JP6375174B2 - Modified farnesene polymer, method for producing the same, rubber composition, and tire - Google Patents

Description

  The present invention relates to a modified farnesene polymer containing monomer units derived from farnesene, a process for producing the same, a rubber composition containing the modified farnesene polymer, and a tire using the rubber composition.

Conventionally, rubber compositions that have improved mechanical strength by blending fillers such as carbon black and silica with rubber components such as natural rubber and styrene butadiene rubber are used for tires that require wear resistance and mechanical strength. Widely used.
It is known that the filler exerts its reinforcing effect by physically or chemically adsorbing the rubber component on the particle surface. Therefore, when a filler having a large particle size of about 100 to 200 nm is used, the interaction with the rubber component is generally not sufficiently obtained, and therefore the mechanical strength of the rubber composition cannot be sufficiently improved. There was a case. Further, when the rubber composition is used as a tire, the hardness is lowered and the steering stability may be insufficient.

On the other hand, when a filler having a small average particle diameter of about 5 to 100 nm and a large specific surface area is used, since the interaction between the filler and the rubber component increases, characteristics such as mechanical strength and wear resistance of the rubber composition Will improve. Moreover, since the hardness becomes high when the rubber composition is used as a tire, steering stability is improved.
However, it is known that when a filler having a small average particle diameter is used, the dispersibility of the filler in the rubber composition is lowered due to the high cohesive force between carbon black or silica. This decrease in the dispersibility of the filler may lead to a longer kneading process and may affect the productivity of the rubber composition. Moreover, since the rubber composition easily generates heat when the dispersibility is lowered, the rolling resistance performance is deteriorated, and the required characteristics of so-called low fuel consumption tires are often not satisfied. Further, even when the kneading time is increased and the dispersion of the filler is improved, the network structure by the filler in the rubber composition is reduced, so that the elastic modulus as the rubber composition may be lowered.
Thus, the mechanical strength and hardness of the tire rubber composition and the rolling resistance performance are in a trade-off relationship, and it is difficult to improve both in a well-balanced manner.

As a rubber composition for improving the above properties in a well-balanced manner, Patent Document 1 specifies a rubber component containing isoprene-based rubber and styrene-butadiene rubber, carbon black, and a liquid resin having a softening point of -20 to 20 ° C. The rubber composition for tires contained in the ratio is described.
Patent Document 2 discloses a tire in which a rubber component containing a diene rubber containing a modified styrene-butadiene copolymer and a modified conjugated diene polymer and a filler such as carbon black are blended at a predetermined ratio. Have been described.
Although Patent Documents 3 and 4 describe polymers of β-farnesene, practical applications have not been sufficiently studied.

JP 2011-195804 A JP 2010-209256 A International Publication No. 2010/027463 International Publication No. 2010/027464

According to the tires described in Patent Documents 1 and 2, although the above-mentioned problems can be solved to some extent, the mechanical strength, hardness, and handling stability resulting from hardness and rolling resistance performance are combined at a sufficiently high level. However, further improvement is desired.
This invention is made | formed in view of the said situation, and suppresses the heat_generation | fever accompanying friction between fillers by interacting with fillers, such as carbon black and a silica, when it uses for a part of rubber composition. A modified farnesene polymer capable of improving the elastic modulus and a method for producing the same are provided.
A rubber composition containing the modified farnesene polymer, wherein the crosslinked product (including vulcanized rubber; the same applies hereinafter) exhibits excellent hardness, mechanical strength, elastic modulus, and wear resistance. provide.
Further, the present invention provides a tire having at least a part of the rubber composition and having excellent handling stability and excellent rolling resistance performance due to high hardness.

  As a result of intensive studies, the present inventors have found that when a modified farnesene polymer containing a farnesene-derived monomer unit and having a specific amount of a specific structure is used in a rubber composition, a crosslinked product of the rubber composition is used. Was found to exhibit excellent performance in terms of hardness, mechanical strength, elastic modulus and abrasion resistance, and completed the present invention.

That is, the present invention relates to the following [1] to [4].
[1] A modified farnesene polymer having one or more functional groups selected from a dicarboxylic acid structure (a1), a dicarboxylic acid monoester structure (a2), a dicarboxylic acid monoamide structure (a3), and a carboxylic anhydride structure (a4). And the modified farnesene polymer whose whole quantity of said (a1)-(a3) is 80 mol% or more with respect to the whole quantity of said (a1)-(a4).
[2] The method for producing a modified farnesene polymer according to [1], wherein the carboxylic anhydride portion of the farnesene polymer modified with carboxylic anhydride is subjected to a ring-opening reaction.
[3] A rubber composition containing 20 to 150 parts by mass of filler (B) with respect to 100 parts by mass of one or more rubber components (A) selected from synthetic rubber and natural rubber. A rubber composition containing 0.1 to 30 parts by mass of the modified farnesene polymer (C) according to [1] with respect to parts by mass.
[4] A tire using at least a part of the rubber composition according to [3].

According to the present invention, when used as a part of a rubber composition, it interacts with fillers such as carbon black and silica, thereby suppressing heat generation due to friction between fillers and improving elastic modulus. It is possible to provide a modified farnesene polymer that can be produced, and a method for producing the same.
Moreover, it is possible to provide a rubber composition containing the modified farnesene polymer, in which the crosslinked product exhibits excellent hardness, mechanical strength, elastic modulus, and wear resistance.
Furthermore, it is possible to provide a tire having excellent steering stability and excellent rolling resistance performance due to high hardness by using the rubber composition at least in part.

[Modified farnesene polymer]
The modified farnesene polymer of the present invention has one or more functional groups selected from a dicarboxylic acid structure (a1), a dicarboxylic acid monoester structure (a2), a dicarboxylic acid monoamide structure (a3), and a carboxylic anhydride structure (a4). A modified farnesene polymer having a total amount of (a1) to (a3) of 80 mol% or more based on the total amount of (a1) to (a4).

  As the farnesene constituting the modified farnesene polymer in the present invention, at least one selected from α-farnesene and β-farnesene represented by the formula (I) can be used. From the viewpoint of ease of production, β-farnesene Is preferably used.

As the dicarboxylic acid structure (a1), a structure derived from an unsaturated dicarboxylic acid is preferable, and specifically, a structure derived from maleic acid, fumaric acid, citraconic acid, itaconic acid, 2,3-dimethylmaleic acid, or the like. Can be mentioned.
As the dicarboxylic acid monoester structure (a2), a structure derived from an unsaturated dicarboxylic acid monoester is preferable, and dicarboxylic acid monomethyl ester, dicarboxylic acid monoethyl ester, dicarboxylic acid monopropyl ester, or dicarboxylic acid monobutyl ester is preferable. Specific examples include structures derived from maleic acid monoester, fumaric acid monoester, citraconic acid monoester, itaconic acid monoester, 2,3-dimethylmaleic acid monoester, and the like.

  The dicarboxylic acid monoamide structure (a3) is preferably a structure derived from an unsaturated dicarboxylic acid monoamide, specifically, maleic acid monoamide, fumaric acid monoamide, citraconic acid monoamide, itaconic acid monoamide, and 2,3-dimethylmaleic acid. Examples include structures derived from monoamides and the like.

  As the carboxylic anhydride structure (a4), a structure derived from an unsaturated carboxylic anhydride is preferable, and specifically, derived from maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, itaconic anhydride, or the like. The structure to do is mentioned.

  Among these, from the viewpoint of improving the interaction with fillers such as carbon black and silica when the modified farnesene polymer of the present invention is used in a part of the rubber composition, maleic acid is preferable as the dicarboxylic acid, The dicarboxylic acid monoester is preferably a maleic acid monoester, and the dicarboxylic acid monoamide is preferably a maleic acid monoamide. Moreover, as said dicarboxylic acid monoester, dicarboxylic acid monomethyl ester, dicarboxylic acid monoethyl ester, dicarboxylic acid monopropyl ester, and dicarboxylic acid monobutyl ester are preferable.

