JP2016037588A - Rubber composition and tire containing modified farnesene polymer, and method for producing modified farnesene polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition containing modified farnesene polymer, that can improve the dispersibility of fillers such as carbon black or silica when used in a part of the rubber composition, and that is excellent in rolling resistance performance, steering stability resulting from the high hardness, wear resistance, and mechanical strength, and to provide a tire using the rubber composition as well as a method for producing the modified farnesene polymer.SOLUTION: There is provided a rubber composition containing 20 to 150 pts.mass of one or more of filler (B) selected from carbon black and silica, and 0.1 to 30 pts.mass of modified farnesene polymer (C) comprising a monomer unit derived from farnesene, per 100 pts.mass of one or more of rubber component (A) selected from synthetic rubber and natural rubber, and in which the modified farnesene polymer (C) satisfies the conditions (I) and (II).SELECTED DRAWING: None

Description

  The present invention relates to a rubber composition containing a modified farnesene polymer containing a farnesene-derived monomer unit, a tire using the rubber composition, and a method for producing the modified farnesene polymer.

Conventionally, a rubber composition that has improved mechanical strength by adding a reinforcing agent such as carbon black or silica to a rubber component such as natural rubber or styrene butadiene rubber requires a wear resistance and mechanical strength. Widely used in applications.
It is known that the reinforcing agent exhibits its reinforcing effect by physically or chemically adsorbing the rubber component on the particle surface. Therefore, when a reinforcing agent having an average particle size of about 100 to 200 nm is used, the interaction with the rubber component is generally not sufficiently obtained, so that the mechanical strength of the rubber composition is sufficiently improved. There was a case that could not be. 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 reinforcing agent having a small average particle diameter of about 5 to 100 nm and a large specific surface area is used, the interaction between the reinforcing agent and the rubber component increases, so the mechanical strength and abrasion resistance of the rubber composition, etc. Improved characteristics. 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 reinforcing agent having a small average particle diameter is used, the dispersibility of the reinforcing agent in the rubber composition is lowered due to a high cohesive force between carbon black or silica. This decrease in the dispersibility of the reinforcing agent may cause a long time for the kneading process and 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.
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 discloses 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. in a specific ratio. The rubber composition for tires contained in 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. Is 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

Even in the tires described in Patent Documents 1 and 2, it cannot be said that the mechanical strength, the hardness, and the steering stability resulting from the hardness and the rolling resistance performance are sufficiently high, and further improvement is desired. It is rare.
The present invention has been made in view of the above circumstances, and contains a modified farnesene polymer capable of improving the dispersibility of fillers such as carbon black and silica when used as part of a rubber composition. Provided is a rubber composition, the crosslinked product of which has excellent hardness, mechanical strength, and abrasion resistance.
The present invention also provides a tire having at least a portion of the rubber composition and having excellent steering stability and excellent rolling resistance performance due to high hardness, and a method for producing the modified farnesene polymer.

  As a result of intensive studies, the inventors of the present invention use a modified farnesene polymer that exhibits specific characteristics by gel permeation chromatography analysis in a modified farnesene polymer containing monomer units derived from farnesene. And it discovered that the crosslinked material of the said rubber composition showed the performance outstanding about hardness, mechanical strength, and abrasion resistance, and completed this invention.

That is, the gist of the present invention is the following [1] to [3].
[1] 20 to 150 parts by mass of one or more fillers (B) selected from carbon black and silica with respect to 100 parts by mass of one or more rubber components (A) selected from synthetic rubber and natural rubber, and A rubber composition containing 0.1 to 30 parts by mass of a modified farnesene polymer (C) containing a monomer unit derived from farnesene, wherein the modified farnesene polymer (C) comprises the following conditions (I) and (II A rubber composition satisfying
Condition (I): A modified farnesene polymer having a melt viscosity at 38 ° C. of 0.1 to 3,000 Pa · s.
Condition (II): The maximum peak molecular weight (Mt) in gel permeation chromatography (GPC) is 3,000 to 550,000, and the total area derived from the polymer in the GPC chromatogram is 100%. A modified farnesene polymer having an area ratio of a polymer having a molecular weight of 45 or more of 0 to 20%.
[2] A tire using at least a part of the rubber composition according to [1].
[3] 0.1 to 100 parts by mass of a modifier and 0.01 to 10 parts by mass of an anti-aging agent are added to 100 parts by mass of a polymer containing a monomer unit derived from farnesene, and 130 to 200 ° C. A method for producing a modified farnesene polymer, wherein the reaction is carried out at 0 ° C.

According to the present invention, a rubber composition containing a modified farnesene polymer capable of improving the dispersibility of a filler such as carbon black or silica when used in a part of the rubber composition, the crosslinked It is possible to provide a rubber composition that exhibits excellent hardness, mechanical strength, and wear resistance.
Further, it is possible to provide a tire having excellent handling stability and excellent rolling resistance performance due to high hardness, and a method for producing the modified farnesene polymer, using the rubber composition at least in part.

  The rubber composition of the present invention is a rubber composition containing a rubber component (A) composed of one or more selected from synthetic rubber and natural rubber, a filler (B), and a modified farnesene polymer (C). According to the rubber composition of the present invention, since the modified farnesene polymer (C) is contained, the crosslinked product of the rubber composition exhibits excellent hardness, mechanical strength, and wear resistance. Furthermore, when this crosslinked product is used for tire applications, it exhibits excellent rolling resistance performance. Hereinafter, each component will be described in detail.

