JP6262487B2 - Rubber composition and tire - Google Patents

Description

  The present invention relates to a rubber composition and a tire using the rubber composition.

  Pneumatic tires are required to have excellent handling stability (dry grip performance) on dry road surfaces and steering stability (wet grip performance) on wet road surfaces, and also excellent mechanical strength and durability. It has been demanded. In order to improve durability, a rubber composition containing carbon black or silica is generally used as a rubber reinforcing agent. However, since the rubber composition has a high viscosity, workability is poor, and as a processability improver. Process oils and liquid polymers are used. However, when the conventional processability improver is used, the balance between dry grip performance, wet grip performance and mechanical strength is not sufficiently improved, although the processability is improved.

As a rubber composition for improving the above properties in a well-balanced manner, Patent Document 1 discloses a rubber composition for tires containing a rubber component containing butadiene rubber and styrene butadiene rubber and silica in a specific ratio. .
Patent Document 2 describes a tire rubber composition in which silica, aluminum hydroxide, and a specific silane coupling agent are blended in a predetermined ratio.
However, tires using the rubber composition described in these patent documents cannot be said to have a sufficiently high level of mechanical strength, wet grip performance and workability, and also satisfy dry grip performance. More improvements are desired.
Although Patent Documents 3 and 4 describe polymers of β-farnesene, practical applications have not been sufficiently studied.

JP 2012-031308 A JP 2011-148952 A International Publication No. 2010/027463 International Publication No. 2010/027464

  The present invention has been made in view of the above circumstances, and has a rubber composition that is excellent in processability at the time of manufacture and can provide a tire having a high level of mechanical strength, dry grip performance, and wet grip performance. Provided is a tire using the rubber composition.

  As a result of intensive studies, the present inventors have found that when a specific copolymer containing a monomer unit derived from an aromatic vinyl compound and a monomer unit derived from farnesene is used in a rubber composition, it is processed during production. It was found that the mechanical strength, dry grip performance and wet grip performance of a tire manufactured using this rubber composition were improved, and the present invention was completed.

That is, the present invention
[1] A copolymer (A) containing a monomer unit (a) derived from an aromatic vinyl compound and a monomer unit (b) derived from farnesene, a rubber component (B), carbon black (C) and And / or a rubber composition containing silica (D), wherein the copolymer (A) has a weight average molecular weight (Mw) of 2,000 to 200,000, and the monomer unit (a) And the ratio of the monomer unit (a) with respect to the sum total of (b) is 30-70 mass%, and the said copolymer (A) is 0.1-100 with respect to 100 mass parts of said rubber components (B). A rubber composition containing 0.1 to 150 parts by mass of carbon black (C) and / or silica (D),
[2] A tire using at least a part of the rubber composition,
About.

  According to the present invention, a rubber composition that is excellent in processability at the time of manufacture, can provide a tire having a high level of mechanical strength, dry grip performance, and wet grip performance, and a tire using the rubber composition. Can be provided.

[Rubber composition]
The rubber composition of the present invention comprises a copolymer (A) comprising a monomer unit (a) derived from an aromatic vinyl compound and a monomer unit (b) derived from farnesene, a rubber component (B), carbon A rubber composition containing black (C) and / or silica (D), wherein the copolymer (A) has a weight average molecular weight (Mw) of 2,000 to 200,000, The ratio of the monomer unit (a) to the total of the body units (a) and (b) is 30 to 70% by mass, and the copolymer (A) is added to 100 parts by mass of the rubber component (B). 0.1-100 mass parts, 0.1-150 mass parts of carbon black (C) and / or silica (D) are contained.

<Copolymer (A)>
The copolymer (A) is a copolymer containing a monomer unit (a) derived from an aromatic vinyl compound and a monomer unit (b) derived from farnesene. The copolymer (A) may be in any polymerization form such as random or block, but a random copolymer is preferred from the viewpoint of obtaining a tire excellent in wear resistance and mechanical strength.