In the modified farnesene polymer of the present invention, the total amount of (a1) to (a3) is required to be 80 mol% or more based on the total amount of (a1) to (a4). When the amount of (a1) to (a3) in the total amount of (a1) to (a4) is 80 mol% or more, when the modified farnesene polymer of the present invention is used as a part of the rubber composition, Interaction with fillers such as carbon black and silica is enhanced, and the elastic modulus and rolling resistance performance are improved.
From the viewpoint of improving the interaction between the modified farnesene polymer and the filler, the amount of (a1) to (a3) in the total amount of (a1) to (a4) is preferably 85 mol% or more, and 90 mol% or more. More preferably, it is more preferably 95 mol% or more, and may be 100 mol%. The total amount of each functional group and the amount of each functional group in the modified farnesene polymer can be calculated using an analytical instrument such as infrared spectroscopy or nuclear magnetic resonance spectroscopy.

The total amount of (a1) to (a4) in the modified farnesene polymer is preferably 0.1 to 50% by mass. A filler such as carbon black or silica when the modified farnesene polymer of the present invention is used as part of a rubber composition when the total amount of (a1) to (a4) in the modified farnesene polymer is within the above range. And the elastic modulus and rolling resistance performance are improved. Moreover, since it can prevent that a viscosity becomes high as the whole quantity of said (a1)-(a4) in a modified | denatured farnesene polymer is 50 mass% or less, manufacture becomes easy.
The total amount of the above (a1) to (a4) in the modified farnesene polymer is preferably 0.1 to 50% by mass, and preferably 0.2 to 45% by mass from the viewpoint of improving the interaction between the modified farnesene polymer and the filler. % Is more preferable, and 0.5 to 40% by mass is still more preferable. The total amount of each functional group in the modified farnesene polymer can be calculated using an analytical instrument such as infrared spectroscopy or nuclear magnetic resonance spectroscopy. The modified farnesene polymer may contain a functional group other than the above (a1) to (a4) within a range not impairing the effects of the invention.

The weight average molecular weight (Mw) of the modified farnesene polymer is preferably 2000 to 500,000, more preferably 150,000 to 500,000, still more preferably 20,000 to 450,000, and still more preferably 30,000 to 300,000. When the Mw of the modified farnesene polymer is within the above range, the processability of the rubber composition of the present invention becomes good, and the rolling resistance performance of a tire using a crosslinked product of the rubber composition becomes good.
In the present specification, Mw of the modified farnesene polymer is a value determined by the method described in the examples described later. In the present invention, two types of modified farnesene polymers having different Mw may be used in combination.

  The melt viscosity at 38 ° C. of the modified farnesene polymer is preferably 0.1 to 3,000 Pa · s, more preferably 1.0 to 2,000 Pa · s, still more preferably 2.5 to 1,500 Pa · s, 4.0 to 1,000 Pa · s is even more preferable. When the melt viscosity of the modified farnesene polymer is within the above range, kneading of the resulting rubber composition is facilitated and processability is improved. In the present specification, the melt viscosity of the modified farnesene polymer is a value determined by the method described in the examples described later.

  The molecular weight distribution (Mw / Mn) of the modified farnesene polymer is preferably 1.0 to 8.0, more preferably 1.0 to 5.0, and still more preferably 1.0 to 3.0. It is more preferable that Mw / Mn is within the above-mentioned range because the variation of the viscosity of the resulting modified farnesene polymer is small.

  The glass transition temperature of the modified farnesene polymer is preferably in the range of -90 to 10 ° C, more preferably in the range of -90 to 0 ° C, and still more preferably in the range of -90 to -5 ° C. Within the above range, the rolling resistance performance of the tire using the crosslinked product of the rubber composition containing the modified farnesene polymer of the present invention is improved. Moreover, it can suppress that a viscosity becomes high and can handle it easily.

(Method for producing modified farnesene polymer)
The modified farnesene polymer may be, for example, an unmodified farnesene polymer, and a dicarboxylic acid structure (a1), a dicarboxylic acid monoester structure (a2), a dicarboxylic acid monoamide structure with respect to the unmodified farnesene polymer. It can be produced by introducing one or more functional groups selected from (a3) and the carboxylic anhydride structure (a4).

[Method for producing unmodified farnesene polymer]
The unmodified farnesene polymer can be produced by an emulsion polymerization method, a method described in International Publication No. 2010/027463, International Publication No. 2010/027464, or the like. Among these, an emulsion polymerization method or a solution polymerization method is preferable, and a solution polymerization method is more preferable.

As an emulsion polymerization method for obtaining an unmodified farnesene polymer, a known method can be applied. For example, a predetermined amount of farnesene monomer is emulsified and dispersed in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator.
As the emulsifier, for example, a long chain fatty acid salt or rosin acid salt having 10 or more carbon atoms is used. Specific examples include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid and stearic acid.
As a dispersion medium, water is usually used, and a water-soluble organic solvent such as methanol and ethanol may be contained as long as stability during polymerization is not hindered.
Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides, and hydrogen peroxide.
In order to adjust the molecular weight of the resulting unmodified farnesene polymer, a chain transfer agent can also be used. Examples of the chain transfer agent include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan; carbon tetrachloride, thioglycolic acid, diterpene, terpinolene, γ-terpinene, α-methylstyrene dimer, and the like.
The emulsion polymerization temperature can be appropriately selected depending on the type of radical polymerization initiator to be used, but is usually preferably in the range of 0 to 100 ° C, more preferably in the range of 0 to 80 ° C. The polymerization mode may be either continuous polymerization or batch polymerization. The polymerization reaction can be stopped by adding a polymerization terminator.

Examples of the polymerization terminator include amine compounds such as isopropylhydroxylamine, diethylhydroxylamine, and hydroxylamine, quinone compounds such as hydroquinone and benzoquinone, and sodium nitrite.
After termination of the polymerization reaction, an antioxidant may be added as necessary. After the polymerization reaction is stopped, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride, potassium chloride is used as a coagulant, and nitric acid, sulfuric acid, etc. The unmodified farnesene polymer is coagulated while adjusting the pH of the coagulation system to a predetermined value by adding acid, and then the unmodified farnesene polymer is recovered by separating the dispersion solvent. Subsequently, after washing with water and dehydration, drying is performed to obtain an unmodified farnesene polymer. Note that, during the coagulation, if necessary, latex and an extending oil that has been made into an emulsified dispersion may be mixed and recovered as an oil-extended unmodified farnesene polymer.

As a solution polymerization method for obtaining an unmodified farnesene polymer, a known method can be applied. For example, a farnesene monomer is polymerized in a solvent using a Ziegler catalyst, a metallocene catalyst, and an anion-polymerizable active metal, if desired, in the presence of a polar compound.
Examples of the anion-polymerizable active metal include alkali metals such as lithium, sodium and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; lanthanoid rare earth metals such as lanthanum and neodymium . Of these, alkali metals and alkaline earth metals are preferable, and alkali metals are more preferable. When an alkali metal is used, it is preferably used as an organic alkali metal compound.

Examples of the organic alkali metal compound include organic monolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, stilbenelithium; dilithiomethane, dilithionaphthalene Polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is more preferable. The amount of the organic alkali metal compound used is appropriately determined according to the required molecular weight of the farnesene polymer, but is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of farnesene.
The organic alkali metal compound can also be used as an organic alkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine, dibenzylamine and the like.

  Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene, Aromatic hydrocarbons such as toluene and xylene are exemplified.

The polar compound is used to adjust the microstructure of the farnesene moiety in anionic polymerization without deactivating the reaction. For example, ether compounds such as dibutyl ether, tetrahydrofuran, ethylene glycol diethyl ether; tetramethylethylenediamine, trimethylamine, etc. Tertiary amines; alkali metal alkoxides, phosphine compounds and the like. The polar compound is preferably used in an amount of 0.01 to 1000 molar equivalents relative to the organic alkali metal compound.
The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 10 to 90 ° C. The polymerization mode may be either batch or continuous.

The unmodified farnesene polymer may be composed only of the monomer unit (c1) derived from farnesene, and the monomer unit derived from farnesene (c1) and a monomer derived from a monomer other than farnesene. It may be composed of body units (c2).
When the modified farnesene polymer is a copolymer, examples of the monomer unit (c2) derived from monomers other than farnesene include conjugated dienes having 12 or less carbon atoms and aromatic vinyl compounds. .
Examples of the conjugated diene having 12 or less carbon atoms include butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, Examples include 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, chloroprene and the like. Of these, butadiene, isoprene, and myrcene are more preferable. These conjugated dienes may be used alone or in combination of two or more.