<Rubber component (A)>
Examples of the rubber component (A) used in the rubber composition of the present invention include styrene butadiene rubber (hereinafter also referred to as “SBR”), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene rubber, butadiene acrylonitrile copolymer. One or more selected from synthetic rubbers such as coalesced rubber and chloroprene rubber and natural rubber. These rubbers may be used alone or in combination of two or more.

[Synthetic rubber]
When a synthetic rubber is used as the rubber component (A) in the present invention, SBR, butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber and the like are preferable, and among them, SBR, Isoprene rubber and butadiene rubber are more preferable, and SBR is more preferable.

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) determined by differential thermal analysis of SBR used in the present invention is preferably -95 to 0 ° C, more preferably -95 to -5 ° C. By setting Tg within the above range, it is possible to suppress an increase in viscosity, and handling becomes easy.

  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, 0-100 degreeC is preferable normally and 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 −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.

  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.
A part of the isoprene rubber is 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.

Examples of 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.

  As butyl rubber, halogenated butyl rubber, ethylene propylene rubber (EPM, EPDM, etc.), butadiene acrylonitrile copolymer rubber, and chloroprene rubber, commercially available products can be used without particular limitation. These can be used alone or in combination of two or more.

[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. There is no restriction | limiting in particular in the manufacturing method of these natural rubbers, You may use a commercially available thing.
In the present invention, among the rubber component (A), at least one selected from natural rubber, styrene butadiene rubber, butadiene rubber, and isoprene rubber is preferable.

In the present invention, the rubber component (A) contains a filler (B) and a modified farnesene polymer (C) described later, thereby improving the mechanical strength and abrasion resistance of the crosslinked product of the rubber composition. Moreover, the rolling resistance performance and steering stability of a tire using the crosslinked product can be improved.
When two or more rubber components (A) are mixed and used, the combination can be arbitrarily selected within a range not impairing the effects of the present invention, and the combination can provide physical property values such as rolling resistance performance and wear resistance. Can be adjusted.

<Filler (B)>
The filler (B) used in the rubber composition of the present invention is one or more fillers selected from carbon black and silica. By using the filler (B), physical properties such as mechanical strength in the crosslinked product of the rubber composition are improved.
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 carbon black having an average particle diameter of 5 to 100 nm, examples of commercially available products of furnace black include “Dia Black” manufactured by Mitsubishi Chemical Corporation, “Seast” manufactured by Tokai Carbon Co., Ltd., and the like. 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 diameter of carbon black can be determined by measuring the diameter of the particles with a transmission electron microscope and calculating the average value.

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 silica is 0.5 to 200 nm from the viewpoint of improving processability of the resulting rubber composition, mechanical strength and abrasion resistance of the crosslinked product, and rolling resistance performance of a tire or 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 particle diameter with a transmission electron microscope and calculating the average value.

In the rubber composition of the present invention, the content of the filler (B) with respect to 100 parts by mass of the rubber component (A) is 20 to 150 parts by mass, preferably 25 to 130 parts by mass, and more preferably 25 to 110 parts by mass. . 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.
Among these fillers (B), silica is more preferable from the viewpoint of improving rolling resistance performance of a tire or the like using a crosslinked product. Moreover, these fillers (B) may be used individually by 1 type, and may be used together 2 or more types.

[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 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.

<Modified farnesene polymer (C)>
The modified farnesene polymer (C) used in the rubber composition of the present invention reacts with a polymer containing a monomer unit derived from farnesene (hereinafter also referred to as “unmodified farnesene polymer”). The modified farnesene polymer is modified by introducing a functional group and satisfies the following conditions (I) and (II).
Condition (I): A modified farnesene polymer having a melt viscosity at 38 ° C. of 0.1 to 3,000 Pa · s.
Condition (II): The maximum peak molecular weight (Mt) in gel permeation chromatography (GPC) is 3,000 to 550,000, and the total area derived from the polymer in the GPC chromatogram is 100%. A modified farnesene polymer having an area ratio of a polymer having a molecular weight of 45 or more of 0 to 20%.

  As the farnesene constituting the modified farnesene polymer (C) in the present invention, one or more selected from α-farnesene and β-farnesene represented by the formula (I) can be used, from the viewpoint of ease of production. It is preferable to use β-farnesene.

The unmodified farnesene polymer may be composed only of monomer units derived from farnesene, and composed of monomer units derived from farnesene and monomer units derived from monomers other than farnesene. May be.
When the unmodified farnesene polymer is a copolymer, examples of monomer units 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.

  The ratio of monomer units other than farnesene to the total of monomer units derived from monomers other than farnesene and monomer units derived from farnesene in the copolymer is the processing of the resulting rubber composition. 1 to 99 mass% is preferable, 10 to 80 mass% is more preferable, and 15 to 70 mass% is still more preferable, from the viewpoint of improving the rolling resistance performance of a tire or the like using a crosslinked product of a rubber composition.

