JP2021080473A - Rubber composition for tires, and tire - Google Patents

Abstract

To provide a rubber composition for tires which is excellent in performance of suppressing aged deterioration in fuel economy and wear resistance, and to provide a pneumatic tire.SOLUTION: The rubber composition for tires contains a rubber component in which the total content of styrene-butadiene rubber and polybutadiene is 90 mass% or more, a filler, and a vulcanizer. When a butadiene moiety of the styrene-butadiene rubber and the polybutadiene are taken together, the vinyl content is 53 mol% or more with respect to 100 mol% of the content of constituent units based on butadiene in the whole rubber composition.SELECTED DRAWING: None

Description

The present invention relates to a rubber composition for a tire and a tire.

Tires are required to have improved fuel efficiency.
For example, Patent Document 1 discloses a rubber composition capable of improving fuel efficiency by containing a predetermined amount of two predetermined types of silica.

Japanese Unexamined Patent Publication No. 2008-50570

As a result of diligent studies, the present inventor has found that there is room for improvement in suppressing aging deterioration of fuel efficiency and wear resistance with the conventional technology.
An object of the present invention is to solve the new problems found by the present inventor and to provide a rubber composition for a tire and a pneumatic tire having excellent fuel efficiency and wear resistance and aged deterioration suppressing performance.

The present invention is a rubber composition containing a rubber component having a total content of styrene-butadiene rubber and polybutadiene of 90% by mass or more, a filler, and a vulcanizing agent.
When the butadiene portion of styrene-butadiene rubber and polybutadiene are viewed together, the rubber composition for tires has a vinyl content of 53 mol% or more, where the content of the structural unit based on butadiene is 100 mol% in the entire rubber composition. Regarding things.

The amount of vinyl is preferably 55 mol% or more, more preferably 60 mol% or more, further preferably 65 mol% or more, and particularly preferably 70 mol% or more.

The rubber composition preferably contains 80 parts by mass or more of silica with respect to 100 parts by mass of the rubber component.

The rubber composition preferably contains styrene-butadiene rubber and polybutadiene.

The rubber composition preferably contains syndiotactic-1,1,2-polybutadiene.

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

According to the present invention, a rubber composition containing a rubber component having a total content of styrene-butadiene rubber and polybutadiene of 90% by mass or more, a filler, and a sulfide, and the butadiene portion of the styrene-butadiene rubber. When viewed together with polybutadiene, it is a rubber composition for tires in which the content of the constituent unit based on butadiene is 100 mol% and the vinyl content is 53 mol% or more in the entire rubber composition, so that the fuel efficiency is low. It has excellent aging deterioration suppression performance in terms of resistance and abrasion resistance.

The rubber composition for a tire of the present invention is a rubber composition containing a rubber component having a total content of styrene-butadiene rubber and polybutadiene of 90% by mass or more, a filler, and a vulcanizing agent.
When the butadiene portion of the styrene-butadiene rubber and the polybutadiene are viewed together, the content of the structural unit based on butadiene is 100 mol% and the vinyl content is 53 mol% or more in the entire rubber composition. As a result, it is possible to improve the fuel-efficient aging deterioration suppressing performance and the wear resistance aging deterioration suppressing performance.

The above-mentioned rubber composition for tires can obtain the above-mentioned effects, but the reason why such effects are obtained is not always clear, but it is presumed as follows.
The rubber composition for tires contains a rubber component mainly composed of styrene-butadiene rubber (SBR) and polybutadiene (BR), and when the butadiene portion of styrene-butadiene rubber and polybutadiene are viewed together, the entire rubber composition The content of the structural unit based on butadiene is 100 mol%, and the vinyl content (hereinafter, also referred to as the vinyl content of the rubber composition) is 53 mol% or more.
Here, as the structural unit based on butadiene, there are a cis-1,4 bond unit, a trans-1,4 bond unit, and a vinyl-1,2 bond unit. The cis-1,4 bond unit and the trans-1,4 bond unit have a double bond in the main chain, while the vinyl-1,2 bond unit does not have a double bond in the main chain.
The vinyl content of the rubber composition means the content of vinyl-1,2 bond units when the total content of the structural units based on styrene-butadiene rubber and butadiene derived from polybutadiene is 100 mol%, which will be described later. The trans amount of the rubber composition to be used means the content of trans-1,4 bond units when the total content of the structural units based on styrene-butadiene rubber and polybutadiene-derived butadiene is 100 mol%, and is described later. The cis content of the composition means the content of cis-1,4 bond units when the total content of the structural units based on styrene-butadiene rubber and butadiene derived from polybutadiene is 100 mol%.
By setting the vinyl content of the rubber composition to 53 mol% or more, the amount of double bonds in the polymer main chain is reduced, the probability that the polymer molecular chain is cut by ozone attack is reduced, and fuel efficiency and resistance are reduced. Aged deterioration of wear resistance can be suppressed.
As described above, the rubber composition for tires contains a rubber component mainly composed of styrene-butadiene rubber and polybutadiene, and by setting the vinyl content of the rubber composition to 53 mol% or more, fuel-efficient deterioration over time It is possible to improve the suppression performance and the aging deterioration suppression performance of wear resistance.
In addition, since the amount of vinyl is high, there are abundant sites in the polymer chain that can be bonded to the silane coupling agent, and the unreaction rate of the silica-coupling agent-polymer can be suppressed. Therefore, fuel efficiency and wear resistance can be further improved.