  Examples of the aromatic vinyl compound include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4- Dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, 1-vinylnaphthalene, 2- Aromatic vinyl compounds such as vinylnaphthalene, vinylanthracene, N, N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, divinylbenzene, and the like can be given. Among these, styrene, α-methylstyrene, and 4-methylstyrene are preferable.

In the copolymer, the ratio of the monomer unit (c2) to the total of the monomer unit (c1) derived from farnesene and the monomer unit (c2) derived from a monomer other than farnesene is obtained as a rubber composition. From the viewpoint of improving the workability of the product and the rolling resistance performance, 1 to 99 mass% is preferable, 10 to 80 mass% is more preferable, and 15 to 80 mass% is still more preferable.
Moreover, 40-80 mass% is preferable from a viewpoint of improving abrasion resistance, and 60-80 mass% is more preferable. From a viewpoint of improving workability, 20 to 60% by mass is preferable, and 20 to 40% by mass is more preferable.
Further, the monomer unit (c2) derived from a monomer other than farnesene is more preferably butadiene from the viewpoint of improving rolling resistance performance and wear resistance.

[Modification method of unmodified farnesene polymer]
The modified farnesene polymer is obtained by a modification method such as a method of adding a polymerization terminator to the unmodified farnesene polymer and then grafting a modifying agent such as maleic anhydride onto the unmodified farnesene polymer. be able to.
As said modifier, it is 1 or more types chosen from dicarboxylic acid, dicarboxylic acid monoester, dicarboxylic acid monoamide, and carboxylic anhydride, Comprising: The compound corresponding to said (a1)-(a4) can be used. . That is, the modified farnesene polymer of the present invention can be produced by grafting the compounds corresponding to the above (a1) to (a4) to an unmodified farnesene polymer.

Examples of the modifying agent that can be used in the above method include unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, itaconic acid, and 2,3-dimethylmaleic acid; maleic acid monoester, fumaric acid monoester, and citracone. Unsaturated monocarboxylic acid monoesters such as acid monoester, itaconic acid monoester, 2,3-dimethylmaleic acid monoester; maleic acid monoamide, fumaric acid monoamide, citraconic acid monoamide, itaconic acid monoamide, 2,3-dimethylmaleic acid Unsaturated dicarboxylic acid monoamides such as monoamides; unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, itaconic anhydride, and the like.
The usage-amount of the said modifier with respect to 100 mass parts of unmodified farnesene polymers becomes like this. Preferably it is 0.1-100 mass parts, More preferably, it is 0.5-50 mass parts. The reaction temperature is preferably in the range of 0 to 200 ° C.

The modified farnesene polymer of the present invention is converted to any functional group selected from the above (a1) to (a3) by ring-opening reaction of the carboxylic anhydride portion of the farnesene polymer modified with carboxylic anhydride. Can also be manufactured.
The ring-opening reaction for ring-opening the carboxylic anhydride can be performed by reacting the carboxylic anhydride-modified farnesene polymer with one or more ring-opening reagents selected from water, alcohol, ammonia, and amine. Among the ring-opening reagents, alcohols having 1 to 20 carbon atoms and amines having 1 to 20 carbon atoms are preferable from the viewpoint of ease of production. Examples of the alcohol include methanol, ethanol, propanol, butyl alcohol, isopropyl alcohol, ethylene glycol, propylene glycol, and isoprene glycol. Examples of the amine include methylamine, ethylamine, propylamine, aniline, hydroxylamine and the like. Among these, C1-C20 alcohol is preferable and methanol is more preferable. For example, when methanol is used as a ring-opening reagent for a maleic anhydride-modified farnesene polymer, a modified farnesene polymer having a maleic acid monomethyl ester group and a maleic anhydride group can be obtained.

In the ring-opening reaction, the amount of the ring-opening reagent is preferably 0.5 to 5 equivalents, more preferably 0.8 to 5 equivalents, relative to the carboxylic anhydride.
The reaction temperature of the ring-opening reaction is preferably from 0 to 100 ° C, more preferably from 25 to 100 ° C, from the viewpoint of promptly proceeding the reaction.

  In the present invention, a modifier is grafted to an unmodified farnesene polymer, and after introducing each structure, a compound capable of reacting with each structure is further added to introduce another functional group into the polymer. May be. Specifically, a method in which maleic anhydride is grafted to an unmodified farnesene polymer obtained by living anion polymerization, and then reacted with 2-hydroxyethyl methacrylate, 2-hydroxyethyl vinyl ether, or the like. .

In the present invention, during the reaction for introducing a functional group into the unmodified farnesene polymer, and during storage of the modified farnesene polymer, the unmodified farnesene is used for the purpose of suppressing a decrease in molecular weight, discoloration, and gelation due to deterioration. You may mix | blend suitable anti-aging agent with a polymer or a modified | denatured farnesene polymer. Specifically, 4,4′-butylidenebis (3-methyl-6-tert-butylphenol) (AO-40), 3,9-bis [1,1-dimethyl-2- [3- (3-t- Butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane (AO-80), bis (2,2,6,6- Tetramethyl-4-piperidyl) sebacate (LA-77Y) (above, manufactured by ADEKA), 2,4-bis [(octylthio) methyl] -6-methylphenol (Irganox 1520L), 2,4-bis [(dodecylthio) Methyl] -6-methylphenol (Irganox 1726), bis (4-t-octylphenyl) amine (Irganox 5057), tris phosphite (2,4-di-t-butylpheny ) (Irgafos 168), N, N-dioctadecylhydroxylamine (Irgastab FS 042) (all of which are manufactured by BASF), 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate (Sumilizer GS), 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (Sumilizer GM) , 6-t-butyl-4- [3- (2,4,8,10-tetra-t-butyldibenzo [d, f] [1,3,2] dioxaphosphin-6-yloxy) propyl] -2-methylphenol (Sumilizer GP) (all of which are manufactured by Sumitomo Chemical Co., Ltd.), p-methoxyphenol, N-phenyl-N ′-(1,3 Dimethylbutyl) -p-phenylenediamine (NOCRACK 6C) (manufactured by Ouchi Shinsei Chemical), 2,6-di-t-butyl-4-methylphenol (BHT), 2,2′-methylenebis (4-methyl-6 t-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), dioctadecyl 3,3′-dithiobispropionate, hydroquinone and the like. Moreover, the said anti-aging agent may use together 1 type (s) or 2 or more types.
The addition amount of the antioxidant is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the unmodified farnesene polymer or modified farnesene polymer.

[Rubber composition]
The rubber composition of the present invention is a rubber composition containing 20 to 150 parts by mass of filler (B) with respect to 100 parts by mass of one or more rubber components (A) selected from synthetic rubber and natural rubber, The rubber composition contains 0.1 to 30 parts by mass of the modified farnesene polymer (C) of the present invention with respect to 100 parts by mass of the filler (B).
In the rubber composition of the present invention, the mechanical strength and wear resistance of the crosslinked product of the rubber composition are improved by using the rubber component (A), the filler (B) and the modified farnesene polymer (C) in combination. Moreover, the rolling resistance performance and steering stability of the tire using the crosslinked product can be improved. Further, the processability at the time of compounding, molding or vulcanization of the rubber composition is good.

From the viewpoint of improving processability, elastic modulus, and rolling resistance performance of the rubber composition, the content of the modified farnesene polymer (C) in the rubber composition of the present invention is 100 parts by mass of the filler (B). And 0.1 to 30 parts by weight, preferably 0.1 to 25 parts by weight, more preferably 1 to 20 parts by weight, and still more preferably 2 to 15 parts by weight.
The modified farnesene polymer (C) used in the rubber composition of the present invention may be a mixture of two or more kinds of modified farnesene polymers having different monomer units, molecular weights and functional groups.