  Examples of the aromatic vinyl compound constituting the monomer unit (a) include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, and 4-t-butyl. Styrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) Aromatic vinyl compounds such as styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, N, N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, and divinylbenzene Etc. Of these, styrene, α-methylstyrene, and 4-methylstyrene are preferable, and styrene is more preferable. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The monomer unit (b) may be a monomer unit derived from α-farnesene, or may be a monomer unit derived from β-farnesene represented by the following formula (I). A monomer unit derived from β-farnesene is preferred. Note that α-farnesene and β-farnesene may be used in combination.

The weight average molecular weight (Mw) of the copolymer (A) is 2,000 to 200,000, preferably 5,000 to 100,000, more preferably 7,000 to 70,000, and 8,000. More preferred is ˜50,000. When the weight average molecular weight of the copolymer (A) is within the above range, processability is improved, and the mechanical strength, dry grip performance and wet grip performance of a tire using the rubber composition of the present invention are improved.
In the present specification, the weight average molecular weight of the copolymer (A) is a standard polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC). In the present invention, two or more copolymers (A) having different weight average molecular weights may be used in combination.

  The melt viscosity at 38 ° C. of the copolymer (A) is preferably 0.1 to 3,000 Pa · s, more preferably 1.5 to 2,000 Pa · s, and further preferably 2.0 to 1,500 Pa · s. Preferably, 2.5 to 1,000 Pa · s is even more preferable. When the melt viscosity of the copolymer (A) is within the above range, kneading of the resulting rubber composition becomes easy and processability is improved. Moreover, the mechanical strength, dry grip performance, and wet grip performance of a tire using the rubber composition of the present invention are improved. In the present specification, the melt viscosity of the copolymer (A) is a value determined by the method described in the examples described later.

  The ratio of the monomer unit (a) to the total of the monomer units (a) and (b) in the copolymer (A) needs to be 30 to 70% by mass. When the monomer unit (a) is contained in an amount of 30% by mass or more, the glass transition temperature of the copolymer (A) shifts to a high temperature region, so that the glass transition temperature of the rubber composition of the present invention also shifts to a high temperature region. And when the rubber composition of this invention is used for a tire, for example, dry grip performance and wet grip performance can be improved greatly. 30-65 mass% is more preferable, and, as for the ratio of the monomer unit (a) with respect to the sum total of monomer units (a) and (b), 35-60 mass% is still more preferable.

  1.0-4.0 are preferable, as for the molecular weight distribution (Mw / Mn) of a copolymer (A), 1.0-3.0 are more preferable, and 1.0-2.0 are still more preferable. It is more preferable that Mw / Mn is in the above-mentioned range, since the dispersion of the viscosity of the obtained copolymer is small.

  The glass transition temperature (Tg) obtained by differential thermal analysis of the copolymer (A) is preferably -95 ° C to 0 ° C, more preferably -80 ° C to 0 ° C, and -70. More preferably, it is 0 degreeC-0 degreeC, and it is most preferable that it is -60 degreeC-0 degreeC. When the Tg of the copolymer (A) is within the above range, the dry grip performance and wet grip performance of a tire using the rubber composition of the present invention are improved.

The copolymer (A) is only required to be a copolymer of at least an aromatic vinyl compound and farnesene, and other monomers, an aromatic vinyl compound, and farnesene within a range not impairing the effects of the present invention. And a copolymer thereof.
Examples of other monomers include butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3 -Conjugated dienes such as octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene and chloroprene.
The proportion of the other monomer in the copolymer (A) is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less.