When the butadiene portion of styrene butadiene rubber and polybutadiene are viewed together, the above rubber composition for tires has a vinyl content (rubber composition) in which the content of the structural unit based on butadiene is 100 mol% in the entire rubber composition. The amount of vinyl in the product) is 53 mol% or more, preferably 55 mol% or more, more preferably 60 mol% or more, still more preferably 65 mol% or more, particularly preferably 70 mol% or more, and most preferably 73 mol%. As mentioned above, it is more preferably 75 mol% or more, preferably 90 mol% or less, and more preferably 85 mol% or less. When it is within the above range, the effect can be obtained more preferably.

When the butadiene portion of styrene butadiene rubber and polybutadiene are viewed together, the above rubber composition for tires has a trans amount (rubber composition) with the content of the structural unit based on butadiene as 100 mol% in the entire rubber composition. The amount of trans of the substance) is preferably 5 mol% or more, more preferably 10 mol% or more, further preferably 15 mol% or more, preferably 80 mol% or less, more preferably 75 mol% or less, still more preferably. It is 40 mol% or less, particularly preferably 35 mol% or less, and most preferably 30 mol% or less. When it is within the above range, the effect can be obtained more preferably.

When the butadiene portion of styrene-butadiene rubber and polybutadiene are viewed together, the above rubber composition for tires has a cis amount (rubber composition) with the content of the structural unit based on butadiene as 100 mol% in the entire rubber composition. The cis amount of the substance) is preferably 3 mol% or more, more preferably 5 mol% or more, further preferably 7 mol% or more, preferably 40 mol% or less, more preferably 35 mol% or less, still more preferably. It is 30 mol% or less, particularly preferably 20 mol% or less. When it is within the above range, the effect can be obtained more preferably.

The amount of vinyl in the rubber composition, the amount of trans in the rubber composition, and the amount of cis in the rubber composition can be achieved by appropriately combining SBR and BR to be used.
For example, an SBR having a large amount of vinyl, a BR having a large amount of transformer, a BR having a large amount of vinyl, and the like may be combined.

Hereinafter, the chemicals that can be used in the rubber composition will be described.

The rubber composition for a tire contains styrene-butadiene rubber (SBR) and / or polybutadiene (BR), but preferably contains SBR and BR because the effect can be obtained more preferably.

The SBR is not particularly limited, and for example, emulsion polymerization SBR (E-SBR), solution polymerization SBR (S-SBR), and the like, which are common in the tire industry, can be used. These may be used alone or in combination of two or more.

The amount of styrene in SBR is preferably 10% by mass or more, more preferably 15% by mass or more, further preferably 20% by mass or more, particularly preferably 25% by mass or more, and preferably 50% by mass or less, more preferably. Is 40% by mass or less, more preferably 35% by mass or less, and particularly preferably 30% by mass or less. Within the above range, the effect tends to be more preferably obtained.

The vinyl content of SBR is preferably 30 mol% or more, more preferably 35 mol% or more, further preferably 40 mol% or more, particularly preferably 50 mol% or more, most preferably 60 mol% or more, and more preferably 65. It is mol% or more, preferably 80 mol% or less, and more preferably 75 mol% or less. Within the above range, the effect tends to be more preferably obtained.
By using SBR having a vinyl amount within the above range (large amount), abundant sites that can be bonded to the silane coupling agent are present in the polymer chain, and the unreacted rate of the silica-coupling agent-polymer can be suppressed. Can be done. Therefore, fuel efficiency and wear resistance can be further improved.

The trans amount of SBR is preferably 5 mol% or more, more preferably 10 mol% or more, further preferably 15 mol% or more, and preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably. Is 60 mol% or less, particularly preferably 55 mol% or less, most preferably 40 mol% or less, more preferably 30 mol% or less, still most preferably 25 mol% or less. Within the above range, the effect tends to be more preferably obtained.

The cis amount of SBR is preferably 3 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, and preferably 40 mol% or less, more preferably 30 mol% or less, still more preferably. Is 25 mol% or less, particularly preferably 20 mol% or less. Within the above range, the effect tends to be more preferably obtained.

In the present specification, the vinyl amount, the trans amount, and the cis amount of the SBR mean the amounts when the content of the butadiene-based structural unit contained in the SBR is 100 mol%, respectively.

