JP2019099674A - Tire rubber composition and pneumatic tire - Google Patents

Abstract

To provide a tire rubber composition having excellent on-ice performance, and a pneumatic tire prepared therewith.SOLUTION: This invention relates to a tire rubber composition containing a rubber component, a farnesene polymer and eggshell powder.SELECTED DRAWING: None

Description

The present invention relates to a rubber composition for a tire, and a pneumatic tire using the same.

Studless tires (tires for winter) and all-season tires are designed in consideration of low temperature characteristics. For example, Patent Document 1 proposes a rubber composition containing a specific resin. However, there is a need for further improvement on the performance on ice.

JP, 2013-249423, A

An object of the present invention is to solve the above-mentioned problems and to provide a rubber composition for a tire having excellent performance on ice, and a pneumatic tire manufactured using the same.

The present invention relates to a rubber composition for a tire containing a rubber component, a farnesene-based polymer and eggshell powder.

The farnesene-based polymer is preferably a liquid farnesene-based polymer.

The farnesene-based polymer is preferably a copolymer of farnesene and butadiene.

It is preferable that the average particle diameter of the said eggshell powder is 250 micrometers or less.

The content of the isoprene rubber is preferably 30% by mass or more and the content of the butadiene rubber is preferably 30% by mass or more in 100% by mass of the rubber component.

The present invention also relates to a pneumatic tire having a tread made using the above rubber composition.

The pneumatic tire is preferably a studless tire or an all season tire.

According to the present invention, since it is a rubber composition for tires containing a farnesene-based polymer and eggshell powder together with a rubber component, a pneumatic tire excellent in on-ice performance can be provided.

The rubber composition for a tire of the present invention contains a farnesene-based polymer and eggshell powder together with a rubber component. This provides good ice performance over a long period of time.

When eggshell powder is compounded, unevenness occurs on the rubber surface when eggshell powder is detached during traveling, and a scratching effect on the upper surface of ice is exhibited, thereby improving the performance on ice. However, in the conventional rubber composition, the rubber hardens due to low temperature or aging, and the eggshell powder is difficult to be detached, and the scratching effect may be impaired.
On the other hand, in the present invention, the incorporation of the farnesene-based polymer suppresses the curing of the rubber at low temperatures and aging, and eggshell powder is easily detached. Further, by suppressing the curing of the rubber, the followability to the road surface unevenness is improved. It is considered that these actions make it possible to exert good ice performance over a long period of time.

(Rubber composition)
Examples of rubber components that can be used in the present invention include diene rubbers such as isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), and styrene isoprene butadiene rubber (SIBR). The rubber component may be used alone or in combination of two or more. Among them, isoprene rubber and BR are preferable, and combined use of isoprene rubber and BR is more preferable.

The BR is not particularly limited, and, for example, BR having a high cis content, BR containing syndiotactic polybutadiene crystals, and the like can be used. These may be used alone or in combination of two or more. The cis content of BR is preferably 90% by mass or more because the abrasion resistance performance is good.

BR may be non-modified BR or modified BR. These may be used alone or in combination of two or more.
The modified BR may be any BR having a functional group capable of interacting with a filler such as silica, for example, terminal modified by modifying at least one end of BR with a compound having the above functional group (modifier). BR (terminal-modified BR having the above functional group at the end), main chain modified BR having the above functional group in the main chain, main chain terminal modified BR having the main chain and the above functional group at the end (eg, main chain The main chain terminal modified BR having the above functional group, at least one end of which is modified with the above modifier, or modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule, And terminal-modified BR in which an epoxy group is introduced. These may be used alone or in combination of two or more.

Examples of the functional group include amino group, amide group, silyl group, alkoxysilyl group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, mercapto group, sulfide group, disulfide Group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group etc. . In addition, these functional groups may have a substituent. Among them, an amino group (preferably an amino group in which a hydrogen atom possessed by an amino group is substituted by an alkyl group having 1 to 6 carbon atoms) or an alkoxy group (preferably) because the effects of the present invention are more suitably obtained. A C1-C6 alkoxy group) and an alkoxy silyl group (preferably a C1-C6 alkoxy silyl group) are preferable.

