JP2016089051A - Rubber composition and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition capable of manufacturing a crosslinked article excellent in processability and having enhanced mechanical strength, heat resistance and rolling resistance performance, and a tire using the composition at least partially.SOLUTION: There is provided a rubber composition comprising a solid rubber (A), at least one filler selected from carbon black and silica (B) and a polymer containing a monomer unit derived from farnesene and having catalyst residue amount derived from a metal catalyst used for manufacturing the polymer of 0 to 200 ppm in terms of metal, with the filler (B) content of 20 to 150 pts.mass and the polymer (C) content of 0.1 to 30 pts.mass based on 100 pts.mass of the solid rubber (A).SELECTED DRAWING: None

Description

  The present invention relates to a rubber composition including a polymer including a monomer unit derived from farnesene, and a tire using at least a part of a crosslinked product of the rubber composition.

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. In addition, since a rubber composition containing a filler has a high viscosity at the time of rubber kneading, rolling and extrusion, process oil or the like is used as a plasticizer for the purpose of improving processability and fluidity. Since such a plasticizer can soften the rubber composition after molding, it also has a function as a softener for the rubber composition.
However, in the above-mentioned tire use etc., there is a problem that the performance of rubber changes due to long-term use even if it has appropriate physical properties such as mechanical strength and hardness at the time of production. This occurs when a plasticizer or the like moves from the inside of the rubber to the outside.

As one method for suppressing such migration of plasticizers and the like, there is a method in which a liquid diene rubber is contained in the rubber composition in place of conventional plasticizers such as process oil. The rubber composition thus prepared and the crosslinked product comprising the rubber composition are excellent not only in processability but also in that the liquid diene rubber component is suppressed from being transferred after crosslinking. (For example, refer to Patent Document 1).
However, even when liquid diene rubber is contained in the rubber composition, the rubber composition has insufficient tack (adhesiveness), and it is difficult to mold and process the rubber compositions together. In some cases, molding workability deteriorated. Moreover, the cross-linked product obtained from the rubber composition may not always have sufficient physical properties such as heat resistance. Further, in a crosslinked product obtained from a rubber composition, particularly a tire, etc., further improvement in not only mechanical strength but also rolling resistance performance is desired.
Although Patent Documents 3 and 4 describe polymers of β-farnesene, practical applications have not been sufficiently studied.

JP 2008-120895 A International Publication No. 2010/027463 International Publication No. 2010/027464

  The present invention has been made in view of the above circumstances, and is a rubber composition capable of producing a crosslinked product having excellent processability and improved mechanical strength, heat resistance, and rolling resistance performance, and at least one of the composition. The tire used for the part is provided.

  As a result of intensive studies by the present inventors, by including a polymer containing a monomer unit derived from farnesene in the rubber composition, not only has excellent processability, but also a crosslinked product obtained from the rubber composition. Was found to be excellent in mechanical strength and the like, and improved in heat resistance and rolling resistance performance, and completed the present invention.

That is, the present invention relates to the following [1] and [2].
[1] A polymer comprising a solid rubber (A), at least one filler (B) selected from carbon black and silica, and a farnesene-derived monomer unit, the metal used for the production of the polymer It is a rubber composition containing the polymer (C) whose catalyst residue amount derived from the catalyst is 0 to 200 ppm in terms of metal, and 20 parts of the filler (B) with respect to 100 parts by mass of the solid rubber (A). A rubber composition containing 0.1 to 30 parts by mass of the polymer (C).
[2] A tire using at least a part of the rubber composition according to [1].

  According to the present invention, it is possible to obtain a rubber composition that not only has excellent processability but also has excellent mechanical strength when cross-linked and improved heat resistance and rolling resistance performance. Therefore, the rubber composition and a crosslinked product of the composition are useful, for example, as at least a part of a tire, and a tire using the rubber composition is excellent in the various performances described above.

[Solid rubber (A)]
The solid rubber (A) used in the rubber composition of the present invention refers to a rubber that can be handled in a solid state. The Mooney viscosity ML _{1 + 4} at 100 ° C. of the solid rubber (A) is usually in the range of 20 to 200. Examples of the solid rubber (A) include natural rubber, styrene butadiene rubber (hereinafter also referred to as “SBR”), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, and butadiene acrylonitrile copolymer. Examples thereof include rubber, chloroprene rubber, acrylic rubber, fluorine rubber, and urethane rubber. Among these solid rubbers (A), natural rubber, SBR, butadiene rubber, and isoprene rubber are preferable, and natural rubber and SBR are more preferable. These solid rubbers (A) may be used alone or in combination of two or more.

  The number average molecular weight (Mn) of the solid rubber (A) is preferably 80,000 or more from the viewpoint of sufficiently exhibiting the characteristics of the obtained rubber composition and crosslinked product, and is 100,000 to 3,000,000. More preferably within the range of 000. In addition, the number average molecular weight in this specification is the number average molecular weight of polystyrene conversion calculated | required from the measurement of gel permeation chromatography (GPC).