The SBR may be a non-modified SBR or a modified SBR.
The modified SBR may be any SBR having a functional group that interacts with a filler such as silica. For example, at least one end of the SBR is modified with a compound having the above functional group (modifying agent). SBR (terminal modified SBR having the functional group at the end), main chain modified SBR having the functional group in the main chain, and main chain terminal modified SBR having the functional group at the main chain and the terminal (for example, in the main chain) Main chain terminal modified SBR having the above functional group and having at least one end modified with the above modifying agent) or a polyfunctional compound having two or more epoxy groups in the molecule, which is modified (coupling) with a hydroxyl group. And terminally modified SBR into which an epoxy group has been introduced. These may be used alone or in combination of two or more.

Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group and a disulfide. Examples thereof include a group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group and an epoxy group. .. In addition, these functional groups may have a substituent. Among them, an amino group (preferably an amino group in which the hydrogen atom of the amino group is replaced with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), and an alkoxysilyl group (preferably an alkoxy group having 1 to 6 carbon atoms). Alkoxysilyl groups having 1 to 6 carbon atoms) and amide groups are preferable.

As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Co., Ltd., Asahi Kasei Co., Ltd., Zeon Corporation, etc. can be used.

The content of SBR in 100% by mass of the rubber component is 10% by mass or more, preferably 20% by mass or more, more preferably 40% by mass or more, still more preferably 60% by mass or more, and particularly preferably 70% by mass or more. It may be 100% by mass or less, but preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. Within the above range, the effect tends to be better obtained.

The polybutadiene (BR) is not particularly limited, and general ones in the tire industry can be used. For example, a high cis content high cis BR, a low cis content low cis BR, a BR containing syndiotactic polybutadiene crystals, a rare earth element, etc. BR (rare earth BR) synthesized by using a catalyst can be used. In addition, crystalline BR such as syndiotactic-1,2-polybutadiene can also be used. These may be used alone or in combination of two or more.

Further, the BR may be a non-modified BR or a modified BR. Examples of the modified BR include modified BRs into which the above-mentioned functional groups have been introduced. The preferred embodiment is the same as for the modified SBR.

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

Among them, BR1 and syndiotactic-1 / 2-polybutadiene (BR2) having a trans amount of 45 mol% or more are preferable, and syndiotactic-1 / 2-polybutadiene (BR2) is more preferable. Further, it is also preferable to use BR1 having a trans amount of 45 mol% or more in combination with syndiotactic-1,2-polybutadiene (BR2).
In particular, by blending syndiotactic-1,2-polybutadiene, the amount of double bonds in the polymer main chain is reduced, the probability that the polymer molecular chain is cut by ozone attack is reduced, and fuel efficiency and resistance are reduced. Aged deterioration of wear resistance can be more preferably suppressed. Conventionally, a BR containing a syndiotactic polybutadiene crystal (for example, VCR produced by Ube Industries, Ltd.) has also been used, but the main chain of the BR is a cis-1,4 bond, while the syndiotactic. In -1,2-polybutadiene (BR2), aged deterioration of fuel efficiency and wear resistance can be more preferably suppressed in that the main chain is a vinyl-1,2 bond.

The trans amount of BR1 is preferably 45 mol% or more, more preferably 50 mol% or more. The amount of trans is preferably 70 mol% or less, more preferably 60 mol% or less, still more preferably 55 mol% or less. Within the above range, the effect tends to be better obtained.

The vinyl content of BR1 is preferably 20 mol% or less, more preferably 15 mol% or less. The amount of vinyl is preferably 5 mol% or more, more preferably 10 mol% or more. Within the above range, the effect tends to be better obtained.

The cis amount of BR1 is preferably 20 mol% or more, more preferably 30 mol% or more. The amount of cis is preferably 50 mol% or less, more preferably 40 mol% or less. Within the above range, the effect tends to be better obtained.

The vinyl content of syndiotactic-1,2-polybutadiene (SPB, BR2) is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, and particularly preferably 93 mol% or more. Yes, it may be 100 mol%. Within the above range, the effect tends to be better obtained.

The trans amount and the cis amount of BR2 are preferably 6 mol% or less, more preferably 3 mol% or less, and may be 0 mol%, respectively. Within the above range, the effect tends to be better obtained.

The melting point of BR2 is not particularly limited, but is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 105 ° C. or higher, preferably 180 ° C. or lower, more preferably 150 ° C. or lower, still more preferably 130 ° C. or higher. It is as follows. Within the above range, the effect tends to be better obtained.
Here, in the present specification, the melting point of BR is the melting peak temperature of the DSC curve measured according to JIS K7121.

The crystallinity of BR2 is not particularly limited, but is preferably 15% or more, more preferably 25% or more, preferably 50% or less, and more preferably 40% or less. Within the above range, the effect tends to be better obtained.
Here, as for the crystallinity, the density of 1,2-polybutadiene having a crystallinity of 0% is 0.889 g / cm ³ , and the density of 1,2-polybutadiene having a crystallinity of 100% is 0. It is a value converted from the density measured by the underwater substitution method as 963 g / cm ^3.