As BR, for example, products such as Ube Industries, Ltd., JSR Ltd., Asahi Kasei Corporation, Nippon Zeon Ltd., etc. can be used.

When BR is contained, the content of BR in 100% by mass of the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass % Or less, more preferably 45% by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

Examples of isoprene rubber include natural rubber (NR), isoprene rubber (IR), modified natural rubber, modified NR, modified IR and the like. As NR, for example, those common in the tire industry, such as SIR20, RSS # 3 and TSR20, can be used. The IR is not particularly limited, and, for example, IR 2200 or the like common in the tire industry can be used. As modified natural rubber, high purity natural rubber (UPNR) etc., as modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber etc., as modified IR, epoxidized Examples include isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber and the like. These may be used alone or in combination of two or more. Among them, natural rubber (NR) is preferable.

When the isoprene-based rubber is contained, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 55% by mass or more. Preferably it is 70 mass% or less, More preferably, it is 60 mass% or less. Within the above range, the effects of the present invention tend to be obtained better.

The total content of isoprene-based rubber and BR in 100% by mass of the rubber component is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and even 100% by mass Good. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition contains eggshell powder. Eggshell flour is obtained by crushing eggshells, and its main component is calcium carbonate.

The average particle size of eggshell powder is preferably 250 μm or less, more preferably 200 μm or less, still more preferably 100 μm or less, and preferably 10 μm or more, more preferably 60 μm or more. Within the above range, the effects of the present invention tend to be obtained better.
In addition, the average particle diameter of eggshell powder is measured using a particle size distribution measuring device.

As eggshell flour, products such as Green Techno 21 Co., Ltd., Kewpie Co., Ltd. can be used, for example.

The content of eggshell powder is preferably 5 parts by mass or more, more preferably 15 parts by mass or more from the viewpoint of performance on ice with respect to 100 parts by mass of the rubber component, and preferably from the viewpoint of abrasion resistance. It is 50 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 20 parts by mass or less.

The rubber composition contains a farnesene-based polymer. The farnesene-based polymer is a polymer obtained by polymerizing farnesene, and has a farnesene-based constitutional unit. Examples of farnesene include α-farnesene ((3E, 7E) -3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1). There exist isomers such as (6,10-dodecatriene), but (E) -β-farnesene having the following structure is preferred.

The farnesene-based polymer may be a farnesene homopolymer (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

As a vinyl monomer, styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5- t-Butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N, N-dimethylaminoethyl ester Styrene, N, N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, vinylxylene, Vinyl naphthale , Vinyl toluene, vinyl pyridine, diphenylethylene, and aromatic vinyl compounds such as tertiary amino group-containing diphenylethylene, butadiene, and the like conjugated diene compound such as isoprene. One of these may be used alone, or two or more may be used in combination. Among these, styrene and butadiene are preferable. That is, as farnesene-vinyl monomer copolymers, copolymers of farnesene and styrene (farnesene-styrene copolymers) and copolymers of farnesene and butadiene (farnesene-butadiene copolymers) are preferable, and farnesene-vinyl monomers are preferable. Butadiene copolymers are more preferred. The farnesene-butadiene copolymer has a structural unit similar to isoprene-based rubber and a structural unit similar to BR, and can improve the compatibility between isoprene-based rubber and BR. This gives better ice performance.

The farnesene-based polymer is preferably a liquid farnesene-based polymer. The liquid farnesene polymer is a farnesene polymer which is liquid at normal temperature (25 ° C.), and one having a weight average molecular weight (Mw) of 3,000 to 300,000 can be suitably used. The Mw of the liquid farnesene-based polymer is preferably 8,000 or more, more preferably 10,000 or more, and preferably 100,000 or less, more preferably 60,000 or less, still more preferably 50,000 or less.
Mw is based on a value measured by gel permeation chromatography (GPC) (Tosoh Corp. GPC-8000 series, detector: differential refractometer, column: TSKEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corp.) Can be determined by standard polystyrene conversion.