[Method for producing copolymer]
The copolymer (A) is preferably produced by a method of copolymerizing at least an aromatic vinyl compound and farnesene. Specifically, it can be produced by a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, a solution polymerization method or the like. Of these, the solution polymerization method is preferred.
(Bulk polymerization method)
A known method can be applied as the bulk polymerization method. For example, it can be carried out by stirring and mixing farnesene and aromatic vinyl compound as raw materials and polymerizing in the absence of a solvent with a radical polymerization initiator.
Examples of the radical polymerization initiator include azo compounds, peroxide compounds, and redox compounds. Particularly, azobisisobutyronitrile, tert-butyl peroxypivalate, di-tert-butyl peroxide, i -Butyryl peroxide, lauroyl peroxide, succinic acid peroxide, dicinnamyl peroxide, di-n-propyl peroxydicarbonate, tert-butylperoxyallyl monocarbonate, benzoyl peroxide, hydrogen peroxide, ammonium persulfate, etc. preferable.
Although superposition | polymerization temperature can be suitably selected according to the kind of radical polymerization initiator to be used, 0-200 degreeC is preferable normally and 0-120 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, sodium nitrite and the like.
Examples of the method for removing the residual monomer from the obtained copolymer include methods such as reprecipitation and heat distillation under reduced pressure.

(Emulsion polymerization method)
A known method can be applied as the emulsion polymerization method. For example, a predetermined amount of farnesene and an aromatic vinyl compound can be emulsified and dispersed in the presence of an emulsifier, and polymerized with 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.

A chain transfer agent can also be used to adjust the molecular weight of the resulting copolymer. 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, sodium nitrite and the like.
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 copolymer is recovered by coagulating the copolymer while adjusting the pH of the coagulation system to a predetermined value by adding an acid, and then separating the dispersion solvent. Next, the copolymer is obtained by washing with water, dehydrating, and drying. In the course of 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 copolymer.

(Solution polymerization method)
As a solution polymerization method for obtaining a copolymer, a known method can be applied. For example, using a Ziegler catalyst, a metallocene catalyst, or an anionically polymerizable active metal in a solvent, the farnesene monomer and an aromatic vinyl compound-derived monomer are polymerized in the presence of a polar compound if desired. Can be done.
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; and 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 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; dilithiomethane, dilithionaphthalene, Polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,4-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 the farnesene polymer, but is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass in total of the monomer units (a) and (b). .
The organoalkali metal compound can also be used as an organoalkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine and dibenzylamine.

  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, toluene And aromatic hydrocarbons such as xylene.

The polar compound is used to adjust the microstructure of the farnesene site without deactivating the reaction in anionic polymerization, and is an ether compound such as dibutyl ether, diethyl ether, tetrahydrofuran, dioxane and ethylene glycol diethyl ether; pyridine; tetramethyl Examples include tertiary amines such as ethylenediamine and trimethylamine; alkali metal alkoxides such as potassium t-butoxide; 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.
From the viewpoint of producing a copolymer satisfying the molecular weight distribution range, the copolymer (A) is produced by anionic polymerization in the presence of an organometallic initiator such as the organoalkali metal compound. preferable.

The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 10 to 90 ° C. The polymerization mode may be either batch or continuous. Aromatic vinyl compound and farnesene are continuously or intermittently supplied to the reaction solution so that the composition ratio of the aromatic vinyl compound and farnesene in the polymerization system falls within the specified range, or adjusted to a specific composition ratio in advance. A copolymer can be produced by supplying a mixture of the aromatic vinyl compound and farnesene.
The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator.
The copolymer can be isolated by pouring the obtained polymerization reaction liquid into a poor solvent such as methanol to precipitate the copolymer, or washing the polymerization reaction liquid with water, separating, and drying.

{Modified copolymer}
The copolymer (A) may be a modified copolymer having a functional group introduced therein. Examples of the functional group include an amino group, an alkoxysilyl group, a hydroxyl group, an epoxy group, a carboxyl group, a carbonyl group, a mercapto group, an isocyanate group, and an acid anhydride.
Examples of the method for producing a modified copolymer include tin tetrachloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane, and tetraethoxysilane that can react with a polymerization active terminal before adding a polymerization terminator. Coupling agents such as 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane and 2,4-tolylene diisocyanate, 4,4'-bis (diethylamino) benzophenone and N-vinylpyrrolidone And the like, or a method of adding other modifiers described in JP2011-132298A. In addition, maleic anhydride or the like can be grafted onto the isolated copolymer.
In this modified copolymer, the position at which the functional group is introduced may be a terminal of the polymer or a side chain with respect to the polymer chain. Moreover, the said functional group can also be used 1 type or in combination of 2 or more types. The modifying agent is used in an amount of 0.01 to 100 molar equivalents, preferably 0.01 to 10 molar equivalents, relative to the organic alkali metal compound.