<Rubber component (A)>
As the rubber component (A), one or more rubbers selected from synthetic rubber and natural rubber are used. Examples include rubbers such as styrene butadiene rubber (hereinafter also referred to as “SBR”), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber, and natural rubber. it can. Among these, SBR, butadiene rubber, isoprene rubber, and natural rubber are more preferable, and SBR and natural rubber are more preferable. These rubbers may be used alone or in combination of two or more.

[Synthetic rubber]
When synthetic rubber is used as the rubber component (A) in the present invention, styrene butadiene rubber (hereinafter also referred to as “SBR”), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer Combined rubber, chloroprene rubber, and the like are preferable. Among them, SBR, butadiene rubber, and isoprene rubber are more preferable, and SBR is more preferable.

(SBR (AI))
As the SBR, a general one used for a tire can be used. Specifically, the styrene content is preferably 0.1 to 70% by mass, more preferably 5 to 50% by mass, and 15 More preferred is ~ 35% by mass. Moreover, the thing whose vinyl content is 0.1-60 mass% is preferable, and a 0.1-55 mass% thing is more preferable.
The weight average molecular weight (Mw) of SBR is preferably 100,000 to 2,500,000, more preferably 150,000 to 2,000,000, and even more preferably 200,000 to 1,500,000. When it is in the above range, both workability and mechanical strength can be achieved.
In addition, Mw in this specification is the value measured by the method as described in the below-mentioned Example.
The glass transition temperature (Tg) obtained by differential thermal analysis of SBR used in the present invention is preferably in the range of −95 to 0 ° C., more preferably in the range of −95 to −5 ° C. . By setting Tg within the above range, it is possible to suppress an increase in viscosity and to facilitate handling.

≪SBR manufacturing method≫
The SBR that can be used in the present invention is obtained by copolymerizing styrene and butadiene. There is no restriction | limiting in particular about the manufacturing method of SBR, and any of an emulsion polymerization method, a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method can be used, and an emulsion polymerization method and a solution polymerization method are especially preferable.

(I) Emulsion polymerization styrene butadiene rubber (E-SBR)
E-SBR can be produced by an ordinary emulsion polymerization method. For example, a predetermined amount of styrene and butadiene monomers are emulsified and dispersed in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator.
As the emulsifier, for example, a long chain fatty acid salt or rosin acid salt having 10 or more carbon atoms is used. Specific examples include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid and stearic acid.
As a dispersion medium, water is usually used, and a water-soluble organic solvent such as methanol and ethanol may be contained as long as stability during polymerization is not hindered.
Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides, hydrogen peroxide, and the like.
In order to adjust the molecular weight of the obtained E-SBR, a chain transfer agent can also be used. Examples of the chain transfer agent include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan; carbon tetrachloride, thioglycolic acid, diterpene, terpinolene, γ-terpinene, α-methylstyrene dimer, and the like.

Although the temperature of emulsion polymerization can be suitably selected according to the kind of radical polymerization initiator to be used, the range of 0-100 degreeC is preferable normally and the range of 0-80 degreeC is more preferable. The polymerization mode may be either continuous polymerization or batch polymerization. The polymerization reaction can be stopped by adding a polymerization terminator.
Examples of the polymerization terminator include amine compounds such as isopropylhydroxylamine, diethylhydroxylamine, and hydroxylamine; quinone compounds such as hydroquinone and benzoquinone, and sodium nitrite.
After termination of the polymerization reaction, an antioxidant may be added as necessary. After the polymerization reaction is stopped, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride, potassium chloride is used as a coagulant, and nitric acid, sulfuric acid, etc. The polymer can be recovered as crumbs by adding the acid and coagulating the polymer while adjusting the pH of the coagulation system to a predetermined value and then separating the dispersion solvent. E-SBR can be obtained by washing the crumb with water, followed by dehydration and drying with a band dryer or the like. In addition, at the time of coagulation, if necessary, a latex and an extending oil that has been made into an emulsified dispersion may be mixed and recovered as an oil-extended rubber.
Examples of commercially available E-SBR include oil-extended styrene butadiene rubber “JSR1723” manufactured by JSR Corporation.

(Ii) Solution-polymerized styrene butadiene rubber (S-SBR)
S-SBR can be produced by an ordinary solution polymerization method. For example, an active metal capable of anion polymerization in a solvent is used, and styrene and butadiene are polymerized in the presence of a polar compound as desired.
Examples of the anion-polymerizable active metal include alkali metals such as lithium, sodium and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; lanthanoid rare earth metals such as lanthanum and neodymium . Of these, alkali metals and alkaline earth metals are preferable, and alkali metals are more preferable. Further, among alkali metals, organic alkali metal compounds are more preferably used.
Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene, And aromatic hydrocarbons such as toluene. These solvents are preferably used in a range where the monomer concentration is 1 to 50% by mass.

Examples of the organic alkali metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1,4 -Polyfunctional organic lithium compounds such as dilithio-2-ethylcyclohexane and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is more preferable. The amount of the organic alkali metal compound used is appropriately determined depending on the required molecular weight of S-SBR.
The organic alkali metal compound can also be used as an organic alkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine, and dibenzylamine.
The polar compound is not particularly limited as long as it is usually used for adjusting the microstructure of the butadiene site and the distribution in the copolymer chain of styrene without deactivating the reaction in anionic polymerization. Examples include ether compounds such as dibutyl ether, tetrahydrofuran and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides and phosphine compounds.

The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 30 to 90 ° C. The polymerization mode may be either a batch type or a continuous type. In order to improve the random copolymerization of styrene and butadiene, styrene and butadiene are continuously or intermittently supplied into the reaction solution so that the composition ratio of styrene and butadiene in the polymerization system falls within a specific range. Is preferred.
The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator. Coupling of tin tetrachloride, tetrachlorosilane, tetramethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, etc. that can react with the polymerization active terminal before adding the polymerization terminator An agent, or a polymerization terminal modifier such as 4,4′-bis (diethylamino) benzophenone or N-vinylpyrrolidone may be added. The polymerization solution after termination of the polymerization reaction can recover the target S-SBR by separating the solvent by direct drying, steam stripping or the like. In addition, before removing the solvent, the polymerization solution and the extending oil may be mixed in advance and recovered as an oil-extended rubber.

(Iii) Modified styrene butadiene rubber (modified SBR)
In the present invention, modified SBR in which a functional group is introduced into SBR may be used. Examples of the functional group include an amino group, an alkoxysilyl group, a hydroxy group, an epoxy group, and a carboxyl group.
As a method for producing the modified SBR, for example, before adding a polymerization terminator, tin tetrachloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, which can react with a polymerization active terminal, Coupling agents such as 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, 4,4′-bis (diethylamino) benzophenone, N-vinylpyrrolidone, etc. Or a method of adding other modifiers described in JP2011-132298A.
In this modified SBR, the position of the polymer into which the functional group is introduced may be the polymerization terminal or the side chain of the polymer chain.

(Isoprene rubber (A-II))
Examples of the isoprene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; -Commercially available isoprene rubber polymerized by using a lanthanoid rare earth metal catalyst such as an organic acid neodymium-Lewis acid type or an organic alkali metal compound in the same manner as S-SBR can be used. Isoprene rubber polymerized with a Ziegler catalyst is preferred because of its high cis isomer content. Further, isoprene rubber having an ultra-high cis body content obtained using a lanthanoid rare earth metal catalyst may be used.

The vinyl content of the isoprene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the rolling resistance performance tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −20 ° C. or lower, and more preferably −30 ° C. or lower.
The weight average molecular weight (Mw) of isoprene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is in the above range, workability and mechanical strength are good.
The isoprene rubber is partly composed of a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a branched structure or a polar functional group.

(Butadiene rubber (A-III))
Examples of the butadiene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; -Commercially available butadiene rubber polymerized using a lanthanoid rare earth metal catalyst such as organic acid neodymium-Lewis acid or the like, or an organic alkali metal compound in the same manner as S-SBR can be used. Butadiene rubber polymerized with a Ziegler catalyst is preferred because of its high cis isomer content. Moreover, you may use the butadiene rubber of the ultra high cis body content obtained using a lanthanoid type rare earth metal catalyst.
The vinyl content of the butadiene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the rolling resistance performance tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −40 ° C. or lower, and more preferably −50 ° C. or lower.
The weight average molecular weight (Mw) of the butadiene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is in the above range, workability and mechanical strength are good.
A part of the butadiene rubber is a polyfunctional type modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a branched structure or a polar functional group.