The glass transition temperature (Tg) of the farnesene-based polymer is preferably −100 ° C. or higher, more preferably −78 ° C. or higher, and preferably −10 ° C. or lower, more preferably −30 ° C. or lower, still more preferably − 54 ° C. or less. Within the above range, the effects of the present invention tend to be obtained better.
Tg is a value measured at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter (Q200) manufactured by TA Instruments Japan in accordance with JIS-K7121: 1987. .

The melt viscosity of the farnesene-based polymer is preferably 0.1 Pa · s or more, more preferably 0.7 Pa · s or more, and preferably 500 Pa · s or less, more preferably 100 Pa · s or less, still more preferably 13 Pa · s. s or less. Within the above range, the effects of the present invention tend to be obtained better.
The melt viscosity is a value measured at 38 ° C. using a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

In the farnesene-vinyl monomer copolymer, the copolymerization ratio (farnesene / vinyl monomer) of farnesene and vinyl monomer on a mass basis is preferably 40/60 to 90/10.

As farnesene polymers, for example, products such as Kuraray Co., Ltd. can be used.

The content of the farnesene-based polymer is preferably 5 parts by mass or more, more preferably 15 parts by mass or more from the viewpoint of performance on ice with respect to 100 parts by mass of the rubber component, and from the viewpoint of hardness and abrasion resistance Preferably it is 50 mass parts or less, More preferably, it is 30 mass parts or less, More preferably, it is 20 mass parts or less.

The rubber composition may contain a resin other than the farnesene-based polymer (hereinafter referred to as another resin).
Other resins are not particularly limited as long as they are generally used in the tire industry, and examples thereof include polyalkylene resins, coumarone indene resins, α-methylstyrene resins, terpene resins, acrylic resins, C5 resin, C9 resin, etc. are mentioned. These may be used alone or in combination of two or more. Among them, polyalkylene resins and terpene resins are preferable, and terpene resins are more preferable because the rubber can be plasticized, the dispersion of the filler can be promoted, and the effect of the present invention can be more suitably obtained.

The polyalkylene resin is not particularly limited as long as it is a resin having a unit derived from alkylene. For example, polyethylene resin, polypropylene resin, polybutylene resin, ethylene propylene resin, ethylene propylene styrene resin, ethylene styrene resin, propylene styrene resin, etc. Can be mentioned. Among these, ethylene propylene resin and ethylene propylene styrene resin are preferable.

The terpene resin is not particularly limited as long as it is a resin having a unit derived from a terpene compound, and, for example, polyterpene (resin obtained by polymerizing a terpene compound), terpene aromatic resin (terpene compound and aromatic compound) And resins obtained by copolymerizing them, and aromatic modified terpene resins (resins obtained by modifying a terpene resin with an aromatic compound) and the like.

The terpene compound is a hydrocarbon represented by the composition of (C ₅ H ₈ ) _n and an oxygen-containing derivative thereof, and is a monoterpene (C ₁₀ H ₁₆ ), a sesquiterpene (C ₁₅ H ₂₄ ), a diterpene (C ₂₀ H) ₃₂ ) Compounds having a terpene as a basic skeleton classified into, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-ferandrene, α-terpinene, γ-terpinene, Terpinolene, 1,8-cineole, 1,4-cineole, alpha-terpineol, beta-terpineol, gamma-terpineol and the like. The above-mentioned terpene compounds also include resin acids (rosin acids) such as abietic acid, neoabietic acid, parastringic acid, levopimaric acid, pimaric acid, isopimaric acid and the like. That is, the terpene-based resin also includes a rosin-based resin containing as a main component a rosin acid obtained by processing rosin. Examples of rosin resins include naturally occurring rosin resins (polymerized rosin) such as gum rosin, wood rosin and tall oil rosin, modified rosin resins such as maleic acid modified rosin resin, rosin modified phenolic resin, rosin glycerin ester and the like Examples thereof include rosin esters and disproportionated rosin resins obtained by disproportionating rosin resins.