The content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, particularly preferably 20% by mass or more, and preferably 20% by mass or more. It is 80% by mass or less, more preferably 60% by mass or less, still more preferably 40% by mass or less, and particularly preferably 30% by mass or less. Within the above range, the effect tends to be better obtained.

The content of BR1 in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 8% by mass or more, preferably 50% by mass or less, and more preferably 35% by mass or less. Within the above range, the effect tends to be better obtained.

The content of BR2 (SPB) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 8% by mass or more, preferably 50% by mass or less, and more preferably 35% by mass or less. .. Within the above range, the effect tends to be better obtained.

The total content of SBR and BR in 100% by mass of the rubber component is 90% by mass or more, preferably 95% by mass or more, more preferably 98% by mass or more, and may be 100% by mass. Within the above range, the effect tends to be better obtained.

Examples of rubber components that can be used in addition to SBR and BR include diene rubbers such as isoprene rubber, styrene isoprene butadiene rubber (SIBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR). Can be mentioned. The rubber component may be used alone or in combination of two or more. Of these, diene-based rubber is preferable, and isoprene-based rubber is more preferable.

Here, the rubber component preferably has a weight average molecular weight (Mw) of 150,000 or more, and more preferably 350,000 or more. The upper limit of Mw is not particularly limited, but is preferably 4 million or less, more preferably 3 million or less.

Examples of the isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR and the like. As the NR, for example, SIR20, RSS # 3, TSR20 and the like, which are common in the tire industry, can be used. The IR is not particularly limited, and for example, an IR 2200 or the like that is common in the tire industry can be used. Modified NR includes deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc., and modified NR includes epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. Examples of the modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, and the like. These may be used alone or in combination of two or more. Of these, NR is preferable.

In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are gel permeation chromatographs (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: It can be obtained by standard polystyrene conversion based on the measured value by TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation.
The amount of cis, the amount of vinyl, and the amount of trans ^{can be measured by 13} C-NMR measurement. The amount of styrene ^{can be measured by 1 1} H-NMR measurement.
The amount of vinyl in the rubber composition, the amount of trans in the rubber composition, and the amount of cis in the ^{rubber composition may be directly measured in the rubber composition by 13} C-NMR measurement, and the vinyl measured in the raw material rubber. It may be calculated from the amount, the amount of trans, and the amount of cis by proportional calculation according to the blending amount.

The rubber composition contains a filler (reinforcing filler).
The filler is not particularly limited, and examples thereof include silica, carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica. These may be used alone or in combination of two or more. Of these, silica and carbon black are preferable, and silica is more preferable. It is also preferable to use silica and carbon black together.

The content of the filler is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, still more preferably 60 parts by mass or more, and preferably 200 parts by mass or less, based on 100 parts by mass of the rubber component. It is more preferably 180 parts by mass or less, further preferably 160 parts by mass or less, particularly preferably 130 parts by mass or less, and most preferably 110 parts by mass or less. Within the above range, the effect tends to be better obtained.

The carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These may be used alone or in combination of two or more.

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, preferably 200 meters ² / g or less, more preferably 150 meters ² / g Below, it is more preferably 125 m ² / g or less. Within the above range, the effect tends to be better obtained.
In addition, in this specification, N ₂ SA of carbon black is a value measured according to JIS K6217-2: 2001.

As carbon black, for example, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nikka Carbon Co., Ltd., Columbia Carbon Co., Ltd., etc. Can be used.

The content of carbon black is preferably 3 parts by mass or more, preferably 80 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 30 parts by mass or less, based on 100 parts by mass of the rubber component. It is particularly preferably 20 parts by mass or less, and most preferably 10 parts by mass or less. Within the above range, the effect tends to be better obtained.

Examples of silica include dry silica (silicic anhydride) and wet silica (hydrous silicic acid), but wet silica is preferable because it contains a large amount of 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 40 m 2} / g or more, preferably 70 m ² / g or more, more preferably 80 m ² / g or more, still more preferably 140 m ² / g or more, and particularly preferably 160 m ² / G or more. The N ₂ SA is preferably 600 m ² / g or less, more preferably 300 m ² / g or less, ^{still more preferably 250 m 2} / g or less, and particularly preferably 200 m ² / g or less. Within the above range, the effect tends to be more preferably obtained.
The N ₂ SA of silica is a value measured by the BET method according to ASTM D3037-81.

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

The content of silica is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, particularly preferably 40 parts by mass or more, and most preferably 60 parts by mass with respect to 100 parts by mass of the rubber component. By mass or more, more preferably 80 parts by mass or more, further preferably 90 parts by mass or more, particularly preferably 100 parts by mass or more, and preferably 200 parts by mass or less, more preferably 180 parts by mass or less, still more preferably. It is 160 parts by mass or less, particularly preferably 140 parts by mass or less. Within the above range, the effect tends to be better obtained.