  Examples of the natural rubber include natural rubber, high-purity natural rubber, epoxidized natural rubber, hydroxylated natural rubber, hydrogenated natural rubber commonly used in the tire industry such as TSR and RSS such as SMR, SIR, and STR. Examples thereof include modified natural rubber such as grafted natural rubber. Among these, SMR20, STR20, and RSS # 3 are preferable from the viewpoint of little variation in quality and easy availability. These natural rubbers may be used alone or in combination of two or more.

  As the SBR, a general one used for a tire can be used. Specifically, a styrene content of 0.1 to 70% by mass is preferable, a 5 to 50% by mass is more preferable, and 15 to 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 still 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, the weight average molecular weight in this specification is the weight average molecular weight of polystyrene conversion calculated | required from the measurement of gel permeation chromatography (GPC).

  The glass transition temperature determined by the differential thermal analysis method of SBR used in the present invention is preferably −95 to 0 ° C., more preferably −95 to −5 ° C. By setting the glass transition temperature in the above range, it is possible to suppress an increase in viscosity and to facilitate handling.

  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, Any of an emulsion polymerization method, a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method may be sufficient. Of these, emulsion polymerization and solution polymerization are preferred.

Emulsion-polymerized styrene-butadiene rubber (hereinafter also referred to as “E-SBR”) can be produced by an ordinary emulsion polymerization method. For example, a predetermined amount of styrene and a butadiene monomer are emulsified and dispersed in the presence of an emulsifier, and radical polymerization is performed. It can be obtained by emulsion polymerization with an 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 0-60 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 termination of the polymerization reaction, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride or potassium chloride is used as a coagulant, and an acid such as nitric acid or sulfuric acid as necessary. Is added to adjust the pH of the coagulation system to a predetermined value, the polymer is coagulated, and then the polymer can be recovered as crumb by 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.

A solution-polymerized styrene butadiene rubber (hereinafter also referred to as “S-SBR”) can be produced by an ordinary solution polymerization method. For example, an active metal capable of anionic polymerization in a solvent is used, and optionally in the presence of a polar compound. Polymerize styrene and butadiene.
Examples of the active metal capable of anion polymerization 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 toluene Aromatic hydrocarbons and the like. These solvents are usually 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 organolithium 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 moiety and the distribution of styrene in the copolymer chain without deactivating the reaction in anionic polymerization. For example, dibutyl ether And ether compounds such as 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. Before removing the solvent,
The polymerization solution and the extending oil may be mixed in advance and recovered as an oil-extended rubber.

As the SBR, a modified SBR in which a functional group is introduced into the SBR may be used. Examples of the functional group include an amino group, an alkoxysilyl group, a hydroxyl 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, 3 which can react with the polymerization active terminal are used. -Coupling agents such as aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, 4,4'-bis (diethylamino) benzophenone, N-vinylpyrrolidone, etc. Examples thereof include a method of adding a polymerization terminal modifier or other modifiers described in JP2011-132298A.
In this modified SBR, the position at which the functional group is introduced may be the polymer end or the side chain of the polymer chain.

  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.
The butadiene rubber is partially branched by using 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 structure or a polar functional group.

  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 using a lanthanoid rare earth metal catalyst such as an organic acid neodymium-Lewis acid or the like, 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 partially branched by using 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 structure or a polar functional group.

[Filler (B)]
The filler (B) used in the rubber composition of the present invention is at least one filler selected from carbon black and silica, and is blended for the purpose of improving physical properties such as improving mechanical strength.

Examples of the carbon black include furnace black, channel black, thermal black, acetylene black, and ketjen black. Of these, furnace black is preferable from the viewpoint of improving the crosslinking speed and mechanical strength. 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, hardness, and the like.
Examples of commercial products of the 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, dispersibility, etc. to the solid rubber (A), the carbon black is subjected to acid treatment with nitric acid, sulfuric acid, hydrochloric acid or a mixed acid thereof, or surface oxidation treatment by heat treatment in the presence of air. 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 and crosslinked material of this invention. As the graphitization catalyst, boron, boron oxide (for example, B ₂ O ₂ , B ₂ O ₃ , B ₄ O ₃ , B ₄ O _5, etc.), boron oxo acid (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 carbon black can also be used after adjusting the particle size 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.

Examples of the 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 processability, mechanical strength, and wear resistance. These silicas may be used alone or in combination of two or more.
The average particle diameter of silica is preferably 0.5 to 200 nm, more preferably 5 to 150 nm, and still more preferably 10 to 100 nm from the viewpoint of improving processability, rolling resistance performance, mechanical strength, and wear resistance.
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.

In the rubber composition of the present invention, the content of the filler (B) with respect to 100 parts by mass of the solid rubber (A) is 20 to 150 parts by mass, preferably 25 to 130 parts by mass, and more preferably 25 to 110 parts by mass. preferable. When the content of the filler (B) is within the above range, workability, rolling resistance performance, mechanical strength and wear resistance are improved.
A filler (B) may be used individually by 1 type, and may use 2 or more types together. Among these fillers (B), it is more preferable to use carbon black from the viewpoint of the reinforcing properties of the resulting rubber composition and its crosslinked product.