(Method for producing unmodified farnesene polymer)
The unmodified farnesene polymer can be produced by an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, a solution polymerization method, a method described in International Publication No. 2010/027463, International Publication No. 2010/027464, or the like. it can. 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 0 to 100 ° C, more preferably 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, in a solvent, a farnesene monomer is polymerized in the presence of a polar compound as desired using a polymerization catalyst such as a Ziegler catalyst, a metallocene catalyst, or an anion-polymerizable active metal.
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, Aromatic hydrocarbons such as toluene and xylene are exemplified.
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.

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 −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 polymerization reaction can be stopped by adding a polymerization terminator. Examples of the polymerization terminator include alcohols such as methanol and isopropanol. The farnesene polymer can be isolated by pouring the obtained polymerization reaction solution into a poor solvent such as methanol to precipitate the unmodified farnesene polymer, or washing the polymerization reaction solution with water, separating, and drying. .

[Modification method of unmodified farnesene polymer]
The modified farnesene polymer (C) can be obtained by reacting the unmodified farnesene polymer with a modifier and introducing a functional group. For example, a method (I) of adding a modifier such as tetraethoxysilane, carbon dioxide, ethylene oxide or the like that can react with the polymerization active terminal before adding a polymerization terminator, or after adding a polymerization terminator, unmodified It can be obtained by a modification method such as the method (II) of grafting a modifying agent such as maleic anhydride onto the farnesene polymer.

As the functional group introduced into the unmodified farnesene polymer, for example, carboxy group, sulfonyl group, alkoxysilyl group, acryloyl group, methacryloyl group, epoxy group, oxetanyl group, vinyl ether group, amino group, ammonium group, Amide group, imino group, imidazole group, urea group, silanol group, hydroxy group, ether group, carbonyl group, carboxylic acid ester group, sulfonic acid group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, mercapto group, Examples thereof include an isocyanate group, a nitrile group, a silicon halide group, a tin halide group, and a functional group derived from a carboxylic anhydride. Among these, what has 1 or more types of functional groups chosen from the functional group derived from carboxylic anhydride and an alkoxy silyl group is preferable.
As the functional group derived from the carboxylic anhydride, a functional group derived from one or more selected from maleic anhydride, citraconic anhydride, itaconic anhydride and succinic anhydride is preferable, and a functional group derived from maleic anhydride is more preferable. preferable.
In addition, about the position of the polymer in which a functional group is introduce | transduced in modified | denatured farnesene polymer (C), a polymerization terminal may be sufficient and the side chain of a polymer chain may be sufficient. Moreover, the said functional group may contain 1 type independently, and may contain 2 or more types. Therefore, the modified farnesene polymer (C) may be modified with one type of modifying agent or may be modified with two or more types of modifying agents.

  Examples of the modifier that can be used in the method (I) include tin tetrachloride, dibutyltin chloride, dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, and tetraglycidyl- 1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, carbon dioxide, ethylene oxide, succinic anhydride, 4,4′-bis (diethylamino) benzophenone, N-vinylpyrrolidone, N-methylpyrrolidone, 4- Modification agents such as dimethylaminobenzylideneaniline and dimethylimidazolidinone, cyclic ethers such as epoxide and oxetane, cyclic amines such as pyrrolidine, and modification agents such as cyclic sulfides such as ethylene sulfide, and JP 2011-132298 A That Other modifiers can be mentioned.

The amount of the modifier used in the method (I) is not particularly limited, but is preferably 0.01 to 100 molar equivalents relative to the polymerization catalyst used for producing the unmodified farnesene polymer. The reaction temperature is usually from -80 to 150 ° C, preferably from 0 to 100 ° C, more preferably from 10 to 90 ° C.
Further, after adding a functional group to the unmodified farnesene polymer by adding a modifier before adding the polymerization terminator, another functional group can be added by adding a modifier capable of reacting with the functional group. May be introduced into the polymer.

  Examples of the modifier that can be used in the method (II) include unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, itaconic anhydride; maleic acid, fumaric acid, Unsaturated carboxylic acids such as citraconic acid, itaconic acid and (meth) acrylic acid; unsaturated maleic acid ester, fumaric acid ester, citraconic acid ester, itaconic acid ester, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate, etc. Carboxylic acid esters; unsaturated carboxylic acid amides such as maleic acid amide, fumaric acid amide, citraconic acid amide and itaconic acid amide; unsaturated carboxylic acid imides such as maleic acid imide, fumaric acid imide, citraconic acid imide and itaconic acid imide; Maleimide, vinyltrimethoxysilane, γ -Methacryloxypropyltrimethoxysilane, methyldimethoxysilane and the like.

In the method (II), the method for grafting the modifying agent to the unmodified farnesene polymer is not particularly limited. For example, the unmodified farnesene polymer, a modifying agent such as an unsaturated carboxylic acid, and the like, if necessary. Then, a method of adding a radical catalyst and heating in the presence or absence of an organic solvent can be employed. The reaction temperature is usually 0 to 200 ° C, more preferably 50 to 200 ° C, further preferably 130 to 200 ° C, and still more preferably 140 to 180 ° C.
Examples of the organic solvent used in the above method generally include hydrocarbon solvents and halogenated hydrocarbon solvents. Among these organic solvents, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene and xylene are preferable.
Examples of the radical catalyst used in the above method include di-s-butylperoxydicarbonate, t-amylperoxypivalate, t-amylperoxy-2-ethylhexanoate, and azobisisobutyronitrile. Among these radical catalysts, azoisobutyronitrile is preferable.