<Rubber component (B)>
Examples of the rubber component (B) include natural rubber, styrene butadiene rubber (hereinafter referred to as SBR), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, ethylene propylene diene rubber, and butadiene acrylonitrile copolymer rubber. And rubber such as chloroprene rubber. Among these, SBR, natural rubber, butadiene rubber, and isoprene rubber are more preferable, and SBR and natural rubber are more preferable. These rubbers may be used alone or in combination of two or more.

[Natural rubber]
Examples of the natural rubber used in the rubber component (B) 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 hydroxylated natural. Examples thereof include modified natural rubber such as rubber, hydrogenated natural rubber, and grafted natural rubber. Among these, STR20, SMR20, and RSS # 3 are preferable from the viewpoint of little variation in quality and easy availability.

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

(SBR)
As the SBR, a general one used for tire applications can be used, and specifically, the styrene content is preferably 0.1 to 70% by mass, and more preferably 5 to 50% 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.
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. When the Tg is in the above range, the increase in viscosity can be suppressed and the 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 preferable.
Emulsion polymerization styrene butadiene rubber (E-SBR) can be produced by a usual 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 emulsion polymerization is performed with a radical polymerization initiator. In order to adjust the molecular weight of the obtained E-SBR, a chain transfer agent can also be used. 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.

  Solution-polymerized styrene butadiene rubber (S-SBR) can be produced by an ordinary solution polymerization method. For example, using an active metal capable of anion polymerization in a solvent, styrene and butadiene are polymerized in the presence of a polar compound as desired. . The active metal capable of anion polymerization is preferably an alkali metal or alkaline earth metal, and more preferably an organic alkali metal compound among the alkali metals. 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. The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator. A polymerization terminal modifier may be added before the polymerization terminator is 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 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 hydroxyl group, an epoxy group, and a carboxyl group. In this modified SBR, the position at which the functional group is introduced may be the terminal of the polymer or a side chain with respect to the polymer chain.

(Isoprene rubber)
As the isoprene rubber, for example, a commercially available isoprene rubber polymerized using a Ziegler catalyst, a lanthanoid rare earth metal catalyst, an organic alkali metal compound, or the like 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 is 50% by mass or less, the rolling resistance performance is good. 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 of the isoprene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When the weight average molecular weight is in the above range, workability and mechanical strength are improved.
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.

(Butadiene rubber)
As the butadiene rubber, for example, a commercially available butadiene rubber polymerized using a Ziegler catalyst, a lanthanoid rare earth metal catalyst, an organic alkali metal compound, or the like 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 is 50% by mass or less, the rolling resistance performance is good. 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 of the butadiene rubber is preferably 90,000 to 2,000,000, more preferably 150,000 to 1,500,000, still more preferably 250,000 to 800,000. When the weight average molecular weight is in the above range, workability and mechanical strength are improved.
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.

  As a synthetic rubber other than SBR, isoprene rubber and butadiene rubber, one or more of butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber and the like can be used. Moreover, these manufacturing methods are not specifically limited, What is marketed can be used.

  In the present invention, by using the rubber component (B) and the copolymer (A) in combination, processability is improved, and the mechanical strength and dry grip performance of a tire using the rubber composition of the present invention are improved. And wet grip performance is improved. When two or more synthetic rubbers are mixed and used, the combination can be arbitrarily selected within a range not impairing the effects of the present invention, and the physical property values can be adjusted by the combination.