[Polymer (C)]
The polymer (C) used in the rubber composition of the present invention is a polymer containing monomer units derived from farnesene, and the amount of catalyst residue derived from the metal catalyst used in the production of the polymer is 0 in terms of metal. It is a polymer characterized by a content of ˜200 ppm (hereinafter also referred to as “farnesene polymer (C)”).

  The farnesene polymer (C) is preferably a polymer obtained by polymerizing farnesene by the method described below. In the rubber composition of the present invention, the farnesene polymer (C) acts as a plasticizer. In the crosslinked product of the rubber composition, the farnesene polymer (C) can be used to migrate from the inside of the crosslinked product to the outside. Is low, and the crosslinked product which shows the outstanding low migration performance can be obtained.

  As the farnesene constituting the farnesene polymer (C) in the present invention, at least one selected from α-farnesene and β-farnesene represented by the formula (I) can be used. -It is preferred to use farnesene.

The farnesene polymer (C) may be composed only of monomer units derived from farnesene, or composed of monomer units derived from farnesene and monomer units derived from monomers other than farnesene. Also good.
When the farnesene polymer (C) 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-phenyl-butadiene, 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.

  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 processability of the resulting rubber composition. From the viewpoint of improving rolling resistance performance of a tire or the like using a crosslinked product of the rubber composition, 1 to 99% by mass is preferable, 10 to 80% by mass is more preferable, and 15 to 70% by mass is further preferable.

(Method for producing farnesene polymer (C))
The farnesene polymer (C) can be produced, for example, by a solution polymerization method.
As the solution polymerization method, a known method or a method according to a known method can be applied. For example, a monomer containing farnesene in a solvent and using a metal catalyst such as a Ziegler catalyst, a metallocene catalyst, an anionically polymerizable active metal or an active metal compound, if necessary, in the presence of a polar compound Is polymerized.
Examples of the active metal capable of anion polymerization 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.

As the active metal compound capable of anionic polymerization, an organic alkali metal compound is preferable.
Examples of the organic alkali metal compound include organic monolithium compounds such as methyl lithium, ethyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium, hexyl lithium, phenyl lithium and stilbene lithium; Polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Of these, organolithium compounds are preferred.
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 amount of the organic alkali metal compound used can be appropriately set according to the melt viscosity, molecular weight, etc. of the farnesene polymer (C), but is usually 0.01 to 3 masses per 100 mass parts of the total monomer containing farnesene. Used in part quantities.

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 can be used.
In the anionic polymerization, the polar compound is usually used to adjust the microstructure of the conjugated diene site without deactivating the reaction. Examples of polar compounds 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 polar compound is usually used in an amount of 0.01 to 1000 mol with respect to the metal catalyst.

  The temperature of solution polymerization is usually in the range of -80 to 150 ° C, preferably in the range of 0 to 100 ° C, more preferably in the range of 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 obtained polymerization reaction liquid is poured into a poor solvent such as methanol to precipitate the farnesene polymer (C), or the polymerization reaction liquid is washed with water, separated, and dried to obtain a simple farnesene polymer (C). Can be separated.

The farnesene polymer (C) may be a modified farnesene polymer modified with various functional groups. Examples of functional groups include amino groups, amide groups, imino groups, imidazole groups, urea groups, alkoxysilyl groups, hydroxyl groups, epoxy groups, ether groups, carboxyl groups, carbonyl groups, mercapto groups, isocyanate groups, nitrile groups, and acid anhydrides. Examples include physical groups.
As a method for producing a modified farnesene polymer, for example, before adding a polymerization terminator, tin tetrachloride, dibutyltin chloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxy, which can react with a polymerization active terminal, can be used. Coupling agents such as silane, tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, and 4,4′-bis (diethylamino) benzophenone , N-vinylpyrrolidone, N-methylpyrrolidone, 4-dimethylaminobenzylideneaniline, dimethylimidazolidinone or other modified compounds described in JP2011-132298A are added and unmodified Farnesene heavy The method of adding to a coalescence is mentioned.
In addition, a modified farnesene polymer can be produced by graft-reacting maleic anhydride or the like to the unmodified farnesene polymer (C) after isolation.
In this modified farnesene polymer, the position at which the functional group is introduced may be the polymer end or the side chain of the polymer chain. Moreover, the said functional group can also be used combining 1 type (s) or 2 or more types. The above modifier is preferably used in the range of 0.01 to 100 molar equivalents relative to the metal catalyst.

  The farnesene polymer (C) is characterized in that the amount of catalyst residue derived from the metal catalyst used for the production thereof is in the range of 0 to 200 ppm in terms of metal. For example, when an organic alkali metal such as an organolithium compound is used as the metal catalyst for producing the farnesene polymer (C), the metal serving as a reference for the catalyst residue amount is an alkali metal such as lithium. When the amount of catalyst residue is in the above range, tack does not decrease during processing, etc., the heat resistance of the crosslinked product of the rubber composition of the present invention is improved, and the rolling resistance performance of a tire made of the crosslinked product is improved. improves. The amount of catalyst residue derived from the metal catalyst used in the production of the farnesene polymer (C) is preferably 0 to 150 ppm, more preferably 0 to 100 ppm in terms of metal. The amount of catalyst residue can be measured by using, for example, a polarized Zeeman atomic absorption spectrophotometer.