Along with at least one of SBR, isoprene rubber, and butadiene rubber, one or more of butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber and the like can be used. Moreover, these manufacturing methods are not specifically limited, What is marketed can be used.
In the present invention, the combined use of SBR, isoprene rubber, butadiene rubber and other synthetic rubbers with filler (B) and farnesene modified farnesene polymer (C) described later, rolling resistance performance, steering stability, mechanical strength, Abrasion resistance can be improved.
When two or more kinds of synthetic rubbers are mixed and used, the combination can be arbitrarily selected within a range not impairing the effects of the present invention, and the physical properties such as rolling resistance performance and wear resistance can be adjusted by the combination.

[Natural rubber]
Examples of the natural rubber used in the rubber component (A) include TSR such as SMR, SIR, and STR, natural rubber generally used in the tire industry such as RSS, high-purity natural rubber, epoxidized natural rubber, and hydroxylation. Examples thereof include modified natural rubber such as natural rubber, hydrogenated natural rubber, and grafted natural rubber. Among these, SMR20, STR20, and RSS # 3 are preferable from the viewpoint of little variation in quality and easy availability. These may be used alone or in combination of two or more.
In addition, there is no restriction | limiting in particular in the manufacturing method of the rubber | gum used for a rubber component (A), You may use a commercially available thing.

<Filler (B)>
The rubber composition of the present invention contains 20 to 150 parts by mass of filler (B) with respect to 100 parts by mass of the rubber component (A). By using the filler (B), physical properties such as mechanical strength in the crosslinked product of the rubber composition are improved.
As the filler (B) in the present invention, it is preferable to use at least one of carbon black and silica.
〔Carbon black〕
As the carbon black, for example, carbon black such as furnace black, channel black, thermal black, acetylene black, and ketjen black can be used. Among these, furnace black is preferable from the viewpoint of improving the vulcanization speed of the rubber composition and the mechanical strength of the vulcanized product. These carbon blacks may be used alone or in combination of two or more.
The average particle size of the carbon black is preferably 5 to 100 nm, more preferably 5 to 80 nm, and still more preferably 5 to 70 nm, from the viewpoint of improving dispersibility, mechanical strength, and hardness.
As a commercial product of furnace black, Mitsubishi Chemical Corporation "Dia Black", Tokai Carbon Co., Ltd. "Seast" etc. are mentioned, for example. Examples of commercially available acetylene black include “DENKA BLACK” manufactured by Denki Kagaku Kogyo Co., Ltd. Examples of commercially available ketjen black include “ECP600JD” manufactured by Lion Corporation.

From the viewpoint of improving wettability and dispersibility in the rubber component (A) and the modified farnesene polymer (C), the carbon black is acid-treated with nitric acid, sulfuric acid, hydrochloric acid, or a mixed acid thereof, or in the presence of air. Surface oxidation treatment by heat treatment in may be performed. Moreover, you may heat-process at 2,000-3,000 degreeC in presence of a graphitization catalyst from a viewpoint of the mechanical strength improvement of the rubber composition of this invention. Examples of the graphitization catalyst include boron, boron oxide (for example, B ₂ O ₂ , B ₂ O ₃ , B ₄ O ₃ , B ₄ O ₅ ), boron oxoacid (for example, orthoboric acid, metaboric acid, Tetraboric acid etc.) and salts thereof, boron carbide (eg B ₄ C, B ₆ C etc.), boron nitride (BN), and other boron compounds are preferably used.

The particle size of carbon black can be adjusted by pulverization or the like. For carbon black pulverization, high-speed rotary pulverizer (hammer mill, pin mill, cage mill), various ball mills (rolling mill, vibration mill, planetary mill), stirring mill (bead mill, attritor, distribution pipe mill, annular mill) Etc. can be used.
The average particle size of carbon black can be determined by measuring the particle diameter with a transmission electron microscope and calculating the average value.

〔silica〕
Examples of silica include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate. Among these, wet silica is preferable from the viewpoint of further improving workability, mechanical strength, and wear resistance. These may be used alone or in combination of two or more.
The average particle diameter of the silica is 0.5 to 200 nm from the viewpoint of improving the processability of the resulting rubber composition, the mechanical strength and wear resistance of the crosslinked product, and the rolling resistance performance of tires and the like using the crosslinked product. Preferably, 5-150 nm is more preferable, and 10-100 nm is still more preferable.
The average particle diameter of silica can be determined by measuring the diameter of the particles with a transmission electron microscope and calculating the average value.

  Content of the filler (B) with respect to 100 mass parts of rubber components (A) is 20-150 mass parts, 25-130 mass parts is preferable and 25-100 mass parts is more preferable. When the content of the filler (B) is within the above range, the processability of the rubber composition, the mechanical strength and wear resistance of the crosslinked product, and the rolling resistance performance of a tire or the like using the crosslinked product are improved.

[Other fillers]
The rubber composition of the present invention is used for the purpose of improving the mechanical strength of the cross-linked product, improving physical properties such as heat resistance and weather resistance, adjusting the hardness, and improving the economic efficiency by adding an extender, as necessary. In addition, fillers other than carbon black and silica may be further contained.

The filler other than the carbon black and silica is appropriately selected depending on the application. For example, an organic filler, clay, talc, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, titanium oxide. One or more selected from inorganic fillers such as glass fiber, fibrous filler, and glass balloon can be used.
When the rubber composition of this invention contains fillers other than the said carbon black and a silica, the content is 0.1-120 mass parts with respect to 100 mass parts of rubber components (A), 5-90 is preferable. A mass part is more preferable, and 10-80 mass parts is still more preferable. When the content of the filler is within the range, the mechanical strength of the crosslinked product is further improved.

<Vulcanizing agent>
The rubber composition of the present invention preferably contains a vulcanizing agent. Examples of the vulcanizing agent include sulfur and sulfur compounds. These may be used alone or in combination of two or more. When the vulcanizing agent is contained, the content thereof is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component (A), and 0.8 -5 mass parts is still more preferable.

<Vulcanization accelerator>
The rubber composition of the present invention may contain a vulcanization accelerator. Examples of the vulcanization accelerator include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds or aldehyde-ammonia compounds, imidazoline compounds. Compounds, xanthate compounds, and the like. These may be used alone or in combination of two or more. When it contains the said vulcanization accelerator, 0.1-15 mass parts is preferable with respect to 100 mass parts of rubber components (A), and 0.1-10 mass parts is more preferable.

<Vulcanization aid>
The rubber composition of the present invention may contain a vulcanization aid. Examples of the vulcanization aid include fatty acids such as stearic acid, metal oxides such as zinc white, and fatty acid metal salts such as zinc stearate. These may be used alone or in combination of two or more. When the said vulcanization | cure adjuvant is contained, 0.1-15 mass parts is preferable with respect to 100 mass parts of rubber components (A), and 1-10 mass parts is more preferable.

<Silane coupling agent>
When silica is used in the rubber composition of the present invention, it is preferable to contain a silane coupling agent. Examples of the silane coupling agent include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidoxy compounds, nitro compounds, and chloro compounds.
Examples of sulfide compounds include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, and bis (2-trimethoxy). Silylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) Disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, -Dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, etc. Can be mentioned.
Examples of the mercapto compound include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like.
Examples of the vinyl compound include vinyl triethoxysilane and vinyl trimethoxysilane.
Examples of amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, and 3- (2-aminoethyl) aminopropyltrimethoxy. Silane etc. are mentioned.
Examples of glycidoxy compounds include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane. Can be mentioned.
Examples of the nitro compound include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.
Examples of the chloro compound include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, and the like.
These silane coupling agents may be used alone or in combination of two or more. Of these, silane coupling agents containing sulfur such as sulfide compounds and mercapto compounds are preferred from the viewpoint of a large reinforcing effect, and bis (3-triethoxysilylpropyl) disulfide and bis (3-triethoxysilylpropyl) tetra Sulfide and 3-mercaptopropyltrimethoxysilane are more preferable.