  The content of the copolymer (A) in the rubber composition is 0 with respect to 100 parts by mass of the rubber component (B) from the viewpoint of improving the mechanical strength, dry grip performance and wet grip performance of the obtained tire. 0.1 to 100 parts by mass, preferably 0.5 to 50 parts by mass, and more preferably 1 to 30 parts by mass.

  The rubber composition of the present invention contains the polymer (A), the rubber component (B), carbon black (C) and / or silica (D). That is, the rubber composition of the present invention may contain either carbon black (C) or silica (D), or may contain both carbon black (C) and silica (D).

<Carbon black (C)>
In the present invention, carbon black (C) 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 and mechanical strength.
As a commercial product of furnace black, Mitsubishi Chemical Corporation "Dia Black", Tokai Carbon Co., Ltd. "Shiest" etc. are mentioned, for example. Examples of commercially available acetylene black include “DENKA BLACK” manufactured by Denki Kagaku Kogyo Co., Ltd. As a commercially available product of Ketjen Black, for example, “ECP600JD” manufactured by Lion Corporation can be cited.

From the viewpoint of improving the wettability and dispersibility to the copolymer (A) and the rubber component (B), the carbon black (C) is acid-treated with nitric acid, sulfuric acid, hydrochloric acid, or a mixed acid thereof, or the presence of air. You may perform the surface oxidation process by the below heat processing. 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, tetrabora). Acid) and salts thereof, boron carbide (for example, B ₄ C, B ₆ C, etc.), boron nitride (BN), and other boron compounds are preferably used.

The average particle diameter of carbon black (C) can be adjusted by pulverization or the like. For the pulverization of carbon black (C), a high-speed rotary pulverizer (hammer mill, pin mill, cage mill), various ball mills (rolling mill, vibration mill, planetary mill), agitation mill (bead mill, attritor, distribution pipe mill, An annular mill) can be used.
The average particle size of the carbon black (C) used in the rubber composition of the present invention is preferably 5 to 100 nm from the viewpoint of improving carbon black dispersibility, tire wet grip performance, dry grip performance and mechanical strength. ˜80 nm is more preferable.
In addition, the average particle diameter of carbon black (C) can be calculated | required by measuring the diameter of particle | grains with a transmission electron microscope, and calculating the average value.

  When silica (D) is not contained in the rubber composition of the present invention, the content of carbon black (C) is 0.1 to 150 parts by mass with respect to 100 parts by mass of the rubber component (B), and 5 to 130. A mass part is preferable, 10-120 mass parts is more preferable, 20-110 mass parts is still more preferable. When the content of carbon black (C) is within the above range, the dispersibility of carbon black is improved, and the wet grip performance, dry grip performance and mechanical strength of the tire are improved.

<Silica (D)>
Examples of silica (D) include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate and the like. Among these, wet silica is preferable from the viewpoint of further improving workability, mechanical strength, and wear resistance. These may be used alone or in combination of two or more.
The average particle diameter of the silica (D) is preferably 0.5 to 200 nm from the viewpoint of improving the dispersibility of the silica, the wet grip performance of the tire using the rubber composition of the present invention, the dry grip performance and the mechanical strength. 5-150 nm is more preferable, 10-100 nm is still more preferable, and 10-60 nm is still more preferable.
In addition, the average particle diameter of silica (D) can be calculated | required by measuring the diameter of particle | grains with a transmission electron microscope, and calculating the average value.

  When carbon black (C) is not contained in the rubber composition of the present invention, the content of silica (D) is 0.1 to 150 parts by mass with respect to 100 parts by mass of the rubber component (B). -130 mass parts is preferable, 10-120 mass parts is more preferable, 20-110 mass parts is still more preferable. When the content of silica is within the above range, silica dispersibility, tire wet grip performance, dry grip performance and mechanical strength are improved.

  In the rubber composition of the present invention, when both carbon black (C) and silica (D) are contained, the total content is 0.1 to 150 with respect to 100 parts by mass of the rubber component (B). It is a mass part, 5-130 mass parts is preferable, 10-120 mass parts is more preferable, 20-110 mass parts is still more preferable. When both carbon black (C) and silica (D) are contained, the compounding ratio of each component is not particularly limited, and can be appropriately adjusted according to desired performance.