The aromatic compound is not particularly limited as long as it is a compound having an aromatic ring, and examples thereof include phenol compounds such as phenol, alkylphenol, alkoxyphenol and unsaturated hydrocarbon group-containing phenol; naphthol, alkyl naphthol, alkoxy naphthol Naphthol compounds such as saturated hydrocarbon group-containing naphthol; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, unsaturated hydrocarbon group-containing styrene and the like. Among these, styrene is preferred.

0 degreeC or more is preferable, as for the softening point of other resin, 10 degreeC or more is more preferable, and 40 degreeC or more is still more preferable. Moreover, 160 degrees C or less is preferable, as for the said softening point, 140 degrees C or less is more preferable, and 100 degrees C or less is still more preferable. Within the above range, the effects of the present invention tend to be obtained better.
In the present invention, the softening point is a temperature at which a ball descends by measuring the softening point defined in JIS K 6220-1: 2001 using a ring and ball type softening point measuring device.

Other resins may be hydrogenated hydrogenated resins. The hydrogenation can be performed by a known method, and for example, catalytic hydrogenation with a metal catalyst, a method using hydrazine, and the like can be suitably used (JP-A-59-161415, etc.). For example, catalytic hydrogenation with a metal catalyst can be carried out by adding hydrogen under pressure in the presence of a metal catalyst in an organic solvent, and preferred examples of the organic solvent include tetrahydrofuran, methanol, ethanol and the like. It can be used for These organic solvents can be used singly or in combination of two or more. Moreover, as a metal catalyst, any of palladium, platinum, rhodium, ruthenium, nickel etc. can be used suitably, for example, These metal catalysts can be used individually by 1 type or in mixture of 2 or more types. . The pressure at the time of pressurization is preferably, for example, 1 to 300 kgf / cm ² .

In other resins, the hydrogenation rate of the double bond is 1 to 100%, preferably 2% or more, more preferably 5% or more, and still more preferably 8% or more. preferable. In addition, the upper limit of the hydrogenation rate of the double bond may possibly be changed in its preferable range due to the progress of manufacturing techniques such as pressure heating condition and catalyst in the hydrogenation reaction, improvement of productivity, etc. Although it has not been confirmed accurately at present, at present, for example, it is preferably 80% or less, more preferably 60% or less, still more preferably 40% or less, still more preferably 30% or less, 25% or less is particularly preferable.
In addition, this hydrogenation rate (hydrogenation rate) is a value computed by a following formula from each integral value of the double bond origin peak by ¹ H-NMR (proton NMR). In the present specification, the hydrogenation rate (hydrogenation rate) means the hydrogenation rate of double bonds.
(Hydration rate [%]) = {(A-B) / A} x 100
A: Integral value of double bond peak before hydrogen addition B: Integral value of double bond peak after hydrogen addition

As other resin, for example, Mitsui Chemical Co., Ltd., Straktoll Company, Yashara Chemical Co., Ltd., Arizona Chemical Co., Ltd., Nisshin Chemical Co., Ltd., Rutgers Chemicals Co., Ltd., Arakawa Chemical Co., Ltd., Maruzen Petrochemicals Co., Ltd. And Sumitomo Bakelite Co., Ltd., Tosoh Co., Ltd., Nippon Shokubai Co., Ltd., JX Energy Co., Ltd., Toagosei Co., Ltd., and the like.

When the other resin is contained, the content of the other resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, with respect to 100 parts by mass of the rubber component. Also, it is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and still more preferably 15 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain carbon black.
It does not specifically limit as a carbon black, N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762 etc. are mentioned. These may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 80 m ² / g or more, more preferably 100 m ² / g or more, and preferably 150 m ² / g or less, more preferably 130 m ² / g It is below. The effect of the present invention is suitably acquired as it is in the above-mentioned range.
In the present specification, N ₂ SA of carbon black is a value measured in accordance with JIS K 6217-2: 2001.

When carbon black is contained, the content of carbon black is preferably 5 parts by mass or more, more preferably 40 parts by mass or more, still more preferably 70 parts by mass or more, with respect to 100 parts by mass of the rubber component. Preferably it is 120 mass parts or less, More preferably, it is 100 mass parts or less, More preferably, it is 90 mass parts or less. Within the above range, the effects of the present invention are more suitably obtained.