In the rubber composition, the content of silica in 100% by mass of the filler (reinforcing filler) is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 70% by mass or more, and particularly preferably. Is 85% by mass or more, most preferably 90% by mass or more, and may be 100% by mass. Within the above range, the effect tends to be more preferably obtained.

When the rubber composition contains silica, it is preferable to further contain a silane coupling agent.
The silane coupling agent is not particularly limited, and 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-trimethoxysilylethyl) ) Disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3- Sulfates such as triethoxysilylpropylmethacrylate monosulfide, mercaptos such as 3-mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane, vinyls such as vinyltriethoxysilane and vinyltrimethoxysilane, 3-amino Amino series such as propyltriethoxysilane and 3-aminopropyltrimethoxysilane, glycidoxy series such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, 3-nitropropyltrimethoxysilane, Examples thereof include nitro type such as 3-nitropropyltriethoxysilane and chloro type such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. As commercially available products, for example, products such as Degussa, Momentive, Shinetsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., Toray Dow Corning Co., Ltd. can be used. These may be used alone or in combination of two or more. Among them, a sulfide-based silane coupling agent is preferable, and a disulfide-based silane coupling agent having a disulfide bond such as bis (3-triethoxysilylpropyl) disulfide is more preferable, because the effect tends to be better obtained. ..

The content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 6 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, based on 100 parts by mass of silica. , More preferably 10 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition preferably contains sulfur as a cross-linking agent (vulcanizing agent).
Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur, which are generally used in the rubber industry. These may be used alone or in combination of two or more.
Examples of the vulcanizing agent other than sulfur include organic peroxides and the like.

As the sulfur, for example, products such as Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Corporation, Flexis Co., Ltd., Nippon Inui Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd. can be used.

The content of the vulcanizing agent (preferably sulfur) is preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more, still more preferably 0.3 part by mass or more with respect to 100 parts by mass of the rubber component. It is particularly preferably 0.5 parts by mass or more, preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 2 parts by mass or less, and particularly preferably 1.5 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition preferably contains a vulcanization accelerator.
Examples of the sulfide accelerator include thiazole-based sulfide-based sulfide accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiadylsulfenamide; tetramethylthiuram disulfide (TMTD). ), Tetrabenzyl thiuram disulfide (TBzTD), tetrakis (2-ethylhexyl) thiuram disulfide (TOT-N) and other thiuram-based sulfide accelerators; N-cyclohexyl-2-benzothiazolesulfenamide, N-t-butyl- 2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide, etc. Sulfenamide-based sulfide accelerator; guanidine-based sulfide accelerators such as diphenylguanidine, dioltotrilguanidine, orthotrilbiguanidine can be mentioned. These may be used alone or in combination of two or more. Of these, sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators are preferable, and the combined use of sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators is more preferable.

As the vulcanization accelerator, for example, products manufactured by Kawaguchi Chemical Industry Co., Ltd., Ouchi Shinko Chemical Co., Ltd., Line Chemie Co., Ltd., etc. can be used.

The content of the vulcanization accelerator is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still 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 less than or equal to parts by mass, more preferably 5 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain a resin.
The resin is not particularly limited, but for example, a solid alkylphenol resin, a styrene resin, a Kumaron inden resin, a terpene resin, a rosin resin, an acrylic resin, a dicyclopentadiene resin (DCPD resin), etc. Can be mentioned. These may be used alone or in combination of two or more.

Examples of the resin include Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Co., Ltd., Rutgers Chemicals Co., Ltd., BASF, Arizona Chemical Co., Ltd., Nikko Chemical Co., Ltd., Co., Ltd. Products such as Nippon Catalyst, JX Energy Co., Ltd., Arakawa Chemical Industry Co., Ltd., and Taoka Chemical Industry Co., Ltd. can be used.

The content of the resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more with respect to 100 parts by mass of the rubber component. The content is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, and further preferably 20 parts by mass or less.

The rubber composition may contain a softening agent.
The softening agent is not particularly limited, and examples thereof include oils and liquid diene-based polymers. These may be used alone or in combination of two or more.

Examples of the oil include process oils, vegetable oils and fats, or mixtures thereof. As the process oil, for example, a paraffin-based process oil, an aroma-based process oil, a naphthen-based process oil, or the like can be used. Vegetable oils and fats include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pineapple, tall oil, corn oil, rice oil, beni flower oil, sesame oil, Examples thereof include olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. These may be used alone or in combination of two or more. Of these, process oils are preferable, and aroma-based process oils are more preferable, because the effects can be obtained satisfactorily.