  Examples of the method of setting the amount of catalyst residue of the farnesene polymer (C) to such a specific amount include a method of purifying the farnesene polymer (C) after polymerization and sufficiently removing the catalyst residue. As a purification method, washing with water or warm water, an organic solvent typified by methanol, acetone or the like, or supercritical fluid carbon dioxide is preferable. The number of washings is preferably 1 to 20 times and more preferably 1 to 10 times from an economical viewpoint. The washing temperature is preferably 20 to 100 ° C, more preferably 40 to 90 ° C. In addition, the amount of metal catalyst required to obtain a specific molecular weight is reduced by removing impurities that inhibit polymerization by distillation or adsorbent before the polymerization reaction, and performing polymerization after increasing the purity. Therefore, the amount of catalyst residue can be reduced.

  The melt viscosity of the farnesene polymer (C) measured at 38 ° C. is preferably in the range of 0.1 to 3,000 Pa · s, more preferably in the range of 1.0 to 2,000 Pa · s, and 2.5 to 1 , 500 Pa · s is more preferable, and a range of 4.0 to 1,000 Pa · s is even more preferable. When the melt viscosity of the farnesene polymer (C) is within the above range, kneading of the resulting rubber composition is facilitated and processability is improved. Furthermore, the low migration performance and rolling resistance performance of the crosslinked product of the rubber composition are also improved. In addition, in this invention, the melt viscosity of a farnesene polymer (C) is the value calculated | required by the method described in the Example mentioned later.

The weight average molecular weight (Mw) of the farnesene polymer (C) is preferably from 2,000 to 500,000, more preferably from 8,000 to 500,000, still more preferably from 15,000 to 450,000, and from 30,000 to 300,000. Even more preferred. When the Mw of the 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 (B) in the obtained rubber composition is improved. For example, the rolling resistance performance of a tire made of the crosslinked product becomes good. In addition, the low migration performance is improved in the cross-linked product obtained from the rubber composition.
In the present invention, two or more kinds of farnesene polymers (C) having different Mw may be used in combination.

  The molecular weight distribution (Mw / Mn) of the 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. When Mw / Mn is within the above range, the variation in viscosity is small and more preferable.

  The glass transition temperature (Tg) of the farnesene polymer (C) can vary depending on the vinyl content of the farnesene monomer units, the content of units derived from monomers other than farnesene, etc., but is preferably -90 to 10 ° C. -90-0 degreeC is more preferable, and -90--5 degreeC is still more preferable. When the Tg is in the above range, for example, the rolling resistance performance of a tire made of a crosslinked product of the rubber composition becomes good. Moreover, it can suppress that a viscosity becomes high and can handle it easily. The vinyl content of the farnesene polymer (C) 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 farnesene polymer (C) with respect to 100 parts by mass of the solid rubber (A) is 0.1 to 30 parts by mass, preferably 0.5 to 30 parts by mass, and 1 to 30 parts. A mass part is more preferable and 2-20 mass parts is still more preferable. When the content of the farnesene polymer (C) is within the above range, the processability of the rubber composition, the mechanical strength of the crosslinked product of the rubber composition, the low migration performance, and the rolling resistance performance of a tire made of the crosslinked product, etc. Becomes better.
The farnesene polymer (C) used in the present invention may be a mixture of two or more types of farnesene polymers having different monomer units, molecular weights and functional groups.

  In the rubber composition of the present invention, the amount of the catalyst residue derived from the polymer (C) contained in the rubber composition is preferably 0 to 40 ppm, more preferably 0 to 20 ppm, and more preferably 0 to 10 ppm in terms of metal. More preferred is 0 to 5 ppm. When the amount of catalyst residue is in the above range, tack does not decrease during processing, etc., the heat resistance of the crosslinked product of the rubber composition of the present invention is improved, and the rolling resistance performance of a tire made of the crosslinked product is improved. improves.

[Other ingredients]
The rubber composition of the present invention may further contain a crosslinking agent in order to crosslink the rubber. Examples of the crosslinking agent (D) include sulfur, sulfur compounds, oxygen, organic peroxides, phenol resins, amino resins, quinone and quinone dioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides. And organic metal halides and silane compounds. Examples of the sulfur compound include morpholine disulfide and alkylphenol disulfide. Organic peroxides include cyclohexanone peroxide, methyl acetoacetate peroxide, tert-butyl peroxyisobutyrate, tert-butyl peroxybenzoate, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-tert-butyl Examples thereof include peroxide and 1,3-bis (tert-butylperoxyisopropyl) benzene. These crosslinking agents (D) may be used individually by 1 type, and may use 2 or more types together. The crosslinking agent (D) is usually 0.1 to 10 parts by mass, preferably 0.5 to 10 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the solid rubber (A) from the viewpoint of mechanical properties of the crosslinked product. 0.8 to 5 parts by mass is contained.