The rubber composition may contain silica.
Examples of the silica include dry method silica (anhydrous silicic acid), wet method silica (hydrous silicic acid) and the like, but wet method silica is preferable because it has many silanol groups. These may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 70 m ² / g or more, more preferably 150 m ² / g or more, and preferably 300 m ² / g or less, more preferably 200 m ² / g or less It is. Within the above range, the effects of the present invention tend to be obtained better.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method in accordance with ASTM D3037-81.

As the silica, for example, products of Degussa, Rhodia, Tosoh Silica Corporation, Solvay Japan Ltd., Tokuyama Corporation etc. can be used.

When silica is contained, the content of silica is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, still more preferably 70 parts by mass or more, with respect to 100 parts by mass of the rubber component. It is 200 parts by mass or less, more preferably 150 parts by mass or less, still more preferably 100 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

The content of carbon black in the total 100% by mass of silica and carbon black is preferably 50% by mass or more, more preferably 80% by mass or more, and may be 100% by mass. Within the above range, the effects of the present invention tend to be obtained better.

When the rubber composition contains silica, it preferably further contains a silane coupling agent.
The silane coupling agent is not particularly limited. For example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, Bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis ( 3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilyl) disulfide 3) Disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, Sulfides such as triethoxysilylpropyl methacrylate monosulfide, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, NXT manufactured by Momentive, mercaptos such as NXT-Z, vinyltriethoxysilane, vinyl Vinyl compounds such as trimethoxysilane, amino compounds such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycid Glycidoxy type such as cypropyltrimethoxysilane, Nitro type such as 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, Chloro type such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane Etc. These may be used alone or in combination of two or more. Among them, mercapto-based silane coupling agents are preferable, from the viewpoint that the effects of the present invention tend to be obtained better.

Examples of silane coupling agents that can be used include products such as Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Amax Co., Ltd., Toray Dow Corning Co., Ltd., and the like.

When the silane coupling agent is contained, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass with respect to 100 parts by mass of silica. The amount is preferably 15 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain an oil.
The oils include, for example, process oils, vegetable oils and fats, or mixtures thereof. As the process oil, for example, paraffin-based process oil, aroma-based process oil, naphthene-based process oil and the like can be used. As vegetable oil, castor oil, cotton seed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, peanut oil, pine oil, pine tar, tall oil, corn oil, corn oil, vegetable oil, sesame oil, Olive oil, sunflower oil, palm kernel oil, soy sauce, jojoba oil, macadamia nut oil, soy sauce and the like can be mentioned. These may be used alone or in combination of two or more. Among them, a process oil is preferable, and an aromatic process oil is more preferable, because the effect of the present invention can be obtained well.

When the oil is contained, the content of the oil is preferably 1 part by mass or more, preferably 30 parts by mass or less, more preferably 12 parts by mass or less, more preferably 100 parts by mass of the rubber component. It is 5 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain a wax.
The wax is not particularly limited, and petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant waxes and animal waxes; and synthetic waxes such as polymers of ethylene and propylene. These may be used alone or in combination of two or more. Among them, petroleum waxes are preferable, and paraffin waxes are more preferable.

As the wax, for example, products such as Ouchi Emerging Chemical Industry Co., Ltd., Nippon Seiwa Co., Ltd., Seiko Kagaku Co., Ltd. can be used.

When the wax is contained, the content of the wax is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, with respect to 100 parts by mass of the rubber component, from the viewpoint of the balance of performance. Preferably it is 20 mass parts or less, More preferably, it is 10 mass parts or less. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain an antiaging agent.
Examples of the antiaging agent include naphthylamine antiaging agents such as phenyl-α-naphthylamine; diphenylamine antiaging agents such as octylated diphenylamine and 4,4′-bis (α, α′-dimethylbenzyl) diphenylamine; N -Isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, N, N'-di-2-naphthyl-p-phenylenediamine, etc. P-phenylenediamine antidegradants; quinoline antidegradants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; 2,6-di-t-butyl-4-methylphenol, Monophenolic anti-aging agents such as styrenated phenols; tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-] '- hydroxyphenyl) propionate] bis methane, tris, and the like polyphenolic antioxidants. These may be used alone or in combination of two or more. Among them, p-phenylenediamine based antioxidants and quinoline based antioxidants are preferred.