Examples of oils include Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., Ltd., H & R Co., Ltd., Toyokuni Seiyu Co., Ltd., Showa Shell Sekiyu Co., Ltd. And other products can be used.

The liquid diene polymer is a diene polymer in a liquid state at room temperature (25 ° C.).
The weight average molecular weight of the liquid diene polymer (Mw) of preferably 3.0 × 10 ³ or more, more preferably 4.0 × 10 ³ or more, preferably 1.0 × 10 ⁵ or less, more preferably 1.5 × is 10 ⁴ or less. When it is within the above range, the effect can be obtained more preferably.

Examples of the liquid diene polymer include a liquid styrene-butadiene copolymer (liquid SBR), a liquid butadiene polymer (liquid BR), a liquid isoprene polymer (liquid IR), and a liquid styrene isoprene copolymer (liquid SIR). Be done. These may be used alone or in combination of two or more. Of these, liquid SBR is preferable because the effect can be obtained more preferably.

As the liquid diene polymer, for example, products such as Sartmer Co., Ltd. and Kuraray Co., Ltd. can be used.

The content of the softener (preferably oil) is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, still more preferably 20 parts by mass or more, and particularly preferably 30 parts by mass with respect to 100 parts by mass of the rubber component. It is more than 80 parts by mass, more preferably 65 parts by mass or less, still more preferably 55 parts by mass or less. Within the above range, the effect tends to be better obtained. In addition, in this specification, the content of a softener also includes the amount of oil contained in rubber (oil spread rubber).

The rubber composition may contain wax.
The wax is not particularly limited, and examples thereof include petroleum wax such as paraffin wax and microcrystalline wax; natural wax such as plant wax and animal wax; and synthetic wax such as a polymer such as ethylene and propylene. These may be used alone or in combination of two or more. Of these, petroleum-based wax is preferable, and paraffin wax is more preferable.

As the wax, for example, products of Ouchi Shinko Kagaku Kogyo Co., Ltd., Nippon Seiro Co., Ltd., Seiko Kagaku Co., Ltd. and the like can be used.

The wax content is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 20 parts by mass or less, more preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. It is less than a part. Within the above range, the effect tends to be better obtained.

The rubber composition may contain an anti-aging agent.
Examples of the anti-aging agent include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging 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-based anti-aging agents; quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinolin; 2,6-di-t-butyl-4-methylphenol, Monophenolic anti-aging agents such as styrenated phenol; tetrakis- [methylene-3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] bis, tris, polyphenolic aging such as methane Preventive agents and the like can be mentioned. These may be used alone or in combination of two or more. Of these, p-phenylenediamine-based anti-aging agents and quinoline-based anti-aging agents are preferable, and p-phenylenediamine-based anti-aging agents and quinoline-based anti-aging agents are more preferable in combination.

As the anti-aging agent, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Co., Ltd. and the like can be used.

The content of the anti-aging agent 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, more preferably 5 parts by mass with respect to 100 parts by mass of the rubber component. It is less than a part. Within the above range, the effect tends to be better obtained.

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

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, more preferably 5 parts by mass with respect to 100 parts by mass of the rubber component. It is as follows. Within the above range, the effect tends to be better obtained.

The rubber composition may contain zinc oxide.
Conventionally known zinc oxide can be used. For example, products of Mitsui Metal Mining Co., Ltd., Toho Zinc Co., Ltd., HakusuiTech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. Can be used.

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, more preferably 5 parts by mass with respect to 100 parts by mass of the rubber component. It is as follows. Within the above range, the effect tends to be better obtained.

In addition to the above components, additives generally used in the tire industry may be further added to the rubber composition. The content of these additives 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 each of the components using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanizing.

As the kneading conditions, in the base kneading step of kneading additives other than the vulcanizing agent and the vulcanization accelerator, the kneading temperature is usually 100 to 180 ° C., preferably 120 to 170 ° C. In the final kneading step of kneading the vulcanizing agent and the vulcanization accelerator, the kneading temperature is usually 120 ° C. or lower, preferably 80 to 110 ° C. Further, the composition obtained by kneading the vulcanizing agent and the vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 140 to 190 ° C, preferably 150 to 185 ° C. The vulcanization time is usually 5 to 15 minutes.

The rubber composition includes, for example, tread (cap tread), sidewall, base tread, under tread, clinch, bead apex, breaker cushion rubber, carcass cord covering rubber, insulation, chafer, inner liner and the like. It can be used as a tire member (as a rubber composition for a tire) such as a side reinforcing layer of a run-flat tire. Among them, it is preferably used for treads.

The tire of the present invention (pneumatic tire, etc.) is produced by a usual method using the above rubber composition. That is, a rubber composition containing various additives as needed is extruded according to the shape of each member of the tire (particularly, tread (cap tread)) at the unvulcanized stage, and then put onto the tire molding machine. The tire can be manufactured by heating and pressurizing in a vulcanizer after forming an unvulcanized tire by molding it by a usual method and laminating it together with other tire members.