  The rubber composition of the present invention further contains a vulcanization accelerator (E) when sulfur, a sulfur compound, etc. are contained as a crosslinking agent (D) for crosslinking (vulcanizing) rubber, for example. May be. Examples of the vulcanization accelerator (E) include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds, aldehyde-ammonia compounds, Examples include imidazoline compounds and xanthate compounds. These vulcanization accelerators (E) may be used alone or in combination of two or more. The said vulcanization accelerator (E) is 0.1-15 mass parts normally with respect to 100 mass parts of solid rubber (A), Preferably 0.1-10 mass parts is contained.

  The rubber composition of the present invention further contains a vulcanization aid (F) when sulfur, a sulfur compound, etc. are contained as a crosslinking agent (D) for crosslinking (vulcanizing) rubber, for example. Also good. Examples of the vulcanization aid (F) include fatty acids such as stearic acid, metal oxides such as zinc white, and fatty acid metal salts such as zinc stearate. These vulcanization aids (F) may be used alone or in combination of two or more. The said vulcanization | cure adjuvant (F) is 0.1-15 mass parts normally with respect to 100 mass parts of solid rubber (A), Preferably 1-10 mass parts is contained.

In the rubber composition of this invention, when a silica is contained as a filler (B), it is one preferable aspect 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-trimethoxysilyl). Ethyl) 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, N Dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide It is done.
Examples of mercapto compounds include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane.
Examples of vinyl compounds 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, γ-glycidoxypropylmethyldimethoxysilane, and the like. It is done.
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. Among these, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) tetrasulfide, and 3-mercaptopropyltrimethoxysilane are preferable from the viewpoint of a large addition effect and cost.
Preferably the said silane coupling agent is 0.1-30 mass parts with respect to 100 mass parts of silica, More preferably, it is 0.5-20 mass parts, More preferably, 1-15 mass parts is contained. When the content of the silane coupling agent is within the above range, dispersibility, coupling effect, reinforcing property, and wear resistance are improved.

  The rubber composition of the present invention has the purpose of improving physical properties such as mechanical strength, heat resistance, or weather resistance, adjusting the hardness, increasing the amount of rubber, etc., as long as the effects of the present invention are not impaired. A filler (B ′) other than B) may be contained. Examples of the filler (B ′) include clay, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, titanium oxide, glass fiber, fibrous filler, inorganic filler such as glass balloon, resin particles, wood powder, And organic fillers such as cork powder. When the rubber composition of this invention contains the said filler (B '), 0.1-120 mass parts is preferable with respect to 100 mass parts of rubber components (A), 5-90 mass parts is preferable. Is more preferable, and 10-80 mass parts is still more preferable.

  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 A resin component such as a resin may be contained as a softening agent. When the rubber composition of the present invention contains the process oil as a softening agent, the content is preferably less than 50 parts by mass with respect to 100 parts by mass of the solid rubber (A).

  The rubber composition of the present invention is an anti-aging agent, a wax, an antioxidant, a lubricant, if necessary for the purpose of improving weather resistance, heat resistance, oxidation resistance, etc., as long as the effects of the present invention are not impaired. Light 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, and antibacterial agents You may contain additives, such as a mold agent and a fragrance | flavor. 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. These additives may be used alone or in combination of two or more.

[Method for producing rubber composition]
The manufacturing method of the rubber composition of this invention will not be specifically limited if said each component can be mixed uniformly. As an apparatus used for manufacturing the rubber composition, for example, a tangential or meshing type closed kneader such as a kneader ruder, Brabender, Banbury mixer, internal mixer, a single screw extruder, a twin screw extruder, a mixing roll, And rollers. The rubber composition can be usually produced in a temperature range of 70 to 270 ° C.

[Crosslinked product]
A crosslinked product can be obtained by crosslinking the rubber composition of the present invention. The crosslinking conditions of the rubber composition can be appropriately set according to the use and the like. For example, when sulfur or a sulfur compound is used as a crosslinking agent and the rubber composition is crosslinked (vulcanized) with a mold, the crosslinking temperature is usually 120 to 200 ° C., and the pressure condition is usually 0.5 to 2.0 MPa. It can be crosslinked (vulcanized).

The extraction rate of the farnesene polymer (C) from the crosslinked product is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less.
The extraction rate can be calculated from the amount of the polymer (B) extracted by immersing 2 g of the cross-linked product in 400 ml of toluene and 48 hours at 23 ° C.

[tire]
The tire of the present invention (including a pneumatic tire, the same applies hereinafter) uses the rubber composition of the present invention at least in part. Therefore, the mechanical strength is good and it has excellent rolling resistance performance. The rubber composition of the present invention can be suitably used for a tread portion, a sidewall portion, a bead filler portion, a rim cushion portion, a shoulder portion and the like of a tire. In particular, when used in a cap tread portion and / or a base tread portion in a tread portion, low fuel consumption performance can be effectively exhibited due to the excellent rolling resistance performance. Moreover, since the tire using the crosslinked product of the rubber composition of the present invention has a low transferability of the farnesene polymer (C) or the like, the characteristics such as the mechanical strength can be maintained even when used for a long time.
The tire of the present invention can be used as an all-season tire, a summer tire, a snow tire, a studless tire, etc. for passenger cars and large vehicles such as trucks, buses and construction vehicles.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Each component used in the examples and comparative examples is as follows.
・ Solid rubber (A)
Natural rubber: “SMR20” (natural rubber made in Malaysia)
・ Filler (B)
Carbon black: Diamond Black I (Mitsubishi Chemical Corporation, average particle size 20 nm)
-Farnesene polymer (C)
Polyfarnesene / farnesene polymer (C ′) of Production Examples 1 to 4 described later
Polyfarnesene of Production Examples 5 and 6 to be described later