As an anti-aging agent, for example, products of SEIKO CHEMICAL Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Co., Ltd., etc. can be used.

When the antiaging agent is contained, the content of the antiaging agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. It is preferably at most 5 parts by mass, and more preferably at most 5 parts by mass. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain stearic acid.
As stearic acid, conventionally known ones can be used. For example, products such as NOF Corporation, NOF Company, Kao Corporation, Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Corporation can be used.

When stearic acid is contained, the content of stearic acid is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. And more preferably 5 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain zinc oxide.
As zinc oxide, conventionally known ones can be used, and for example, products such as Mitsui Metal Mining Co., Ltd., Toho Zinc Co., Ltd., Huxsui Tech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. Can be used.

When zinc oxide is contained, the content of zinc oxide is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. And more preferably 5 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain sulfur.
Sulfur includes powdery sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur and the like generally used in the rubber industry. These may be used alone or in combination of two or more.

As sulfur, for example, products such as Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Japan Co., Ltd., Nippon Hyoryu Kogyo Co., Ltd., Hosoi Kagaku Kogyo Co., Ltd. can be used.

When sulfur is contained, the content of sulfur is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 10 parts by mass or less, per 100 parts by mass of the rubber component. More preferably, it is 5 parts by mass or less, more preferably 3 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained better.

The rubber composition may contain a vulcanization accelerator.
As a vulcanization accelerator, thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram disulfide (TMTD Thiuram-based vulcanization accelerators such as tetrabenzylthiuram disulfide (TBzTD), tetrakis (2-ethylhexyl) thiuram disulfide (TOT-N), etc .; N-cyclohexyl-2-benzothiazolesulfenamide, N-t-butyl- 2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide, etc. Of Sulfena De-based vulcanization accelerator; diphenylguanidine, it may be mentioned di-ortho-tolyl guanidine, guanidine-based vulcanization accelerators such as ortho tri ruby guanidine. These may be used alone or in combination of two or more. Among these, sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators are preferable because the effects of the present invention are more suitably obtained.

When the vulcanization accelerator is contained, the content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. It is preferably at most 7 parts by mass, and more preferably at most 7 parts by mass. Within the above range, the effects of the present invention tend to be obtained better.

In the rubber composition, in addition to the above components, additives generally used in the tire industry, for example, organic peroxides; fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica and the like And the like may be further blended. The content of these fillers is preferably 0.1 to 200 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition can be produced, for example, by kneading the above-mentioned components using a rubber kneading apparatus such as an open roll or a Banbury mixer, and then vulcanizing.

The above rubber composition can be used for each component of a tire, but among them, it can be suitably used for a tread, a base tread, a sidewall, a carcass, a clinch and the like, and can be more suitably used for a tread (cap tread).

(Pneumatic tire)
The pneumatic tire of the present invention is manufactured in the usual manner using the above rubber composition.
That is, the rubber composition containing the above-mentioned components is extruded in an unvulcanized stage according to the shape of each tire member such as a tread, and is molded in the usual manner on a tire molding machine together with other tire members. As a result, an unvulcanized tire is formed. The unvulcanized tire is heated and pressurized in a vulcanizer to obtain a tire.

The pneumatic tire can be suitably used for a studless tire (winter tire), an all-season tire and the like which require excellent on-ice performance.

Although the present invention will be specifically described based on examples, the present invention is not limited to these.