  When the silane coupling agent is contained, the content of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of silica. 15 parts by mass is more preferable. When the content of the silane coupling agent is within the above range, dispersibility, reinforcement, and abrasion resistance are improved.

<Other ingredients>
The rubber composition of the present invention is intended to improve processability, fluidity and the like within a range that does not impair the effects of the invention, and if necessary, silicon oil, aroma oil, TDAE (Treated Distilled Aromatic Extracts), MES (Mild) Extracted Solvates), RAE (Residual Aromatic Extracts), paraffin oil, naphthenic oil and other process oils, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, C9 resins, rosin resins, coumarone / indene resins, phenolic resins Resin component such as resin, low molecular weight polybutadiene, low molecular weight polyisoprene, low molecular weight styrene butadiene copolymer, liquid polymer such as low molecular weight styrene isoprene copolymer, unmodified farnesene polymer as softener Also good. The copolymer may be in any polymerization form such as block or random. The weight average molecular weight (Mw) of the liquid polymer is preferably 500 to 100,000 from the viewpoint of processability. When the rubber composition of the present invention contains the above process oil, resin component or liquid polymer, and unmodified farnesene polymer as a softening agent, the content is 50 masses per 100 mass parts of the rubber component (A). The amount is preferably less than the part.

The rubber composition of the present invention is an anti-aging agent, an antioxidant, a wax, a lubricant, a light as needed for the purpose of improving the weather resistance, heat resistance, oxidation resistance, etc., as long as the effects of the invention are not impaired. Stabilizers, scorch inhibitors, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, mold release agents, foaming agents, antibacterial agents, fungicides 1 type, or 2 or more types of additives, such as an agent and a fragrance | flavor, may be contained.
Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, lactone compounds, hydroxyl compounds, and the like.
Examples of the antiaging agent include amine-ketone compounds, imidazole compounds, amine compounds, phenolic compounds, sulfur compounds, and phosphorus compounds.

  The method for producing the rubber composition of the present invention is not particularly limited, and the components may be mixed uniformly. Examples of the uniform mixing method include, for example, a tangential or meshing type closed kneader such as a kneader ruder, brabender, banbury mixer, internal mixer, single screw extruder, twin screw extruder, mixing roll, roller, etc. Usually, and can be performed in a temperature range of 70 to 270 ° C.

  The rubber composition of the present invention can be used as a vulcanized rubber by vulcanization. There are no particular restrictions on the vulcanization conditions and method, but it is preferably carried out using a vulcanization mold under a vulcanization temperature of 120 to 200 ° C. and a vulcanization pressure of 0.5 to 2.0 MPa.

  The rubber composition of the present invention can be used after being crosslinked by adding a crosslinking agent in addition to the above vulcanizing agent. Examples of the cross-linking agent include oxygen, organic peroxide, phenol resin and amino resin, quinone and quinonedioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides and organometallic halides, and silane compounds. Etc. These may be used alone or in combination of two or more. As for content of a crosslinking agent, 0.1-10 mass parts is preferable with respect to 100 mass parts of rubber components (A).

[tire]
The tire of the present invention uses at least a part of the rubber composition of the present invention. Therefore, the mechanical strength is good and it has excellent rolling resistance performance. Furthermore, the tire using the rubber composition of the present invention can maintain the characteristics such as the mechanical strength even when used for a long time.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.
Each component used in the examples and comparative examples is as follows.
<Rubber component (A)>
・ Natural rubber: "STR20" (Thai natural rubber) (A-1)
Oil-extended styrene butadiene rubber: “JSR1723” (manufactured by JSR Corporation) (A-2)
Weight average molecular weight (Mw) = 850,000
Styrene content = 23.5% by mass
Manufactured by emulsion polymerization
Oil content = 27.3%

<Filler (B)>
Silica: ULTRASIL 7000GR (Evonik Degussa Japan) (B-1)
Wet silica: Average particle size 14nm

<Modified farnesene polymer (C)>
-Modified farnesene polymers (C-1) to (C-4) produced according to the following production examples

<Polyisoprene>
Polyisoprene: Polyisoprene (X-1) and (X-2) obtained in Comparative Production Examples 1 and 2 below
<Comparison example of modified farnesene polymer (C ′)>
-Modified farnesene polymer (C'-1) produced according to the following Comparative Production Example 3

<Optional component>
TDAE: VivaTec500 (manufactured by H & R)
Silane coupling agent (1): Si75 (Evonik Degussa Japan)
Silane coupling agent (2): Si69 (Evonik Degussa Japan)
Anti-aging agent (1): NOCRACK 6C (manufactured by Ouchi Shinsei Chemical Co., Ltd.)
Anti-aging agent (2): ANTAGE RD (Kawaguchi Chemical Industry Co., Ltd.)
・ Wax: Suntite S (Seiko Chemical Co., Ltd.)

・ Vulcanizing agent Sulfur (fine powder sulfur 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.)
・ Vulcanization accelerator Vulcanization accelerator (1): Noxeller NS-P (Ouchi Shinsei Chemical Co., Ltd.)
Vulcanization accelerator (2): Noxeller CZ-G (Ouchi Shinsei Chemical Co., Ltd.)
Vulcanization accelerator (3): Noxeller D (Ouchi Shinsei Chemical Co., Ltd.)
Vulcanization accelerator (4): Noxeller TBT-N (Ouchi Shinsei Chemical Co., Ltd.)
・ Vulcanization aid Stearic acid: LUNAC S-20 (manufactured by Kao Corporation)
Zinc flower: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.)

Production Example 1: Production of modified farnesene polymer (C-1) A pressure-resistant vessel purged with nitrogen and dried was charged with 1370 g of hexane as a solvent and 6.0 g of n-butyllithium (17% by mass hexane solution) as an initiator. After raising the temperature to 50 ° C., 1360 g of β-farnesene was added and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerized reaction solution after washing and water were separated and dried under reduced pressure at 80 ° C. for 12 hours to obtain unmodified polyfarnesene.
Next, 500 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.5 g of NOCRACK 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, purged with nitrogen, heated to 170 ° C. and reacted for 24 hours. . Further, 9.0 g of methanol (1.1 equivalents with respect to maleic anhydride) was added and reacted at 80 ° C. for 6 hours to obtain a maleic acid monomethyl ester group (functional group 1) and a maleic anhydride group (functional group 2). A modified farnesene polymer (C-1) was obtained. Table 1 shows the physical properties of the modified farnesene polymer (C-1).

Production Example 2: Production of Modified Farnesene Polymer (C-2) Unmodified polyfarnesene was obtained in the same manner as in Production Example 1.
Next, 500 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.5 g of NOCRACK 6C as an anti-aging agent, and 7.5 g of maleic anhydride were charged, purged with nitrogen, heated to 170 ° C., and reacted for 24 hours. I let you. Further, 2.7 g of methanol (1.1 equivalent with respect to maleic anhydride) was added and reacted at 80 ° C. for 6 hours to obtain a maleic acid monomethyl ester group (functional group 1) and a maleic anhydride group (functional group 2). A modified farnesene polymer (C-2) was obtained. Table 1 shows the physical properties of the modified farnesene polymer (C-2).

Production Example 3 Production of Modified Farnesene Polymer (C-3) In a pressure-resistant container purged with nitrogen and dried, 1200 g of cyclohexane as a solvent and 42.6 g of sec-butyllithium (10.5 mass% cyclohexane solution) as an initiator Was heated to 50 ° C., 1880 g of β-farnesene was added, and polymerization was performed for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerized reaction solution after washing and water were separated and dried under reduced pressure at 80 ° C. for 12 hours to obtain unmodified polyfarnesene.
Next, 500 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.5 g of NOCRACK 6C as an anti-aging agent, and 7.5 g of maleic anhydride were charged, purged with nitrogen, heated to 170 ° C., and reacted for 24 hours. I let you. Further, 2.7 g of methanol (1.1 equivalent with respect to maleic anhydride) was added and reacted at 80 ° C. for 6 hours to obtain a maleic acid monomethyl ester group (functional group 1) and a maleic anhydride group (functional group 2). A modified farnesene polymer (C-3) was obtained. Table 1 shows the physical properties of the modified farnesene polymer (C-3).