  The unsaturated carboxylic acid-modified farnesene polymer obtained by the method (II) may be further reacted with a hydroxyl group-containing compound such as alcohol or an amino group-containing compound such as ammonia or amine. Unsaturated carboxylic acid ester-modified farnesene polymer, unsaturated carboxylic acid amide-modified farnesene polymer, or unsaturated by reacting an unsaturated carboxylic acid-modified farnesene polymer with a hydroxyl group-containing compound or amino group-containing compound A carboxylic acid imide-modified farnesene polymer can be obtained.

Examples of the hydroxyl group-containing compound to be reacted with the unsaturated carboxylic acid-modified farnesene polymer include hydroxyl group-containing (meth) acrylates in addition to alcohols such as methanol, ethanol and n-propanol. By using a hydroxyl group-containing (meth) acrylate, a (meth) acryloyl group-modified farnesene polymer can be obtained.
Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate, and among these, 2-hydroxyethyl ( (Meth) acrylate is preferred.

In the present invention, among the modified farnesene polymers that can be produced by the above-described method, modified farnesene polymers satisfying the following conditions (I) and (II) are used.
Condition (I): A modified farnesene polymer having a melt viscosity at 38 ° C. of 0.1 to 3,000 Pa · s.
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. Moreover, since the hardness of a crosslinked material becomes high, steering stability and rolling resistance performance, such as a tire using the crosslinked material, are improved.
From such a viewpoint, the melt viscosity at 38 ° C. of the modified farnesene polymer (C) of the present invention is more preferably 1.0 to 2,000 Pa · s, further preferably 2.5 to 1,500 Pa · s, 4.0 to 1,000 Pa · s is even more preferable. 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.

Condition (II): The maximum peak molecular weight (Mt) in gel permeation chromatography (GPC) is 3,000 to 550,000, and the total area derived from the polymer in the GPC chromatogram is 100%. A modified farnesene polymer having an area ratio of a polymer having a molecular weight of 45 or more of 0 to 20%.
The maximum peak molecular weight (Mt) of the modified farnesene polymer (C) is 3,000 to 550,000. When the Mt of the modified farnesene polymer (C) is within the above range, the processability of the rubber composition of the present invention will be good. Moreover, since the dispersibility of the filler in the obtained rubber composition is improved, for example, the rolling resistance performance of a tire made of the crosslinked product is improved. Further, the low migration performance is improved in the cross-linked product obtained from the rubber composition.
From such a viewpoint, the maximum peak molecular weight (Mt) of the modified farnesene polymer (C) is preferably 9,000 to 550,000, more preferably 15,000 to 450,000, and 30,000 to 300,000. Is more preferable. In the present invention, Mt of the modified farnesene polymer (C) is the maximum peak molecular weight in terms of polystyrene determined from the measurement of gel permeation chromatography (GPC).

In the modified farnesene polymer (C) in the present invention, the total area derived from the polymer in the GPC chromatogram obtained by the GPC measurement is 100%, and the area ratio of the polymer having a molecular weight of Mt × 1.45 or more is 0. ~ 20%.
When modification is performed by introducing a functional group into the unmodified farnesene polymer, the modification of the farnesene polymer and the double bond of the farnesene cause the polymer to bond to each other and increase in quantity. The body may generate. However, when the amount of the multimerized material in the rubber composition is large, adverse effects such as a decrease in filler dispersibility occur.
Therefore, in the present invention, the dispersibility of the filler can be improved by using a modified farnesene polymer with a low content of multimer, so that the mechanical strength, wear resistance, etc. of the crosslinked product are improved. Furthermore, rolling resistance performance of a tire or the like using the crosslinked product is improved. Furthermore, it becomes possible to make the crosslinked body high in hardness.
Although details of the reason why the above effect is obtained are not clear, when modifying an unmodified farnesene polymer, a by-product such as a polymer having a molecular weight of Mt × 1.45 or more, typically a coupling product, etc. It is presumed that the effect of the functional group introduced into the modified farnesene polymer becomes small when the multimer derived from the product exceeds the above ratio.

  From the viewpoint of improving the mechanical strength and hardness of the crosslinked product of the rubber composition and the rolling resistance performance of a tire or the like using the crosslinked product, the area ratio of the polymer having a molecular weight of Mt × 1.45 or more is 0 to 15. % Is preferable, and 0 to 10% is more preferable. In the present invention, the area ratio of the polymer in the region of Mt × 1.45 or more is the weight of the GPC chromatogram obtained by gel permeation chromatography (GPC) measurement under the conditions described in the examples described later. The total area derived from the coalescence (area surrounded by the GPC chromatogram and the baseline) is 100%, and is a value obtained from the area ratio of the polymer in the region.

The modified farnesene polymer (C) satisfying the above conditions (I) and (II) can be produced by the above-mentioned modified farnesene polymer production method, but a modifier is introduced as a more efficient production method. Examples thereof include a method of adding an antiaging agent in the reaction to be performed and a method of adjusting the temperature during the reaction. Among these, from the viewpoint of more efficient production, 0.1 to 100 parts by mass of the modifier and 0.01 to 10 parts by mass of the anti-aging agent with respect to 100 parts by mass of the polymer containing the monomer unit derived from farnesene. It is preferable to manufacture by the method of adding a part and making it react at 130 to 200 degreeC.
As the modifier, those exemplified as the modifier that can be used in the method (II) are preferable. Among these, from the viewpoint of economy and the like, one or more modifiers selected from unsaturated carboxylic anhydrides, unsaturated carboxylic acids and unsaturated carboxylic acid esters are preferable, and anhydrous unsaturated carboxylic acids are more preferable. As the unsaturated carboxylic anhydride, maleic anhydride is preferable from the viewpoint of sufficiently exerting the characteristics of the rubber composition and the crosslinked product comprising the rubber composition.