・ Crosslinking agent (D)
Sulfur (fine sulfur 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.)
・ Vulcanization accelerator (E)
Noxeller NS-P (Ouchi Shinsei Chemical Co., Ltd.)
・ Vulcanizing aid (F)
Stearic acid: LUNAC S-20 (manufactured by Kao Corporation)
・ Others Zinc flower: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.)
TDAE: VivaTec500 (manufactured by H & R)
Anti-aging agent (1): NOCRACK 6C (manufactured by Ouchi Shinsei Chemical Co., Ltd.)
Anti-aging agent (2): ANTAGE RD (Kawaguchi Chemical Industry Co., Ltd.)

Production Example 1: Production of 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, and the temperature was adjusted to 50 ° C. After the temperature was raised, 1182 g of farnesene was added and the polymerization was carried out 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 2388 g of a polymerization solution. To this polymerization solution in a pressure vessel, warm water at 60 ° C. was added so that the volume ratio of polymerization solution / warm water = 2/1, stirred for 30 minutes, and allowed to stand for 30 minutes. After confirming that they were separated, the aqueous phase was removed (hereinafter, this operation is referred to as a washing operation (1)). This washing operation (1) was further repeated, and the washing operation (1) was performed 7 times in total. The polymer solution that had undergone the washing operation was vacuum-dried for 12 hours to obtain polyfarnesene (C-1). Table 1 shows the physical properties of the obtained polyfarnesene (C-1).

Production Example 2: Production of polyfarnesene (C-2) A liquid polyfarnesene (C-2) was obtained by performing the same polymerization, washing operation and drying as in Production Example 1 except that the washing operation (1) was performed twice. It was. Table 1 shows the physical properties of the obtained liquid polyfarnesene (C-2).

Production Example 3: Production of polyfarnesene (C-3) A sufficiently dried pressure vessel was replaced with nitrogen, and 1216 g of cyclohexane and 42.6 g of sec-butyllithium (10.5 mass% cyclohexane solution) were charged into this pressure vessel. After the temperature was raised to 0 ° C., 1880 g of farnesene was added and polymerization was conducted for 1 hour under stirring conditions while controlling the polymerization temperature to be 50 ° C. Thereafter, methanol was added to stop the polymerization reaction to obtain 3141 g of a polymerization solution. Thereafter, the washing operation (1) described in Production Example 1 was performed 10 times. The polymer solution that had undergone the washing operation was vacuum-dried for 12 hours to obtain polyfarnesene (C-3). Table 1 shows the physical properties of the obtained polyfarnesene (C-3).

Production Example 4: Production of polyfarnesene (C-4) Liquid polyfarnesene (C-4) was obtained by performing the same polymerization, washing operation and drying as in Production Example 3 except that the washing operation (1) was repeated 5 times. It was. Table 1 shows the physical properties of the obtained liquid polyfarnesene (C-4).

Production Example 5: Production of polyfarnesene (C′-1) Polymerization was carried out in the same manner as in Production Example 1, and methanol was added to the polymerization reaction solution to stop the polymerization reaction. Next, after removing the polymerization solution from the pressure-resistant container, the pressure-resistant container was continuously used without washing, and 287 g of farnesene was charged, and the second polymerization was performed in the same polymerization step as in Production Example 1. The obtained polymerization solution was vacuum-dried at 70 ° C. for 12 hours without washing to obtain polyfarnesene (C′-1). Table 1 shows the physical properties of the obtained liquid polyfarnesene (C′-1).

Production Example 6: Production of polyfarnesene (C′-2) Polymerization was carried out in the same manner as in Production Example 3, and methanol was added to the polymerization reaction solution to stop the polymerization reaction. Next, after removing the polymerization solution from the pressure-resistant container, the pressure-resistant container was continuously used without washing, 1012 g of farnesene was charged, and the second polymerization was performed in the same polymerization step as in Production Example 3. The obtained polymerization solution was vacuum-dried at 70 ° C. for 12 hours without washing to obtain polyfarnesene (C′-2). Table 1 shows the physical properties of the obtained liquid polyfarnesene (C′-2).

In addition, the measuring methods of the weight average molecular weight (Mw), melt viscosity, and catalyst residue amount of farnesene polymers (C) and (C ′) are as follows.
(Measurement method of weight average molecular weight)
Mw of the farnesene polymers (C) and (C ′) was determined by GPC (gel permeation chromatography) as a 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 at 38 ° C. of the farnesene polymers (C) and (C ′) was measured with a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

(Amount of catalyst residue)
1) Preparation of sample solution, etc. Sample solution: The farnesene polymers (C) and (C ′) obtained in Production Examples 1 to 6 were accurately weighed and pretreated with a small amount of concentrated sulfuric acid. After that, it was put into a platinum dish and gradually heated with an electric stove to be ashed. After cooling, 5 mL of 20% (v / v) hydrochloric acid was added, and ultrapure water was further added to make 50 mL, which was used as a sample solution.