Production Example 4: Production of modified farnesene polymer (C-4) 1137 g of hexane as a solvent and 32.8 g of sec-butyllithium (10.5 mass% cyclohexane solution) as an initiator in a pressure-resistant container purged with nitrogen and dried. And heated to 50 ° C., and then a mixture of β-farnesene (c1) and butadiene (c2) prepared in advance (1260 g of β-farnesene (c1) and 840 g of butadiene (c2) mixed in a cylinder) 1430 g Was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain an unmodified farnesene-butadiene copolymer.
Next, 500 g of the unmodified farnesene-butadiene copolymer obtained in the pressure vessel, 0.5 g of Nocrack 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, and after nitrogen substitution, the temperature was raised to 170 ° C. The reaction was performed for 24 hours. Further, 9.0 g of methanol (1.1 equivalents with respect to maleic anhydride) was added and reacted at 80 ° C. for 6 hours to obtain a maleic acid monomethyl ester group (functional group 1) and a maleic anhydride group (functional group 2). A modified farnesene polymer (C-4) was obtained. Table 1 shows the physical properties of the modified farnesene polymer (C-4).

Comparative production example 1: Production of polyisoprene (X-1) A pressure-resistant container purged with nitrogen and dried was charged with 600 g of hexane and 13.9 g of n-butyllithium (17% by mass hexane solution) and heated to 70 ° C. Then, 1,370 g of isoprene was added and polymerization was performed for 1 hour. After adding methanol to the obtained polymerization reaction solution, the polymerization reaction solution was washed with water. Water was separated, and the polymerization reaction solution was dried under reduced pressure at 80 ° C. for 12 hours to obtain polyisoprene (X-1) having physical properties shown in Table 1.

Comparative Production Example 2: Production of polyisoprene (X-2) 600 g of hexane and 44.9 g of n-butyllithium (17% by mass hexane solution) were charged into a pressure vessel that had been purged with nitrogen and dried, and the temperature was raised to 70 ° C Then, 2,050 g of isoprene was added and polymerized for 1 hour. After adding methanol to the obtained polymerization reaction solution, the polymerization reaction solution was washed with water. Water was separated, and the polymerization reaction solution was dried under reduced pressure at 80 ° C. for 12 hours to obtain polyisoprene (X-2) having physical properties shown in Table 1.

Comparative production example 3: Production of modified farnesene polymer (C′-1) In a pressure-resistant container purged with nitrogen and dried, 5755 g of hexane as a solvent and 26.5 g of n-butyllithium (17 mass% hexane solution) as an initiator Was heated to 50 ° C., 5709 g of β-farnesene was added, and polymerization was performed for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain unmodified polyfarnesene.
Next, 500 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.5 g of NOCRACK 6C as an anti-aging agent, and 25 g of maleic anhydride are charged, and after purging with nitrogen, the temperature is raised to 170 ° C. and reacted for 24 hours. As a result, a modified farnesene polymer (C′-1) having a maleic anhydride group was obtained. Table 1 shows the physical properties of the modified farnesene polymer (C′-1).

The weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), melt viscosity, glass transition temperature, functional group 1 content and functional groups of the modified farnesene polymers (C), (C ′) and polyisoprene. The method for measuring the total amount of is as follows.
(Method of measuring weight average molecular weight and molecular weight distribution)
Mw and Mw / Mn of the modified farnesene polymers (C) and (C ′) and polyisoprene were determined by GPC (gel permeation chromatography) in terms of standard polystyrene equivalent molecular weight. The measuring apparatus and conditions are as follows.
・ Device: GPC device “GPC8020” manufactured by Tosoh Corporation
Separation column: “TSKgel G4000HXL” manufactured by Tosoh Corporation
Detector: “RI-8020” manufactured by Tosoh Corporation
・ Eluent: Tetrahydrofuran ・ Eluent flow rate: 1.0 ml / min ・ Sample concentration: 5 mg / 10 ml
-Column temperature: 40 ° C

(Measuring method of melt viscosity)
The melt viscosity of the modified farnesene polymers (C), (C ′) and polyisoprene at 38 ° C. was measured with a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

(Measurement method of glass transition temperature)
Ten mg of the modified farnesene polymer or polyisoprene is collected in an aluminum pan, a thermogram is measured under a temperature increase rate condition of 10 ° C./min by differential scanning calorimetry (DSC), and the peak top value of DDSC is determined as the glass transition temperature. did.

(Content ratio of functional group 1)
The modified farnesene polymer was applied on a KBr substrate and measured by a transmission method using a Fourier transform infrared spectrophotometer manufactured by JASCO Corporation. The content ratio of the functional group 1 was calculated from the intensity ratio of the peak derived from the ring structure of the maleic anhydride group (functional group 2) and the peak derived from the maleic acid monomethyl ester group (functional group 1).

(Total amount of functional groups in the modified farnesene polymer)
1) Acid value After adding 180 mL of toluene and 20 mL of ethanol to 3 g of the sample after the modification reaction and dissolving, neutralization titration with an ethanol solution of 0.1 N potassium hydroxide was performed to determine the acid value.
Acid value (mgKOH / g) = (A−B) × F × 5.661 / S
A: 0.1N potassium hydroxide ethanol solution drop required for neutralization (mL)
B: 0.1N potassium hydroxide ethanol solution drop volume in a blank containing no sample (mL)
F: Potency of ethanol solution of 0.1N potassium hydroxide S: Weight of sample weighed (g)

2) Content ratio of functional groups 1 and 2 From the acid value, the mass of the functional group contained per 1 g of the modified farnesene polymer (C) and the mass other than the functional group contained per 1 g (polymer main chain mass) were calculated. . Next, based on the following formula, the total amount of functional groups (content ratio of functional groups 1 and 2) in the modified farnesene polymer (C) was calculated (mass%).
[Mass of functional group 1 per gram of polymer] = [acid value] / [56.11] × [molecular weight of functional group 1] / 1000 × [content ratio of functional group 1]
[Mass of functional group 2 per gram of polymer] = [acid value] / [56.11] × [molecular weight of functional group 2] / 1000 × [content ratio of functional group 2]
[Mass of functional groups 1 and 2 per gram of polymer] = [Mass of functional group 1 per gram of polymer] + [Mass of functional group 2 per gram of polymer]
[Mass of polymer main chain per gram of polymer] = 1- [Mass of functional groups 1 and 2 per gram of polymer]
[Content ratio of functional groups 1 and 2] = [mass of functional groups 1 and 2 per gram of polymer] / [polymer main chain mass per gram of polymer] × 100

Example 1 and Comparative Examples 1 and 2
According to the blending ratio (parts by mass) described in Table 2, the rubber component (A), silica (B), modified farnesene polymer (C), polyisoprene (X), TDAE, vulcanization aid and anti-aging agent are added. Then, each was put into a closed Banbury mixer and kneaded for 6 minutes so that the starting temperature was 75 ° C. and the resin temperature was 160 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was put in a mixing roll, a vulcanizing agent and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain about 1.2 kg of a rubber composition.
The obtained rubber composition was press-molded (145 ° C., 45 minutes) to produce a vulcanized rubber sheet (thickness 2 mm), and the rolling resistance performance, hardness, and tensile breaking strength were evaluated based on the following methods. did. The results are shown in Table 2.
In addition, the measuring method of each evaluation is as follows.

-Rolling resistance performance A test piece of 40 mm length x 7 mm width was cut out from the rubber composition sheets produced in the examples and comparative examples, and measured using a dynamic viscoelasticity measuring device manufactured by GABO at a measurement temperature of 60 ° C and a frequency of 10 Hz. Tan δ was measured under the conditions of 10% static strain and 2% dynamic strain, and used as an index of rolling resistance. The numerical value of each Example and Comparative Example is a relative value when the value of Comparative Example 2 is set to 100. In addition, the rolling resistance performance of a rubber composition is so favorable that a numerical value is small.