The addition amount of the modifier is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 30 parts by mass, with respect to 100 parts by mass of the polymer containing monomer units derived from farnesene. -20 mass parts is still more preferable.
Moreover, 0.01-8 mass parts is preferable with respect to 100 mass parts of polymers containing the monomer unit derived from farnesene, and, as for the addition amount of the said anti-aging agent, 0.1-3 mass parts is more preferable.
As reaction temperature, 140-180 degreeC is still more preferable.

  Examples of the antioxidant include 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) (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-butylphenyl) (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] dioxaphosphine-6 -Yloxy) propyl] -2-methylphenol (Sumilizer GP) (all of which are manufactured by Sumitomo Chemical Co., Ltd.), p-methoxyphenol, N-Fe Nyl-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-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), dioctadecyl 3,3'-dithiobispropionate, hydroquinone, etc. It is done. Moreover, the said anti-aging agent may use together 1 type (s) or 2 or more types.

  As another production method, after the production of the unmodified farnesene polymer, after sufficiently purifying and sufficiently removing the components that inhibit the reaction of introducing the modifier, the unmodified farnesene polymer and the modifier The method of making this react is mentioned. As a method for purifying the unmodified farnesene polymer, washing with water or warm water, an organic solvent such as methanol or acetone, or supercritical fluid carbon dioxide is preferable.

The modified farnesene polymer (C) of the present invention obtained by a modification reaction in which a modifying agent is introduced into an unmodified farnesene polymer is a modified modification introduced into the polymer with respect to the amount of the modifying agent used in the modification reaction. It is preferable that the modifier reaction rate that can be calculated as a proportion of the amount of the agent is 40 to 100%. The reaction is carried out so that the reaction rate of the modifier is within the above range, that is, the amount of the modifier so that the amount of the modifier remaining in the obtained modified farnesene polymer and the low molecular weight compound derived therefrom is reduced. By controlling the reaction, it is possible to further suppress adverse effects such as mold contamination derived from acidic components such as maleic anhydride due to the modifier and the low molecular weight compound derived therefrom.
The modifier reaction rate is more preferably 60 to 100%, still more preferably 70 to 100%, and still more preferably 80 to 100%.
For example, when one or more selected from unsaturated carboxylic anhydride, unsaturated carboxylic acid and unsaturated carboxylic acid ester is used as a modifier, the modifier reaction rate remains unpurified for the resulting modified farnesene polymer. It can be calculated by calculation from the measured acid value and the acid value measured for the modified farnesene polymer after purification.

  Examples of the method for producing the modified farnesene polymer (C) so as to satisfy the modifier reaction rate include a method in which the reaction for introducing the modifier is performed at an appropriate reaction temperature and for a sufficient reaction time. For example, the temperature of the reaction for adding maleic anhydride to the unmodified farnesene polymer is preferably 100 to 200 ° C, more preferably 130 to 200 ° C, and still more preferably 140 to 180 ° C. The reaction time is preferably 3 to 200 hours, more preferably 4 to 100 hours, and further preferably 5 to 50 hours.

Further, the amount of the modifying agent introduced into the modified farnesene polymer (C) is not particularly limited, but from the viewpoint of sufficiently exhibiting the characteristics of the obtained rubber composition and crosslinked product, the unmodified farnesene polymer 0.05-40 mass parts is preferable with respect to 100 mass parts, 0.1-30 mass parts is more preferable, and 0.1-20 mass parts is still more preferable.
When the amount of the introduced modifier is more than 40 parts by mass, the elongation of the obtained crosslinked product tends to decrease the tensile strength, and when it is less than 0.05 parts by mass, the abrasion resistance of the obtained crosslinked product, Rolling resistance performance and hardness tend to decrease.
The amount of modifier introduced into the modified farnesene polymer (C) can be calculated based on the modifier reaction rate of the modifier, and various analyzes such as infrared spectroscopy and nuclear magnetic resonance spectroscopy. It can also be determined using equipment.

The weight average molecular weight (Mw) of the modified farnesene polymer (C) is preferably 2,000 to 500,000, more preferably 8,000 to 500,000, still more preferably 15,000 to 450,000, and more preferably 30,000 to 300,000. Is even more preferable. When the Mw of the modified farnesene polymer (C) is within the above range, the processability of the rubber composition of the present invention is improved and the dispersibility of the filler in the resulting rubber composition is improved. The rolling resistance performance of a tire or the like using the tire becomes good.
In the present specification, Mw and Mn of the modified farnesene polymer (C) are a weight average molecular weight and a number average molecular weight in terms of polystyrene determined from measurement by gel permeation chromatography (GPC). In the present invention, two types of modified farnesene polymers having different Mw may be used in combination.