The tire is not particularly limited, and examples thereof include a pneumatic tire, a solid tire, and an airless tire. Of these, pneumatic tires are preferable.

The above tires are passenger car tires, large passenger car tires, large SUV tires, truck / bus tires, motorcycle tires, competition tires, studless tires (winter tires), all-season tires, run-flat tires, and aircraft tires. , Suitable for mining tires and the like.

The present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

Hereinafter, various chemicals used in Examples, Reference Examples, and Comparative Examples will be collectively described.
SBR1: Nipol NS616 manufactured by Nippon Zeon Corporation (styrene amount: 21% by mass, cis amount: 12 mol%, trans amount: 24 mol%, vinyl amount: 64 mol%)
SBR2: Modified SBR (styrene amount: 26% by mass, cis amount: 13 mol%, trans amount: 15 mol%, vinyl amount: 72 mol%, oil based on 100 parts by mass of rubber solid content) prepared in Production Example 1 below. (Contains 37.5 parts by mass)
BR1: Modified BR produced in Production Example 2 below (cis amount: 36 mol%, trans amount: 52 mol%, vinyl amount: 12 mol%, Mw: 550,000)
BR2: RB840 (Syndiotactic-1,2-polybutadiene, melting point: 126 ° C., cis amount: 3 mol%, trans amount: 3 mol%, vinyl amount: 94 mol%, crystallinity: manufactured by JSR Corporation 36%)
Carbon black: manufactured by Mitsubishi Chemical Corporation Seast _{I (N220, N 2 SA:} 114m 2 / g)
Silica: Evonik Degussa Uratosyl VN3 (N ₂ SA: 175m ² / g)
Stearic acid: Stearic acid "Camellia" manufactured by NOF CORPORATION
Wax: Ozo Ace 0355 manufactured by Nippon Seiro Co., Ltd.
Oil: Diana Process NH-70S (aroma process oil) manufactured by Idemitsu Kosan Co., Ltd.
Silane coupling agent: Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa
Zinc oxide: Zinc oxide type 2 anti-aging agent manufactured by Mitsui Mining & Smelting Co., Ltd .1: Nocrack 6C (N- (1,3-dimethylbutyl) -N'-phenyl-p manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. -Phenylylenediamine)
Anti-aging agent 2: Nocrack RD (Poly (2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
5% oil sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. (containing 5% oil)
Vulcanization accelerator CZ: Soxinol CZ (N-cyclohexyl-2-benzothiazolyl sulfeneamide) manufactured by Sumitomo Chemical Co., Ltd.
Vulcanization accelerator DPG: Soxinol D (N, N'-diphenylguanidine) manufactured by Sumitomo Chemical Co., Ltd.

(Manufacturing Example 1)
Cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene were charged into a nitrogen-substituted autoclave reactor. After adjusting the temperature of the contents of the reactor to 20 ° C., n-butyllithium was added to initiate polymerization. Polymerization was carried out under adiabatic conditions, and the maximum temperature reached 85 ° C. Butadiene was added when the polymerization conversion rate reached 99%, and after further polymerization for 5 minutes, methyltrimethoxysilane was added as a denaturant and the reaction was carried out for 15 minutes. After completion of the polymerization reaction, 2,6-di-tert-butyl-p-cresol was added. Next, 37.5 parts by mass of oil (Diana Process NH-70S) was added to 100 parts by mass of the obtained modified styrene-butadiene rubber, the solvent was removed by steam stripping, and the heat was adjusted to 110 ° C. It was dried by a roll to obtain a modified styrene-butadiene rubber (SBR2).

(Manufacturing Example 2)
In a nitrogen atmosphere, 3-dimethylaminopropyltrimethoxysilane was placed in a volumetric flask, and anhydrous hexane was further added to prepare a terminal modifier.
N-Hexane, butadiene, and TMEDA were added to a pressure-resistant container sufficiently substituted with nitrogen, and the temperature was raised to 60 ° C. Next, after adding butyllithium, the temperature was raised to 50 ° C. and the mixture was stirred for 3 hours. Next, the terminal denaturant was added and the mixture was stirred for 30 minutes. After adding methanol and 2,6-tert-butyl-p-cresol to the reaction solution, the reaction solution was placed in a stainless steel container containing methanol to recover the aggregates. The obtained aggregate was dried under reduced pressure for 24 hours to obtain a modified butadiene rubber (BR1).

(Examples, reference examples and comparative examples)
According to the compounding formula shown in Table 1 (the compounding amount of oil spread rubber indicates the compounding amount of rubber solid content), using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd., except for sulfur and vulcanization accelerator. The chemicals were kneaded under the condition of 150 ° C. for 4 minutes to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and the mixture was kneaded for 4 minutes under the condition of 80 ° C. using an open roll to obtain an unvulcanized rubber composition. Further, the obtained unvulcanized rubber composition was press-vulcanized at 170 ° C. for 12 minutes with a mold having a thickness of 0.5 mm to obtain a vulcanized rubber composition.
Further, the obtained unvulcanized rubber composition is formed into a tread shape and bonded together with other tire members to prepare an unvulcanized tire, which is press-vulcanized for 10 minutes under the condition of 170 ° C. for testing. Tires (size: 195 / 65R15) were obtained.