・ Hardness (steering stability)
Using the rubber composition sheets prepared in Examples and Comparative Examples, the hardness was measured with a type A hardness meter in accordance with JIS K6253, and used as an index of flexibility. In addition, when a numerical value is smaller than 50, since the deformation | transformation of a tire is large when the said composition is used for a tire, steering stability deteriorates.

・ Tensile strength at break (mechanical strength)
Dumbbell-shaped test pieces were punched out from the rubber composition sheets prepared in Examples and Comparative Examples in accordance with JIS No. 3, and the tensile strength at break was measured in accordance with JIS K 6251 using an Instron tensile tester. The numerical value of each Example and Comparative Example is a relative value when the value of Comparative Example 2 is set to 100. Note that the larger the numerical value, the better the breaking property.

  The vulcanized rubber sheet produced from the rubber composition of Example 1 has better hardness, rolling resistance performance and mechanical strength than Comparative Examples 1 and 2 which do not contain the modified farnesene polymer (C) of the present invention. Since it is excellent, it can be suitably used as a rubber composition for tires.

Examples 2 to 5, Comparative Examples 3 and 4
According to the blending ratio (parts by mass) described in Table 3, the rubber component (A), silica (B), modified farnesene polymer (C), polyisoprene, TDAE, wax, vulcanization aid and anti-aging agent, Each was put into a closed Banbury mixer and kneaded for 6 minutes so that the starting temperature was 75 ° C. and the resin temperature was 160 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was put in a mixing roll, a vulcanizing agent and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain about 1.3 kg of a rubber composition.
The obtained rubber composition was press-molded (160 ° C., 30 minutes) to produce a vulcanized rubber sheet (thickness 2 mm), and the rolling resistance performance, hardness, and tensile breaking strength were evaluated based on the above methods. did. Moreover, the elastic modulus was evaluated based on the following method. The results are shown in Table 3.
In addition, the numerical values of the rolling resistance performance and the tensile strength at break in Table 3 are relative values when the value of Comparative Example 4 in Table 3 is 100.

-Elastic modulus A test piece of 40 mm length x 7 mm width was cut out from the rubber composition sheets produced in the examples and comparative examples, and measured using a dynamic viscoelasticity measuring device manufactured by GABO at a measurement temperature of 25 ° C, a frequency of 10 Hz, and a static pressure. The storage elastic modulus E ′ was measured under the conditions of a static strain of 10% and a dynamic strain of 2%, and used as an index of rigidity. The numerical value of each Example and Comparative Example is a relative value when the value of Comparative Example 4 is 100. In addition, the larger the numerical value, the smaller the deformation of the tire when the rubber composition is used for the tire, and the better the steering stability.

  The vulcanized rubber sheets produced from the rubber compositions of Examples 2 to 5 have a higher elastic modulus and rolling resistance performance and hardness than Comparative Examples 3 and 4 that do not contain the modified farnesene polymer (C) of the present invention. And excellent mechanical strength, it can be suitably used as a rubber composition for tires. Among these, the vulcanized rubber sheet produced from the rubber composition of Example 5 using a modified farnesene-butadiene copolymer is more excellent in rolling resistance performance and elastic modulus.

Example 6 and Comparative Example 5
According to the blending ratio (parts by mass) described in Table 4, rubber component (A), silica (B), modified farnesene polymer (C), modified farnesene polymer (C ′), TDAE, wax, vulcanization aid The anti-aging agent and the anti-aging agent were respectively put into a closed Banbury mixer and kneaded for 6 minutes so that the starting temperature was 75 ° C. and the resin temperature was 160 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was put in a mixing roll, a vulcanizing agent and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain about 1.3 kg of a rubber composition. The Mooney viscosity of the obtained rubber composition was measured by the following method.
Further, the obtained rubber composition is press-molded (160 ° C., 30 minutes) to produce a vulcanized rubber sheet (thickness 2 mm). Based on the above methods, rolling resistance performance, hardness, elastic modulus and tensile breaking strength are obtained. Evaluated.
In addition, the numerical values of rolling resistance performance, elastic modulus, and tensile strength at break in Table 4 are relative values when the value of Comparative Example 5 in Table 4 is set to 100.

Mooney viscosity As an index of processability of the rubber composition, the Mooney viscosity (ML _{1 + 4} ) of the rubber composition before vulcanization was measured at 100 ° C. in accordance with JIS K6300. The value of Example 6 is a relative value when the value of Comparative Example 5 is set to 100. In addition, workability is so favorable that a numerical value is small.

  The vulcanized rubber sheet produced from the rubber composition of Example 6, compared with Comparative Example 5 using a modified farnesene polymer in which the total amount of the functional groups (a1) to (a3) is outside the scope of the present invention, Since it has a high elastic modulus, excellent rolling resistance performance and hardness, and good mechanical strength, it can be suitably used as a rubber composition for tires. In addition, the rubber composition of Example 6 has good processability because of its low Mooney viscosity.

Claims (14)

A modified farnesene polymer having one or more functional groups selected from a dicarboxylic acid structure (a1), a dicarboxylic acid monoester structure (a2), a dicarboxylic acid monoamide structure (a3), and a carboxylic anhydride structure (a4), wherein (a1) Ri der least 80 mol% based on the total amount of the entire amount of ~ (a3) (a1) ~ (a4), the melt viscosity at 38 ° C. is 0.1~3,000Pa · s modified farnesene Polymer.   The modified farnesene polymer according to claim 1, wherein the dicarboxylic acid is maleic acid, the dicarboxylic acid monoester is maleic acid monoester, and the dicarboxylic acid monoamide is maleic acid monoamide.   The modified farnesene polymer according to claim 1 or 2, wherein the dicarboxylic acid monoester is at least one selected from dicarboxylic acid monomethyl ester, dicarboxylic acid monoethyl ester, dicarboxylic acid monopropyl ester, and dicarboxylic acid monobutyl ester. .   The modified farnesene polymer according to any one of claims 1 to 3, wherein the total amount of the (a1) to (a4) in the modified farnesene polymer is 0.1 to 50% by mass. The modified farnesene polymer according to any one of claims 1 to 4 , having a weight average molecular weight of 2,000 to 500,000. It has one or more functional groups selected from a dicarboxylic acid structure (a1), a dicarboxylic acid monoester structure (a2), a dicarboxylic acid monoamide structure (a3), and a carboxylic anhydride structure (a4), and the above (a1) to ( A method for producing a modified farnesene polymer in which the total amount of a3) is 80 mol% or more based on the total amount of (a1) to (a4), wherein the carboxylic anhydride portion of the farnesene polymer modified with carboxylic anhydride is obtained. A method for producing a modified farnesene polymer that undergoes a ring-opening reaction. A rubber composition containing 20 to 150 parts by mass of filler (B) with respect to 100 parts by mass of one or more rubber components (A) selected from synthetic rubber and natural rubber, and 100 parts by mass of filler (B) On the other hand, it has one or more functional groups selected from a dicarboxylic acid structure (a1), a dicarboxylic acid monoester structure (a2), a dicarboxylic acid monoamide structure (a3), and a carboxylic anhydride structure (a4), ) To (a3) A rubber composition containing 0.1 to 30 parts by mass of the modified farnesene polymer (C) in which the total amount of (a1) to (a4) is 80 mol% or more . The rubber composition according to claim 7 , wherein the filler (B) is at least one selected from carbon black and silica. The rubber composition according to claim 8 , wherein the carbon black has an average particle size of 5 to 100 nm and the silica has an average particle size of 0.5 to 200 nm. The rubber composition according to claim 8 or 9 , comprising 0.1 to 30 parts by mass of a silane coupling agent with respect to 100 parts by mass of the silica. The rubber composition according to any one of claims 7 to 10 , wherein the synthetic rubber is at least one selected from styrene butadiene rubber, butadiene rubber, and isoprene rubber. The rubber composition according to claim 11 , wherein the styrene-butadiene rubber has a weight average molecular weight of 100,000 to 2.5 million. The rubber composition according to claim 11 or 12 , wherein the styrene-butadiene rubber has a styrene content of 0.1 to 70 mass%. A tire using at least a part of the rubber composition according to any one of claims 7 to 13 .