  The molecular weight distribution (Mw / Mn) of the modified farnesene polymer (C) 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 (C) is preferably -90 to 10 ° C, more preferably -90 to 0 ° C, still more preferably -90 to -5 ° C. When the glass transition temperature is in the above range, the rolling resistance performance is good. Moreover, it can suppress that a viscosity becomes high and can handle it easily. The vinyl content of the modified farnesene polymer is preferably 99% by mass or less, and more preferably 90% by mass or less.

In the rubber composition of the present invention, the content of the modified farnesene polymer (C) with respect to 100 parts by mass of the rubber component (A) is 0.1 to 30 parts by mass, preferably 0.5 to 30 parts by mass. -30 mass parts is more preferable, and 2-12 mass parts is still more preferable. When the content of the modified farnesene polymer (C) is within the above range, the mechanical strength and wear resistance of the crosslinked product of the rubber composition and the rolling resistance performance of a tire made of the crosslinked product are improved.
The modified farnesene polymer (C) used in the rubber composition of the present invention may contain two or more kinds of modified farnesene polymers (C) having different monomer units, molecular weights and functional groups. Good.

<Silane coupling agent>
When silica is used as the filler (B) 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; liquid polymer such as low molecular weight polybutadiene, low molecular weight polyisoprene, low molecular weight styrene butadiene copolymer, low molecular weight styrene isoprene copolymer; may contain unmodified farnesene polymer . 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 process oil, resin component, liquid polymer or unmodified farnesene polymer, the content is less than 50 parts by mass with respect to 100 parts by mass of the rubber component (A). It is preferable.

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, a brabender, a banbury mixer, an internal mixer, a single screw extruder, a twin screw extruder, a mixing roll, and a roller. Etc., and can usually be performed in a temperature range of 70 to 270 ° C.

[Crosslinked product comprising the rubber composition of the present invention]
The rubber composition of the present invention can be used after being crosslinked by adding a crosslinking agent. Examples of the crosslinking agent include sulfur, sulfur compounds, oxygen, organic peroxides, phenol resins and amino resins, quinones and quinone dioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides, and organic metals. Examples thereof include halides and silane compounds. These may be used alone or in combination of two or more. 0.1-10 mass parts is preferable with respect to 100 mass parts of rubber components (A), content of a crosslinking agent has more preferable 0.5-10 mass parts, and 0.8-5 mass parts is still more preferable.

  Among the above crosslinking agents, when sulfur and a sulfur compound are used, the rubber composition of the present invention can be vulcanized and used as a vulcanized rubber. Although there are no particular limitations on the vulcanization conditions and method, it is preferably carried out using a vulcanization mold under a pressure heating condition of 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 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, imidazolines. 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.

  The rubber composition of the present invention may further 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.

[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. In addition, you may use the crosslinked material which bridge | crosslinked the rubber composition of this invention for the tire of this invention. The tire using the rubber composition of the present invention or the crosslinked product of 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)>
Oil-extended styrene butadiene rubber: JSR1723 (manufactured by JSR Corporation) (A-1)
(Rubber component: 100 parts by mass, oil component: 37.5 parts by mass)
Styrene butadiene rubber: JSR1500 (manufactured by JSR Corporation) (A-2)

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

<Modified farnesene polymer>
Modified polyfarnesene (C-1), (C-2) and (X-1) manufactured according to the following Preparation Examples 1-3

<Optional component>
・ Sulfur (fine powder sulfur 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.)
・ Vulcanization accelerator Vulcanization accelerator (1): Noxeller CZ-G (manufactured by Ouchi Shinsei Chemical Co., Ltd.)
Vulcanization accelerator (2): Noxeller D (Ouchi Shinsei Chemical Co., Ltd.)
Vulcanization accelerator (3): 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.)

・ TDAE: VivaTec500 (manufactured by H & R)
・ Silane coupling agent: Si-75 (Evonik Degussa Japan)
・ Nocrack 6C (Ouchi Shinsei Chemical Co., Ltd.)
・ Wax: Suntite S (made by Seiko Chemical Co., Ltd.)

Production Example 1: Production of Modified Polyfarnesene (C-1) A sufficiently dried pressure vessel was replaced with nitrogen, and 1200 g of hexane and 5.0 g of n-butyllithium (17% by mass hexane solution) were charged into this pressure vessel, 50 After raising the temperature to 0 ° C., 1182 g of β-farnesene was added and polymerized for 1 hour while controlling the polymerization temperature to be 50 ° C. under stirring conditions. Thereafter, methanol was added to stop the polymerization reaction to obtain a polymerization solution (2388 g). Water was added to the obtained polymerization reaction liquid and stirred, and the polymerization reaction liquid was washed with water. Stirring was terminated, and after confirming that the polymerization solution phase and the aqueous phase were separated, water was separated. After completion of the washing, the polymerization reaction solution was dried at 70 ° C. for 12 hours to obtain unmodified polyfarnesene (C′-1).

Subsequently, 300 g of the obtained unmodified polyfarnesene (C′-1) was charged into an autoclave having a capacity of 1 liter subjected to nitrogen substitution, and 4.5 g of maleic anhydride and 2,6-di-t-butyl-4 were added. -3.0 g of methylphenol (BHT) was added and reacted at 160 ° C. for 20 hours to obtain maleic anhydride-modified polyfarnesene (C-1).
The modifier reaction rate was 88%, and the amount of the modifier introduced into the modified polyfarnesene (C-1) was 1.3 parts by mass with respect to 100 parts by mass of the unmodified polyfarnesene (C′-1). Table 1 shows the physical properties of the resulting modified polyfarnesene (C-1).