Standard solution (a) (blank): Ultrapure water was added to 5 mL of 20% (v / v) hydrochloric acid to make 50 mL.
Standard solution (b) (Li: 0.1 ppm (w / v)): 20 mL (v / v) hydrochloric acid 5 mL and lithium standard solution (1000 ppm (w / v)) 0.005 mL were accurately taken, and ultrapure water was added. Add to 50 mL.
Standard solution (c) (Li: 2.0 ppm (w / v)): 20 mL (v / v) hydrochloric acid 5 mL and lithium standard solution (1000 ppm (w / v)) 0.10 mL were accurately taken, and ultrapure water was added. Add to 50 mL.
Standard solution (d) (Li: 5.0 ppm (w / v)): 20% (v / v) hydrochloric acid 5 mL and lithium standard solution (1000 ppm (w / v)) 0.25 mL were accurately taken, and ultrapure water was added. Add to 50 mL.

2) Measuring method It was determined by a calibration curve method using an atomic absorption photometric flame method (frame: air-acetylene (wavelength: 670.8 nm)). The absorbance is measured in the order of the standard solutions (a), (b), (c) and (d), and a calibration curve is prepared. Next, the absorbance of the sample solution was measured, and the amount of lithium catalyst residue per 1 g of farnesene polymer (C) was calculated according to the following formula. A polarization Zeeman atomic absorption spectrophotometer (model “Z-5010”, manufactured by Hitachi High-Technologies Corporation) was used for the measurement of absorbance. A product manufactured by Wako Pure Chemical Industries, Ltd. was used as the lithium standard solution for atomic absorption.
Catalyst residue amount (lithium: ppm (w / v)) = (C / sampled amount (g)) × 50
(However, C = Lithium concentration in the measuring solution (ppm (w / v)))

(Examples 1-2 and Comparative Examples 1-2)
Solid rubber (A), filler (B), farnesene polymer (C), farnesene polymer (C ′), TDAE, crosslinking aid (F) and aging according to the blending ratio (parts by mass) described in Table 2 The inhibitors 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., and then taken out of the mixer and cooled to room temperature. Subsequently, this mixture was put into a mixing roll, a crosslinking agent (D) and a crosslinking accelerator (E) were added, and kneaded at 60 ° C. for 6 minutes to obtain a rubber composition. The tack of the obtained rubber composition was measured by the following method.
Further, the obtained rubber composition is press-molded (145 ° C., 25 minutes) to produce a crosslinked product (vulcanized rubber) sheet (thickness 2 mm), and after rolling resistance performance and thermal deterioration based on the following methods Tensile strength retention was evaluated. The results are shown in Table 2.
In addition, the measuring method of each evaluation is as follows.
(1) Tack Unvulcanized rubber compositions prepared in Examples and Comparative Examples were formed into a sheet having a thickness of 2 mm using a roll, and two 4 cm × 2.5 cm test pieces were cut out. In an environment of 23 ± 2 ° C. and relative humidity of 65 ± 15%, the test pieces are bonded to each other for 10 seconds under a load of 100 g / cm ² , and the adhesive strength (tack) when the test pieces are peeled off in three stages. evaluated. When the tack of the rubber composition of Comparative Example 2 is 2, the tack is stronger than the rubber composition of Comparative Example 2, 3 when the tack is equivalent to the rubber composition of Comparative Example 2, and the tack is weaker than that. The case was 1. When the value is 2, the tack is good.
(2) Rolling resistance performance A 40 mm long x 7 mm wide test piece 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 temperature of 60 ° C and a frequency. Tan δ was measured under the conditions of 10 Hz, static strain 10%, and dynamic strain 2%, 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.
(3) Tensile strength retention after heat aging (%)
The rubber composition sheets prepared in the examples and comparative examples were heated at 100 ° C. for 48 hours to be thermally aged, and then a dumbbell-shaped test piece was punched out according to JIS3, and a JIS-made tensile tester was used. The tensile strength at break was measured according to K6251. In addition, the tensile strength at break was measured in the same manner for the sheet not thermally deteriorated. Based on the following formula, the tensile strength retention after heat aging was calculated. Note that the closer the value is to 100, the smaller the change in physical properties after heat deterioration and the better the heat resistance.
[Tensile strength retention after thermal degradation (%)] = [Tensile fracture strength after thermal degradation] / [Tensile fracture strength before thermal degradation] × 100

  From Examples 1-2 and Comparative Example 2, it can be seen that a rubber composition excellent in rolling resistance performance can be obtained by using a farnesene polymer having a specific catalyst residue amount. From Examples 1-2 and Comparative Example 1, by using a farnesene polymer in which the amount of catalyst residue is within the range of the present invention, rubber having good tack and excellent workability, and having both rolling resistance performance and heat resistance It can be seen that a composition is obtained.