The various medicines used by the example and the comparative example are summarized and explained.
NR: TSR20
BR: BR 150B (cis content: 98% by mass) manufactured by Ube Industries, Ltd.
Farnesene-based polymer 1: FB-823 (farnesene-butadiene copolymer, Mw: 50,000 based on Kuraray Co., Ltd., copolymerization ratio on a mass basis: farnesene / butadiene = 80/20, melt viscosity: 13 Pa · s, Tg = -78 ° C)
Farnesene-based polymer 2: FSR-221 (farnesene-styrene copolymer, Mw: 10000, copolymer ratio on a mass basis: Farnesene / styrene = 77/23, melt viscosity: 5.7 Pa · s, manufactured by Kuraray Co., Ltd.) Tg: -54 ° C)
Farnesene-based polymer 3: KB-101 (farnesene homopolymer, Mw: 10000, melt viscosity: 0.7 Pa · s, Tg: −72 ° C.) manufactured by Kuraray Co., Ltd.
Oil: Process P-200 made by Japan Energy Co., Ltd.
Eggshell flour 1: Eggshell flour (average particle size: 100 μm) manufactured by Green Techno 21 Co., Ltd.
Eggshell flour 2: Eggshell flour (average particle size: 250 μm) manufactured by Green Techno 21 Co., Ltd.
Carbon black: Diamond black N220 (N ₂ SA: 114 m ² / g) manufactured by Mitsubishi Chemical Corporation
Wax: Nippon Seiwa Co., Ltd. Ozo Ace 0355
Anti-aging agent: Noclac 6C (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine) manufactured by Ouchi Emerging Chemical Industry Co., Ltd.
Stearic acid: Beads made by NOF Corporation made with zinc stearate, zinc oxide: Zinc oxide from Mitsui Metal Mining Co., Ltd. Two types of sulfur: Powdered sulfur from Tsurumi Chemical Industry Co., Ltd. (containing 5% oil)
Vulcanization accelerator: Noccellar NS (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinko Chemical Co., Ltd.

(Example and Comparative Example)
Materials other than sulfur and a vulcanization accelerator were kneaded for 5 minutes under the condition of 150 ° C. using a Banbury mixer manufactured by Kobe Steel, Ltd. according to the contents of the formulation shown in Table 1 to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded using an open roll for 5 minutes at 80 ° C. to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition is molded into the shape of a tread, and is bonded together with other tire members to form an unvulcanized tire, which is press vulcanized under conditions of 170 ° C. for 10 minutes to obtain a test tire ( Size: 195 / 65R15) was manufactured. The evaluation shown below was performed using the obtained test tire, and the results are shown in Table 1.

(Performance on ice)
Each test tire is mounted on a domestic FF car, and after standing still on ice (0 ° C), the accelerator is fully opened, and the time taken to travel 50 m (acceleration time) is measured. It was displayed as the index when it was done (performance index on ice). The larger the index, the shorter the acceleration time, and the better the performance on ice (starting performance on ice).
In addition, after each tire for test was thermally deteriorated in an oven at 100 ° C for 7 days, the same measurement as described above was performed, and it was indicated as an index when Comparative Example 1 was set to 100 (performance index on ice (after deterioration)) . The larger the index, the better the performance on ice during aging.

From Table 1, in the examples, a synergistic improvement effect is obtained by using farnesene-based polymer and eggshell powder in combination, and the performance on ice is good in both initial and after deterioration, and is good over a long period of time It was confirmed that the performance on ice was exhibited.

Claims (7)

A rubber composition for a tire comprising a rubber component, a farnesene-based polymer and eggshell powder. The rubber composition for a tire according to claim 1, wherein the farnesene polymer is a liquid farnesene polymer. The rubber composition for a tire according to claim 1 or 2, wherein the farnesene-based polymer is a copolymer of farnesene and butadiene. The rubber composition for a tire according to any one of claims 1 to 3, wherein an average particle size of the eggshell powder is 250 μm or less. The rubber composition for a tire according to any one of claims 1 to 4, wherein the content of isoprene-based rubber is 30% by mass or more and the content of butadiene rubber is 30% by mass or more in 100% by mass of the rubber component. The pneumatic tire which has a tread produced using the rubber composition in any one of Claims 1-5. The pneumatic tire according to claim 6, which is a studless tire or an all season tire.