Production Example 2: Production of Modified Polyfarnesene (C-2) 300 g of unmodified polyfarnesene (C′-1) obtained in the same procedure as in Production Example 1 was charged into a 1 liter autoclave subjected to nitrogen substitution. Maleic anhydride 4.5 g and BHT 1.0 g were added and reacted at 160 ° C. for 20 hours to obtain maleic anhydride-modified polyfarnesene (C-2).
The modifier reaction rate was 88%, and the amount of the modifier introduced into the modified polyfarnesene (C-2) was 1.3 parts by mass with respect to 100 parts by mass of the unmodified polyfarnesene (C′-1). Table 1 shows the physical properties of the resulting modified polyfarnesene (C-2).

Production Example 3: Production of Modified Polyfarnesene (X-1) 300 g of unmodified polyfarnesene (C′-1) obtained in the same procedure as in Production Example 1 was charged into a 1-liter autoclave subjected to nitrogen substitution. Maleic anhydride 4.5g was added, and it was made to react at 160 degreeC for 20 hours, and the maleic anhydride modified polyfarnesene (X-1) was obtained.
The modifier reaction rate was 88%, and the amount of the modifier introduced into the modified polyfarnesene (X-1) was 1.3 parts by mass with respect to 100 parts by mass of the unmodified polyfarnesene (C′-1). Table 1 shows the physical properties of the obtained modified polyfarnesene (X-1).

In addition, the measuring method and calculation method of each physical property of a modified farnesene polymer are as follows.
(Measurement method of weight average molecular weight, maximum peak molecular weight and molecular weight distribution)
Mw, Mt, and Mw / Mn of the modified farnesene polymer 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
In addition, the ratio of the polymer having a molecular weight of Mt × 1.45 or more is obtained from the GPC chromatogram obtained by the GPC measurement under the above conditions to obtain the area of the polymer having a molecular weight of Mt × 1.45 or more. The total area derived from the polymer (the area surrounded by the GPC chromatogram and the base line) was determined as an area ratio when 100%.

(Measuring method of melt viscosity)
The melt viscosity of the modified farnesene polymer 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 was sampled on an aluminum pan, and a thermogram was measured by a differential scanning calorimetry (DSC) under a heating rate condition of 10 ° C./min. The peak top value of DDSC was taken as the glass transition temperature.

(Modifier reaction rate)
-Acid value of unpurified modified farnesene polymer (acid value before washing)
To 3 g of the sample after the denaturation reaction, 180 mL of toluene and 20 mL of ethanol were added and dissolved, and then neutralization titration with an ethanol solution of 0.1 N potassium hydroxide was performed to determine the acid value. For neutralization titration, phenolphthalein was used as an indicator.
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)
-Acid value of the modified farnesene polymer after purification (acid value after washing)
The sample after the denaturation reaction was washed 4 times with methanol (5 mL relative to 1 g of the sample) to remove unreacted maleic anhydride, and then the sample was dried under reduced pressure at 80 ° C. for 12 hours. The acid value was determined by the method. The modifier reaction rate was calculated based on the following formula.
[Modifier reaction rate] = [Acid value after washing] / [Acid value before washing] × 100

(Amount of modifier introduced into unmodified farnesene polymer)
From the modifier reaction rate determined above, the amount of the functional group introduced into the unreacted modified farnesene polymer was calculated according to the following formula.
[Amount of functional group derived from modifier introduced to 100 parts by mass of unmodified farnesene polymer] = [Mass of modifier added (g)] × [Modifier reaction rate (%)] / [Unmodified Mass of modified farnesene polymer (g)]

Examples 1-2 and Comparative Examples 1-2
According to the blending ratio (parts by mass) described in Table 2, rubber component (A), filler (B), modified farnesene polymer (C) or (X), TDAE, silane coupling agent, vulcanization aid, wax 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 placed in a mixing roll, sulfur and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain a rubber composition.
Further, the obtained rubber composition was press-molded (160 ° C., 35 to 40 minutes) to produce a crosslinked product (vulcanized rubber) sheet (thickness 2 mm). Based on the following methods, hardness and tensile strength at break The wear resistance and the rolling resistance performance were evaluated. The results are shown in Table 2.

In addition, the measuring method of each evaluation is as follows.
(1) Hardness Using the cross-linked sheets prepared in the 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. 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 larger the numerical value, the smaller the deformation of the tire when the composition is used for the tire, and the steering stability is improved.
(2) Tensile strength at break The dumbbell-shaped test piece was punched out from the cross-linked sheets prepared in Examples and Comparative Examples according to JIS3, and the tensile strength at break according to JIS K 6251 was measured using an Instron tensile tester. Was measured. 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, mechanical strength is so favorable that a numerical value is large.
(3) Abrasion resistance Based on JIS K 6264, the amount of DIN wear at a wear distance of 40 m was measured under a load of 10 N. The numerical values of each Example and Comparative Example in Table 2 are relative values when the value of Comparative Example 2 is set to 100 in the reciprocal of the DIN wear amount. The larger the numerical value, the smaller the amount of wear and the better the wear resistance.
(4) Rolling resistance performance A 40 mm long x 7 mm wide test piece was cut out from the cross-linked sheet produced in the examples and comparative examples, and measured using a dynamic viscoelasticity measuring device manufactured by GABO at a 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.

