JP2014095015A - Rubber composition for side wall, wing, base tread, side wall packing, breaker cushion or tie gum and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition capable of improving low fuel consumption of the rubber composition containing isoprene rubber and further providing good abrasion resistance, breaking elongation and workability, and to provide a pneumatic tire manufactured by using the rubber composition.SOLUTION: The invention relates to a rubber composition for a side wall, a wing, a base tread, a side wall packing, a breaker cushion or a tie gum, containing a rubber component, a carbon black having NSA of 20 to 90 m/g, sulfur and a compound represented by the formula (I), and having the content of the carbon black of 15 to 55 pts.mass and the content of the sulfur of 1.0 to 2.3 pts.mass based on 100 pts.mass of the rubber component, and the content of the compound represented by the formula (I) of 0.1 to 20 pts.mass based on 100 pts.mass of the carbon black.

Description

The present invention comprises a rubber composition for a sidewall, wing, base tread, sidewall packing, breaker cushion or tie gum, and a sidewall, wing, base tread, sidewall packing, breaker cushion and tie gum produced using the same. The present invention relates to a pneumatic tire having at least one selected from the group.

In recent years, there has been an increasing demand for low fuel consumption for automobiles, and it is desired to provide a rubber composition for tires that is excellent in low fuel consumption. As a method for improving fuel economy, a method of modifying styrene butadiene rubber or butadiene rubber and promoting dispersion of filler is known. For example, as a modified rubber for silica, an alkoxysilane having a nitrogen functional group is used. A terminal-modified butadiene rubber in which a terminal-modified rubber is coupled with tin has been proposed as a modified rubber for carbon black. Further, it is known that the silane coupling agent having a mercapto group described in Patent Document 1 has high reactivity with silica and has an effect of promoting dispersion of silica.

However, any of the above-described technologies for reducing fuel consumption is effective for styrene butadiene rubber and butadiene rubber, and isoprene rubbers such as natural rubber, highly purified natural rubber, isoprene rubber, and epoxidized natural rubber. On the other hand, the effect was not sufficient.

Usually, a rubber composition for tires is blended with styrene butadiene rubber or butadiene rubber and isoprene-based rubber. Particularly, in rubber compositions used for heavy-duty tires that require excellent rubber strength, isoprene-based rubber is mainly used. Rubber is compounded. Therefore, there is a demand for a technology for reducing fuel consumption that is effective for isoprene-based rubber.

JP 2012-122015 A

The present invention solves the above problems, improves the fuel efficiency of a rubber composition containing an isoprene-based rubber, and further provides sidewalls, wings, base treads, which can provide good wear resistance, elongation at break and workability. Rubber composition for side wall packing, breaker cushion or tie gum, and at least one selected from the group consisting of side wall, wing, base tread, side wall packing, breaker cushion and tie gum made using the rubber composition An object is to provide a pneumatic tire.

（式中、Ｒ^１、Ｒ^２は、同一又は異なって、水素原子、炭素数１〜２０のアルキル基、炭素数１〜２０のアルケニル基又は炭素数１〜２０のアルキニル基である。Ｍ^ｒ＋は金属イオンを示し、ｒはその価数を表す。） The present invention contains a rubber component, carbon black having a nitrogen adsorption specific surface area of 20 to 90 m ² / g, sulfur, and a compound represented by the following formula (I), and in 100% by mass of the rubber component, The isoprene-based rubber content is 40 to 75% by mass, the butadiene rubber content is 25 to 60% by mass, and the carbon black content is 15 to 55 parts by mass with respect to 100 parts by mass of the rubber component. A side wall in which the sulfur content is 1.0 to 2.3 parts by mass, and the content of the compound represented by the following formula (I) with respect to 100 parts by mass of the carbon black is 0.1 to 20 parts by mass. , Wing, base tread, sidewall packing, breaker cushion, or tie gum rubber composition.

^(Wherein, R 1, ^{R 2} are the same or different, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group or an alkynyl group having 1 to 20 carbon atoms having 1 to 20 carbon atoms ^{.M r +} Represents a metal ion, and r represents its valence.)

The compound represented by the formula (I) is preferably a compound represented by the following formula (I-1), (I-2) or (I-3).

The metal ion is preferably sodium ion, potassium ion or lithium ion.

The content of the compound represented by the formula (I) with respect to 100 parts by mass of the carbon black is preferably 0.5 to 5 parts by mass.

The carbon black preferably has a nitrogen adsorption specific surface area of 20 to 70 m ² / g, and the content of the carbon black with respect to 100 parts by mass of the rubber component is 15 to 50 parts by mass.