<Optional component>
(Silane coupling agent)
The rubber composition of the present invention preferably contains 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 Examples include dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide and 3-trimethoxysilylpropyl methacrylate monosulfide. It is done.
Examples of mercapto compounds include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like.
Examples of the vinyl compound include vinyltriethoxysilane and vinyltrimethoxysilane.
Examples of amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, and 3- (2-aminoethyl) aminopropyltrimethoxysilane. Etc.
Examples of glycidoxy compounds include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane. 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, and 2-chloroethyltriethoxysilane.
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 additive effect and cost.

  When the silane coupling agent is contained, the content is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and 1 to 15 parts by mass with respect to 100 parts by mass of silica (D). Part is more preferred. When the content of the silane coupling agent is within the above range, the dispersibility, the coupling effect, the reinforcing property, and the wear resistance of the tire using the rubber composition of the present invention are improved.

(Other fillers)
The rubber composition of the present invention may be prepared by adding carbon black (as needed) for the purpose of improving mechanical strength, improving physical properties such as heat resistance and weather resistance, adjusting the hardness, and improving economy by including a bulking agent. A filler other than C) and silica (D) may further be contained.

  The filler other than the carbon black (C) and silica (D) is appropriately selected depending on the application. For example, organic filler, clay, talc, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, One or more inorganic fillers such as barium sulfate, titanium oxide, glass fiber, fibrous filler, and glass balloon can be used. When the above filler is contained in the rubber composition of the present invention, the content thereof is preferably 0.1 to 120 parts by mass, more preferably 5 to 90 parts by mass with respect to 100 parts by mass of the rubber component (B). 10-80 mass parts is still more preferable. When the content of the filler is within the above range, the mechanical strength is further improved.

  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), process oils such as paraffin oil and naphthene oil, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, C9 resins, rosin resins, coumarone / indene resins, phenolic resins A liquid polymer such as a resin component such as a resin, a low molecular weight polybutadiene, a low molecular weight polyisoprene, a low molecular weight styrene butadiene copolymer, and a low molecular weight styrene isoprene copolymer can be appropriately used as a softening agent. The copolymer may be in any polymerization form such as block or random. The weight average molecular weight of the liquid polymer is preferably 500 to 100,000 from the viewpoint of processability. Further, the rubber composition of the present invention may further contain a farnesene homopolymer as long as the effects of the invention are not impaired.

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 One or more additives such as an agent and a fragrance may be contained.
Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, lactone compounds, and hydroxyl compounds.
Examples of the antiaging agent include amine-ketone compounds, imidazole compounds, amine compounds, phenol compounds, sulfur compounds, and phosphorus compounds.

  The rubber composition of the present invention is preferably used by adding a crosslinking agent and crosslinking. Examples of the crosslinking agent include sulfur and 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 organometallic halogens. And silane compounds other than silane coupling agents. Of these, sulfur and sulfur compounds are preferred. These may be used alone or in combination of two or more. As for content of a crosslinking agent, 0.1-10 mass parts is preferable with respect to 100 mass parts of rubber components (B).

  When sulfur is used as the cross-linking agent, it is preferable to use a vulcanization aid or a vulcanization accelerator in combination. Examples of the vulcanization aid include fatty acids such as stearic acid and metal oxides such as zinc white. Examples of the vulcanization accelerator include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds or aldehyde-ammonia compounds, imidazoline compounds. And xanthate compounds. These may be used alone or in combination of two or more. The content of these vulcanization aids and vulcanization accelerators is preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the rubber component (B).