  From Table 2, the rubber compositions of Examples 1 and 2 that satisfy the constituent requirements of the present invention have higher hardness, mechanical strength, and resistance to resistance than the rubber composition of Comparative Example 2 that does not contain the modified farnesene polymer (C). It turns out that the crosslinked material which is excellent in both abrasion property and rolling resistance performance is obtained. In addition, the rubber compositions of Examples 1 and 2 that satisfy the constituent requirements of the present invention are comparative examples using the modified farnesene polymer (X-1) in which the proportion of the polymer having a molecular weight of Mt × 1.45 or more is too high. It can be seen that a cross-linked product having a high hardness and excellent mechanical strength, wear resistance, and rolling resistance performance can be obtained as compared with 1.

Examples 3-4 and Comparative Examples 3-4
A rubber composition was obtained in the same manner as in Example 1 except that each component was used according to the blending ratio (parts by mass) described in Table 3.
Further, the obtained rubber composition is press-molded (145 ° C., 25 to 30 minutes) to produce a cross-linked product (vulcanized rubber) sheet (thickness 2 mm). Based on the above-described methods, hardness and rolling resistance performance are obtained. Evaluated. The results are shown in Table 3. In addition, the numerical value of each Example about a hardness and a comparative example is a relative value when the value of the comparative example 4 is set to 100. Moreover, the numerical value of each Example and comparative example about rolling resistance performance is a relative value when the value of the comparative example 4 is set to 100.

  From Table 3, the rubber compositions of Examples 3 and 4 that satisfy the constituent requirements of the present invention use the modified farnesene polymer (X-1) in which the proportion of the polymer having a molecular weight of Mt × 1.45 or more is too high. It can be seen that a cross-linked product having high hardness and excellent rolling resistance performance can be obtained as compared with Comparative Example 3 described above. Moreover, it turns out that the rubber composition and crosslinked material which show these effects are obtained even if it changes the compounding quantity of a modified | denatured farnesene polymer (C).

  When the rubber composition of the present invention is made into a crosslinkable rubber composition by adding a crosslinking agent or the like, it is excellent in mechanical strength, wear resistance, etc., and gives a high hardness crosslinked product. It can be suitably used for industrial member applications such as industrial rubber hoses. In particular, when a crosslinked product is used for a tire application or the like, it is useful because the rolling resistance performance is improved.

Claims (14)

20 to 150 parts by mass of one or more fillers (B) selected from carbon black and silica with respect to 100 parts by mass of one or more rubber components (A) selected from synthetic rubber and natural rubber, and farnesene-derived A rubber composition containing 0.1 to 30 parts by mass of a modified farnesene polymer (C) containing a monomer unit, and the modified farnesene polymer (C) satisfies the following conditions (I) and (II): Rubber composition.
Condition (I): A modified farnesene polymer having a melt viscosity at 38 ° C. of 0.1 to 3,000 Pa · s.
Condition (II): The maximum peak molecular weight (Mt) in gel permeation chromatography (GPC) is 3,000 to 550,000, and the total area derived from the polymer in the GPC chromatogram is 100%. A modified farnesene polymer having an area ratio of a polymer having a molecular weight of 45 or more of 0 to 20%.   The rubber composition according to claim 1, wherein the modified farnesene polymer (C) has at least one functional group selected from a functional group derived from a carboxylic anhydride and an alkoxysilyl group.   The rubber composition according to claim 2, wherein the functional group derived from carboxylic anhydride is a functional group derived from maleic anhydride.   The rubber composition according to any one of claims 1 to 3, wherein the modified farnesene polymer (C) has a weight average molecular weight (Mw) of 2,000 to 500,000.   The modified farnesene polymer (C) is obtained by a modification reaction in which a modifier is introduced into the unmodified farnesene polymer, and is introduced into the polymer with respect to the amount of the modifier used in the modification reaction. The rubber composition according to any one of claims 1 to 4, wherein a modifier reaction rate that can be calculated as a ratio of the amount of the modified modifier is 40 to 100%.   The rubber composition according to any one of claims 1 to 5, 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 in any one of Claims 1-6 which contains 0.1-30 mass parts of silane coupling agents with respect to 100 mass parts of said silica.   The rubber composition according to any one of claims 1 to 7, wherein the rubber component is one or more selected from natural rubber, styrene butadiene rubber, butadiene rubber, and isoprene rubber.   The rubber composition according to claim 8, wherein the styrene-butadiene rubber has a weight average molecular weight of 100,000 to 2.5 million.   The rubber composition according to claim 8 or 9, wherein the styrene-butadiene rubber has a styrene content of 0.1 to 70 mass%.   The rubber composition according to any one of claims 8 to 10, wherein the butadiene rubber or isoprene rubber has a weight average molecular weight of 90,000 to 2,000,000.   The rubber composition according to any one of claims 8 to 11, wherein the vinyl content of the butadiene rubber or isoprene rubber is 50% by mass or less.   A tire using at least a part of the rubber composition according to claim 1.   To 100 parts by mass of a polymer containing a monomer unit derived from farnesene, 0.1 to 100 parts by mass of a modifier and 0.01 to 10 parts by mass of an antioxidant are added and reacted at 130 to 200 ° C. A method for producing a modified farnesene polymer.