The butadiene rubber is at least one selected from the group consisting of a syndiotactic crystal-containing butadiene rubber, a rare earth butadiene rubber synthesized using a rare earth element catalyst, and a tin-modified butadiene rubber, and the rubber component is 100% by mass. Among them, the total content of the syndiotactic crystal-containing butadiene rubber, the rare earth butadiene rubber and the tin-modified butadiene rubber is preferably 10 to 60% by mass.

The present invention also relates to a pneumatic tire having at least one selected from the group consisting of sidewalls, wings, base treads, sidewall packings, breaker cushions and tie gums produced using the rubber composition.

According to the present invention, sidewalls, wings, base treads, and sidewall packings containing a predetermined amount of isoprene-based rubber, butadiene rubber, specific carbon black, sulfur, and a compound represented by the formula (I) Since it is a rubber composition for a breaker cushion or tie gum, it is possible to provide a pneumatic tire with improved fuel economy, wear resistance, elongation at break and workability in a well-balanced manner.

The rubber composition of the present invention contains isoprene-based rubber, butadiene rubber, specific carbon black, sulfur, and a compound represented by the formula (I). The compound represented by the formula (I) can be bonded to carbon black by the reaction of the terminal nitrogen functional group with a functional group such as a carboxyl group present on the surface of the carbon black, and the carbon-carbon double The bonding portion can be bonded to the polymer by a reaction with a polymer radical or a reaction involving sulfur crosslinking. Therefore, the dispersibility of carbon black can be improved and the good dispersion state can be maintained even during use. Further, since the polymer restrains the carbon black through the compound represented by the formula (I), the exothermic property can be suppressed. The compound represented by the formula (I) having these functions is blended with a butadiene rubber, a specific carbon black, and sulfur together with a rubber composition containing an isoprene-based rubber, thereby reducing the fuel consumption of the rubber composition. In addition, good wear resistance, elongation at break and workability can be obtained.

The rubber composition of the present invention contains isoprene-based rubber as a rubber component. In the isoprene-based rubber, a polymer chain is cut during kneading to generate radicals. The generated radical is captured by the compound represented by the formula (I), whereby the polymer chain and the compound represented by the formula (I) can be bonded.

Examples of the isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber (ENR), and high-purity natural rubber (HPNR), and NR can be preferably used.

The content of isoprene-based rubber in 100% by mass of the rubber component is 40% by mass or more, preferably 50% by mass or more. If it is less than 40% by mass, the fuel economy may not be sufficiently improved. The content of the isoprene-based rubber is 75% by mass or less, preferably 70% by mass or less. If it exceeds 75 mass%, sufficient wear resistance and crack growth resistance may not be ensured.

The rubber composition of the present invention contains butadiene rubber (BR) as a rubber component. Although it does not specifically limit as BR, Although what is common in a tire industry can be used, Syndiotactic crystal containing butadiene rubber (SPB containing BR), Rare earth type butadiene rubber (rare earth type) synthesize | combined using the rare earth element type catalyst. It is preferable to use at least one selected from the group consisting of BR) and tin-modified butadiene rubber (tin-modified BR), and it is more preferable to use rare earth BR. As the rare earth BR, those synthesized using a rare earth element catalyst and having a vinyl content of 1.0% by mass or less (preferably 0.8% by mass or less) and a cis content of 95% by mass or more can be suitably used. .
In the present invention, the vinyl content (1,2-bonded butadiene unit amount) and the cis content (cis-1,4-bonded butadiene unit amount) are values measured by infrared absorption spectrum analysis.

The total content of SPB-containing BR, rare earth BR and tin-modified BR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 30% by mass or more, and further preferably 35% by mass or more. If it is less than 10% by mass, sufficient wear resistance and crack growth resistance may not be ensured. The total content of SPB-containing BR, rare earth BR and tin-modified BR is preferably 60% by mass or less, more preferably 50% by mass or less. If it exceeds 60% by mass, the fuel economy may not be sufficiently improved.

The content of BR in 100% by mass of the rubber component is 25% by mass or more, preferably 30% by mass or more. If it is less than 25% by mass, sufficient abrasion resistance and crack growth resistance may not be ensured. The content of BR is 60% by mass or less, preferably 50% by mass or less. If it exceeds 60% by mass, the fuel economy may not be sufficiently improved.

The rubber composition of the present invention may use other rubber components in addition to isoprene-based rubber and BR. Other rubber components include diene rubbers such as styrene butadiene rubber (SBR), chloroprene rubber (CR), styrene isoprene butadiene rubber (SIBR), styrene isoprene rubber (SIR), and isoprene butadiene rubber. SBR is preferred because it is effective and Hs can be easily secured. As SBR, modified SBR for silica whose terminal is modified with aminoalkoxysilane can be suitably used.