(Examples 3-4 and Comparative Examples 3-4)
Solid rubber (A), filler (B), farnesene polymer (C), farnesene polymer (C ′), TDAE, crosslinking aid (F) and aging according to the blending ratio (parts by mass) described in Table 3 The inhibitors 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., and then taken out of the mixer and cooled to room temperature. Subsequently, this mixture was put into a mixing roll, a crosslinking agent (D) and a crosslinking accelerator (E) were added, and kneaded at 60 ° C. for 6 minutes to obtain a rubber composition. The tack of the obtained rubber composition was measured by the following method.
Further, the obtained rubber composition is press-molded (145 ° C., 25 minutes) to produce a crosslinked product (vulcanized rubber) sheet (thickness 2 mm), and after rolling resistance performance and thermal deterioration based on the following methods Tensile strength retention was evaluated. The results are shown in Table 3.
In addition, the measuring method of each evaluation is as follows.
(1) Tack Unvulcanized rubber compositions prepared in Examples and Comparative Examples were formed into a sheet having a thickness of 2 mm using a roll, and two 4 cm × 2.5 cm test pieces were cut out. In an environment of 23 ± 2 ° C. and relative humidity of 65 ± 15%, the test pieces are bonded to each other for 10 seconds under a load of 100 g / cm ² , and the adhesive strength (tack) when the test pieces are peeled off in three stages. evaluated. When the tack of the rubber composition of Comparative Example 4 is 2, the tack is stronger than the rubber composition of Comparative Example 4, 3 when the tack is equivalent to the rubber composition of Comparative Example 4, and the tack is weaker than that. The case was 1. When the value is 2, the tack is good.
(2) Rolling resistance performance A 40 mm long x 7 mm wide test piece 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 temperature of 60 ° C and a frequency. Tan δ was measured under the conditions of 10 Hz, static strain 10%, and dynamic strain 2%, 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 4 is 100. In addition, the rolling resistance performance of a rubber composition is so favorable that a numerical value is small.
(3) Tensile strength retention after heat aging (%)
The rubber composition sheets prepared in the examples and comparative examples were heated at 100 ° C. for 48 hours to be thermally aged, and then a dumbbell-shaped test piece was punched out according to JIS3, and a JIS-made tensile tester was used. The tensile strength at break was measured according to K6251. In addition, the tensile strength at break was measured in the same manner for the sheet not thermally deteriorated. Based on the following formula, the tensile strength retention after heat aging was calculated. Note that the closer the value is to 100, the smaller the change in physical properties after heat deterioration and the better the heat resistance.
[Tensile strength retention after thermal degradation (%)] = [Tensile fracture strength after thermal degradation] / [Tensile fracture strength before thermal degradation] × 100

  From Examples 3 to 4 and Comparative Example 4, it is understood that a rubber composition excellent in rolling resistance performance can be obtained by using a farnesene polymer having a specific catalyst residue amount. From Examples 3 to 4 and Comparative Example 3, by using a farnesene polymer in which the amount of catalyst residue is within the range of the present invention, the tack is good and the processability is excellent, and the rolling resistance performance and the heat resistance are combined. It can be seen that a rubber composition is obtained.

  The rubber composition of the present invention is excellent in processability, and when a crosslinkable rubber composition is obtained by adding a crosslinking agent, it gives a crosslinked product having excellent mechanical strength and improved heat resistance. It can be suitably used for industrial members such as industrial belts and industrial rubber hoses. In particular, it is useful when used in tire applications and the like because the rolling resistance performance is improved.

Claims (11)

A polymer comprising a solid rubber (A), at least one filler (B) selected from carbon black and silica, and a monomer unit derived from farnesene, derived from a metal catalyst used in the production of the polymer A rubber composition containing a polymer (C) having a catalyst residue amount of 0 to 200 ppm in terms of metal,
A rubber composition containing 20 to 150 parts by mass of the filler (B) and 0.1 to 30 parts by mass of the polymer (C) with respect to 100 parts by mass of the solid rubber (A).   The rubber composition of Claim 1 whose melt viscosity in 38 degreeC of the said polymer (C) is 0.1-3,000 Pa.s.   The rubber composition according to claim 1 or 2, wherein the polymer (C) has a weight average molecular weight (Mw) of 2,000 to 500,000.   The rubber composition according to any one of claims 1 to 3, wherein the carbon black has an average particle diameter of 5 to 100 nm and the silica has an average particle diameter of 0.5 to 200 nm.   The rubber composition in any one of Claims 1-4 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 5, wherein the solid rubber (A) is one or more selected from natural rubber, styrene butadiene rubber, butadiene rubber, and isoprene rubber.   The rubber composition according to claim 6, wherein the styrene-butadiene rubber has a weight average molecular weight of 100,000 to 2.5 million.   The rubber composition according to claim 6 or 7, wherein the styrene-butadiene rubber has a styrene content of 0.1 to 70 mass%.   The rubber composition according to any one of claims 6 to 8, wherein the butadiene rubber has a weight average molecular weight of 90,000 to 2,000,000.   The rubber composition in any one of Claims 6-9 whose vinyl content of the said butadiene rubber is 50 mass% or less.   A tire using at least a part of the rubber composition according to claim 1.