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

[tire]
The tire of the present invention uses at least a part of the rubber composition of the present invention. Therefore, mechanical strength, dry grip performance, and wet grip performance are good.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

Each component used in the examples and comparative examples is as follows.
Copolymer (A): Copolymer (A-1) obtained in Production Example 1
Copolymer (A ′): Copolymer (A′-1) obtained in Production Example 2
Polyfarnesene: Polyfarnesene rubber component (B) obtained in Production Example 3: Styrene butadiene rubber “JSR1500” (manufactured by JSR Corporation)
Weight average molecular weight 450,000
Styrene content 23.5% by mass (produced by emulsion polymerization method)
Carbon Black (C-1): Dia Black H (Mitsubishi Chemical Corporation)
Average particle size 30nm
Silica (D-1): ULTRASIL 7000GR (Evonik Degussa Japan)
Wet silica, average particle size 14nm

Silane coupling agent: Si75 (Evonik Degussa Japan)
Stearic acid: LUNAC S-20 (manufactured by Kao Corporation)
Zinc flower: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.)
Anti-aging agent (1): NOCRACK 6C (manufactured by Ouchi Shinsei Chemical Co., Ltd.)
Anti-aging agent (2): ANTAGE RD (manufactured by Kawaguchi Chemical Industry Co., Ltd.)
Sulfur: Fine sulfur 200 mesh (manufactured by Tsurumi Chemical Co., Ltd.)
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.)

Production Example 1: Production of β-farnesene-styrene copolymer (A-1) In a pressure-resistant container that was purged with nitrogen and dried, 1284 g of cyclohexane as a solvent and sec-butyllithium as a initiator (10.5 mass% cyclohexane solution) After charging 156.4 g and raising the temperature to 50 ° C., 3.5 g of tetrahydrofuran was added, and a mixture of styrene (a) and β-farnesene (b) prepared in advance (880 g of styrene (a) and β-farnesene ( b) 880 g was mixed in a cylinder) 1760 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain a β-farnesene-styrene copolymer (A-1). Table 1 shows the physical properties of the obtained β-farnesene-styrene copolymer (A-1).

Production Example 2: Production of β-farnesene-styrene copolymer (A′-1) 1500 g of cyclohexane as a solvent and sec-butyllithium (10.5 mass% cyclohexane solution as an initiator) in a pressure-resistant container which was purged with nitrogen and dried. ) 112.6 g was charged and the temperature was raised to 50 ° C., 3 g of tetrahydrofuran was added, and a mixture of styrene (a) and β-farnesene (b) prepared in advance (345 g of styrene (a) and β-farnesene (b) ) 1155 g was mixed in a cylinder) 1500 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain a β-farnesene-styrene copolymer (A′-1). Table 1 shows the physical properties of the obtained β-farnesene-styrene copolymer (A′-1).

Production Example 3: Production of polyfarnesene After charging 241 g of cyclohexane as a solvent and 28.3 g of sec-butyllithium (10.5% by mass cyclohexane solution) as a solvent in a pressure-resistant container purged with nitrogen and dried, the temperature was raised to 50 ° C. , 342 g of β-farnesene was added and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerized reaction liquid after washing was separated from water and dried at 70 ° C. for 12 hours to obtain polyfarnesene having physical properties shown in Table 1.

(Measurement method of weight average molecular weight)
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the copolymer (A), the copolymer (A ′) and the polyfarnesene were 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 copolymer (A), copolymer (A ′) and polyfarnesene was measured with a Brookfield B-type viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

(Measurement method of glass transition temperature)
Copolymer (A), copolymer (A ′) and polyfarnesene were collected in 10 mg aluminum pans, and thermograms were measured at a heating rate of 10 ° C./min by differential scanning calorimetry (DSC). The peak top value of was taken as the glass transition temperature.

<Example 1 and Comparative Examples 1 and 2>
According to the formulation described in Table 2, copolymer (A), copolymer (A ′), polyfarnesene, rubber component (B), carbon black (C), silica (D), silane coupling agent, stearic acid The zinc white and the anti-aging agent were respectively put into a closed Banbury mixer, kneaded for 6 minutes so that the starting temperature was 75 ° C. and the resin temperature was 160 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was put in a mixing roll, sulfur and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain 960 g of a rubber composition.
The obtained rubber composition is press-molded (160 ° C., 15 to 25 minutes) to prepare a vulcanized sheet (thickness 2 mm), and the tensile rupture strength, dry grip performance and wet grip performance are evaluated based on the following methods. did. The results are shown in Table 2.