The obtained vulcanized rubber composition and test tire were allowed to stand in an oven at 40 ° C. for 60 days to obtain a vulcanized rubber composition and test tire after aging deterioration.

The following evaluations were carried out using the obtained vulcanized rubber composition (new), vulcanized rubber composition (after aging), test tire (new), and test tire (after aging). The results are shown in Table 1.

<Fuel efficiency>
A test piece for measurement was cut out from a rubber slab sheet (2 mm × 130 mm × 130 mm) made of the above vulcanized rubber composition, and a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.) was used at a temperature of 50 ° C. and an initial strain of 10. %, Dynamic strain 2%, and frequency 10 Hz, the tan δ of the test piece for measurement was measured, and the vulcanized rubber composition (new) of Reference Example 2 was taken as 100, and each vulcanized rubber composition was calculated by the following formula. The measurement result of the object was displayed as an index. The larger the index, the better the fuel efficiency.
(Fuel efficiency index) = (tan δ of the vulcanized rubber composition (new) of Reference Example 2) / (tan δ of each vulcanized rubber composition) × 100
Further, the fuel efficiency maintenance rate was calculated based on the evaluation results of each vulcanized rubber composition after new and aged deterioration. The larger the fuel efficiency maintenance rate, the better the fuel efficiency aging suppression performance. Here, when the fuel efficiency maintenance rate is 80 or more, it is determined that the vehicle has good fuel efficiency and aged deterioration suppressing performance.

<Abrasion resistance>
Each test tire (new) and test tire (after aging deterioration) are attached to a domestic FF vehicle, the groove depth of the tire tread after a mileage of 8000 km is measured, and running when the tire groove depth is reduced by 1 mm. The distance was calculated and displayed as an index when the reference comparison example was set to 100 (wear resistance index). The larger the index, the longer the mileage when the tire groove depth is reduced by 1 mm, and the better the wear resistance.
Furthermore, the wear resistance maintenance rate was calculated based on the evaluation results of each test tire, which was new and after aged deterioration. The larger the wear resistance maintenance rate, the better the wear resistance against aging deterioration. Here, when the wear resistance maintenance rate is 80 or more, it is determined that the wear resistance has good aging deterioration suppressing performance.

From Table 1, it is a rubber composition containing a rubber component having a total content of styrene-butadiene rubber and polybutadiene of 90% by mass or more, a filler, and a vulcanizing agent, and the butadiene portion and polybutadiene of the styrene-butadiene rubber. The examples and reference examples in which the content of the constituent unit based on butadiene is 100 mol% and the vinyl content is 53 mol% or more in the entire rubber composition are low fuel consumption and abrasion resistance. It was found that it is excellent in suppressing aging deterioration of sex.

Claims (11)

A rubber composition containing a rubber component having a total content of styrene-butadiene rubber and polybutadiene of 90% by mass or more, a filler, and a vulcanizing agent.
When the butadiene portion of styrene-butadiene rubber and polybutadiene are viewed together, the content of the structural unit based on butadiene is 100 mol% in the entire rubber composition, and the vinyl content is 58.2 mol% or more for tires. Rubber composition. The rubber composition for a tire according to claim 1, wherein the amount of vinyl is 59.9 mol% or more. The rubber composition for a tire according to claim 1, wherein the amount of vinyl is 60 mol% or more. The rubber composition for a tire according to claim 1, wherein the amount of vinyl is 65 mol% or more. The rubber composition for a tire according to claim 1, wherein the amount of vinyl is 70 mol% or more. When the butadiene portion of the styrene-butadiene rubber and the polybutadiene are viewed together, the trans amount is 5 to 35 mol% in the entire rubber composition, where the content of the structural unit based on butadiene is 100 mol%. The described rubber composition for tires. When the butadiene portion of the styrene-butadiene rubber and the polybutadiene are viewed together, the cis amount is 3 to 35 mol% in the entire rubber composition, where the content of the structural unit based on butadiene is 100 mol%. Or the rubber composition for tires according to 6. The rubber composition for a tire according to any one of claims 1 to 7, which contains 80 parts by mass or more of silica with respect to 100 parts by mass of the rubber component. The rubber composition for a tire according to any one of claims 1 to 8, which contains styrene-butadiene rubber and polybutadiene. The rubber composition for a tire according to any one of claims 1 to 9, which contains syndiotactic-1,2-polybutadiene. A tire having a tread using the rubber composition according to any one of claims 1 to 10.