30%, the amount of falling sand was 20 g / min, and the measurement temperature was room temperature. This Lambourn abrasion index has a vinyl bond content of 25.
%, The styrene-butadiene copolymer having a styrene content of 25% was defined as 100. The larger the value, the better the wear characteristics. Here, ◎ is 140 or more, ◯ is 110
It is less than 140 and less than 110.

【Example】

Examples 1-5 and Comparative Examples 1-2 After charging cyclohexane, a monomer, and tetrahydrofuran according to the prescription shown in Table 1 to a reactor having an internal volume of 5 l, 20 were prepared by using the polymerization initiator shown in Table 1. Polymerization was carried out at ˜90 ° C. for 1.5 hours. Then, the type and amount of coupling agent or functional group shown in Table 1 is added,
Coupling reaction or functional group introduction reaction at 60 ° C, 3
It went for 0 minutes. 2,6-di-t-butyl-in the polymer solution
After adding 3.5 g of p-cresol, the solvent was removed by steam stripping and further dried at 110 ° C. on a hot roll to obtain a polymer. The properties of the obtained polymer are also shown in Table 1. Next, various polymers having different bound styrene contents, vinyl bond contents in the butadiene part, coupling agents or functional bases obtained above were charged into an autoclave having an internal volume of 5 l to prepare a 10% toluene solution. After substituting the system with nitrogen, p-toluenesulfonyl hydrazide was charged so as to be 2 mol per 1 mol of the polymer. After that, hydrogen was introduced into the reaction system at 110 ° C.
Was reacted. After the desired amount of hydrogenation, the polymer solution was withdrawn and dissolved in 5 ml of alcohol, 2,6-tert-
Butyl-p-cresol was added to stop the reaction, and the solvent was removed by a conventional method, followed by drying with a roll at 110 ° C. to obtain a hydrogenated diene polymer. This polymer was then used to prepare 230 cc Brabender and 6 according to the formulation shown below.
After kneading and blending with an inch roll, various measurements were performed using a vulcanized product that was vulcanized at 160 ° C. for a predetermined time. Table 2 shows the results. Formulation (part) Polymer 100 Carbon black (HAF) 50 Zinc white 3 Stearic acid 1 Anti-aging agent (810NA) * 1) 1 Vulcanization accelerator (DPG) * 2) 0.8 Vulcanization accelerator (DM) * 3) 0.6 Sulfur 1.5 * 1) N-phenyl-N'-isopropyl-p-phenylenediamine * 2) Diphenylguanidine * 3) Benzothiazyl disulfide From Tables 1 and 2, direct comparison with Comparative Example 1 When the chain diene-based polymer (B) is used alone, the processability, tensile strength, and wear resistance deteriorate, and from Comparative Example 2, the linear diene-based polymer (B) has a specific functional group. It can be seen that when the polymer is not added, blending the polymer with the branched diene polymer (A) undesirably increases the Payne effect.

INDUSTRIAL APPLICABILITY The present invention comprises a branched diene polymer having excellent breaking strength and a linear diene polymer having a specific functional group which improves carbon dispersibility, and has low heat buildup. It is possible to provide a diene-based polymer having excellent breaking strength, abrasion resistance, workability, and pain effect.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Fumio Tsutsumi 2-11 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (72) Inventor Hideki Komatsu 3-5-5 Ogawa Higashicho, Kodaira-shi, Tokyo (72) Inventor Tatsuo Fujimaki 3-2-3 Fujimi-cho, Higashimurayama-shi, Tokyo

Claims (2)

[Claims] 1. A rubber component comprising at least 15% by weight of a branched diene polymer (A) and at least one functional group selected from the groups (a) to (i) below in the molecular chain. At least 15% by weight of a linear diene-based polymer (B) having a vinyl bond content of 20% by weight or more, and a branched diene-based polymer (A) and a linear diene-based polymer A hydrogenation rate of each of the polymers (B) is less than 30%, and a diene polymer rubber composition. (B) R 1 ³ _M group (wherein, R ¹ is an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group or an ester group, M is silicon atom, a germanium atom or a tin atom.) ( b) (thio) carbonyl group ^(c) _{R 2} 2 P- group (wherein, ^{R 2} is an alkyl group, an aryl group, an aralkyl group, an alkoxy group or an ester group.) (d) (Here, Y is an oxygen atom or a sulfur atom, and R ² is the same as above.) (E) Amido group (f) Imino group (to) Triazine group (thi) (thio) Carboxyl group (ri) Amino group 2. The diene polymer according to claim 1, wherein the branched diene polymer (A) and the linear diene polymer (B) are polymerized with an organolithium compound as an initiator. Rubber composition.