(1) Tensile strength at break The JIS No. 3 dumbbell-shaped test piece was punched out from the vulcanized sheets prepared in Examples and Comparative Examples, and the tensile strength at break was measured according to JIS K 6251 using an Instron tensile tester. did. The numerical values of each Example and Comparative Example in Table 2 are relative values when the value of Comparative Example 2 is 100. The larger the value, the better the breaking property and the better the mechanical strength.

(2) Dry grip performance A test piece having a length of 40 mm, a width of 7 mm, and a thickness of 2 mm was cut out from the vulcanized sheets prepared in Examples and Comparative Examples, and a measurement temperature of 25 ° C was measured using a dynamic viscoelasticity measuring device manufactured by GABO. Tan δ was measured under the conditions of a frequency of 10 Hz, a static strain of 10%, and a dynamic strain of 2%, and used as an index of dry grip performance. The numerical value of each Example and Comparative Example is a relative value when the value of Comparative Example 2 is set to 100. The results are shown in Table 2. The larger the value, the better the dry grip performance.

(3) Wet grip performance A test piece having a length of 40 mm, a width of 7 mm, and a thickness of 2 mm was cut out from the vulcanized sheets prepared in Examples and Comparative Examples, and measured using a GABO dynamic viscoelasticity measuring device at a measurement temperature of 0 ° C. and a frequency. Tanδ was measured under the conditions of 10 Hz, static strain 10%, and dynamic strain 2%, and used as an index of wet grip performance. The numerical values of each Example and Comparative Example in Table 2 are relative values when the value of Comparative Example 2 is 100. It shows that wet grip performance is so favorable that a numerical value is large.

  From the results of Examples and Comparative Examples, the rubber composition of Example 1 has higher tensile rupture strength and excellent mechanical strength than the rubber compositions of Comparative Examples 1 and 2, and dry grip performance and wet grip performance. It turns out that it is also excellent.

Claims (8)

Copolymer (A) containing monomer unit (a) derived from aromatic vinyl compound and monomer unit (b) derived from farnesene, rubber component (B), carbon black (C) and silica (D And a rubber composition containing
The weight average molecular weight (Mw) of the copolymer (A) is 2,000 to 200,000, and the ratio of the monomer unit (a) to the total of the monomer units (a) and (b) is from 50 to 60 mass%,
0.1-100 mass parts of said copolymer (A), carbon black (C), and silica (D) are contained 0.1-150 mass parts in total with respect to 100 mass parts of said rubber components (B). ,
The carbon black (C) has an average particle size of 5 to 100 nm,
The rubber composition whose average particle diameter of the said silica (D) is 0.5-200 nm.
A tire using at least a part of the rubber composition.   The rubber composition according to claim 1, wherein the monomer unit (b) is a monomer unit derived from β-farnesene.   The rubber composition according to claim 1 or 2, wherein the copolymer (A) has a molecular weight distribution (Mw / Mn) of 1.0 to 4.0.   The rubber composition according to any one of claims 1 to 3, wherein the aromatic vinyl compound is at least one selected from styrene, α-methylstyrene, and 4-methylstyrene.   The rubber composition in any one of Claims 1-4 whose melt viscosity in 38 degreeC of the said copolymer (A) is 0.1-3,000 Pa.s.   The rubber composition according to any one of claims 1 to 5, wherein the rubber component (B) is at least one selected from styrene butadiene rubber, natural rubber, butadiene rubber, and isoprene rubber. The rubber composition according to any one of claims 1 to 6, wherein the glass transition temperature of the copolymer (A) is -60 to 0 ° C. Tire using at least a portion of the rubber composition according to any one of claims 1-7.