When the rubber composition of this invention contains SBR, content of SBR in 100 mass% of rubber components becomes like this. Preferably it is 1-20 mass% or more, More preferably, it is 5-15 mass%.

The rubber composition of the present invention contains carbon black having a specific nitrogen adsorption specific surface area.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is 20 m ² / g or more, preferably 30 m ² / g or more, more preferably 35 m ² / g or more. If it is less than 20 m < ² > / g, there exists a possibility that sufficient abrasion resistance and breaking elongation cannot be ensured. The N ₂ SA of the carbon black is 90 m ² / g or less, preferably 70 m ² / g or less, more preferably 55 m ² / g or less. If it exceeds 90 m ² / g, the heat generated from carbon black is increased, and the reaction with the compound represented by formula (I) is less likely to proceed, so that the fuel economy may not be sufficiently improved. is there.

Carbon black dibutyl phthalate (DBP) oil absorption is preferably 65cm ^3/100 g or more, more preferably 80 cm ^3/100 g or more. If it is less than 65 cm < ³ > / 100g, there exists a possibility that sufficient Hs and breaking elongation cannot be ensured. DBP oil absorption of carbon black is preferably 120 cm ^3/100 g or less. Exceeds 120 cm ^3/100 g, it may not be possible to secure sufficient fuel economy.

The pH of carbon black is preferably 7.9 or less, more preferably 7.8 or less, still more preferably 7.7 or less, and particularly preferably 7.6 or less. If it exceeds 7.9, the amount of acidic functional groups of carbon black is small, so the reactivity (interaction) with the compound represented by formula (I) is small, and there is a possibility that fuel economy and the like cannot be improved sufficiently. is there. The pH of the carbon black is preferably 3.0 or more, more preferably 3.5 or more. If it is less than 3.0, the pH of the rubber composition is lowered, whereby the activity of the vulcanizing agent is lowered and the crosslinking efficiency tends to be lowered.

The volatile content of carbon black is preferably 0.8% by mass or more, more preferably 0.9% by mass or more, and further preferably 1.0% by mass or more. If it is less than 0.8% by mass, the reactivity (interaction) with the compound represented by the formula (I) becomes small, and there is a possibility that the fuel efficiency cannot be sufficiently improved. The volatile content of carbon black is preferably 3.5% by mass or less, more preferably 3.0% by mass or less. If it exceeds 3.5 mass%, it is necessary to volatilize most of the volatile components in the vulcanization process and continue vulcanization until porosity does not occur. There is a tendency to get worse.

In this specification, the DBP oil absorption, pH, and volatile content of carbon black are values measured by JIS K6221 (1982), and N ₂ SA of carbon black is a value measured by the method described by JIS K6217 (2001).

The content of carbon black is 15 parts by mass or more, preferably 25 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 15 parts by mass, sufficient Hs and elongation at break may not be ensured. The content of carbon black is 55 parts by mass or less, preferably 50 parts by mass or less, more preferably 45 parts by mass or less. If it exceeds 55 parts by mass, the heat build-up becomes too large, and there is a risk that the fuel efficiency and processability will deteriorate.

（式中、Ｒ^１、Ｒ^２は、同一又は異なって、水素原子、炭素数１〜２０のアルキル基、炭素数１〜２０のアルケニル基又は炭素数１〜２０のアルキニル基である。Ｍ^ｒ＋は金属イオンを示し、ｒはその価数を表す。） The rubber composition of the present invention contains a compound represented by the following formula (I).

^(Wherein, R 1, ^{R 2} are the same or different, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group or an alkynyl group having 1 to 20 carbon atoms having 1 to 20 carbon atoms ^{.M r +} Represents a metal ion, and r represents its valence.)

Examples of the alkyl group for R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group.
Examples of the alkenyl group for R ¹ and R ² include a vinyl group, an allyl group, a 1-propenyl group, and a 1-methylethenyl group.
Examples of the alkynyl group for R ¹ and R ² include an ethynyl group and a propargyl group.

R ¹ and R ² are preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and still more preferably a hydrogen atom. That is, the compound represented by the above formula (I) is preferably a compound represented by the following formula (I-1), (I-2) or (I-3). It is more preferable that it is a compound represented by.

In the above formulas (I), (I-1), (I-2), and (I-3), examples of metal ions include sodium ions, potassium ions, and lithium ions, and sodium ions are preferable.

Content of the compound represented by Formula (I) is 0.1 mass part or more with respect to 100 mass parts of carbon black, Preferably it is 0.5 mass part or more, More preferably, it is 1 mass part or more. If the amount is less than 0.1 parts by mass, fuel economy may not be sufficiently improved. Content of the compound represented by Formula (I) is 20 mass parts or less, Preferably it is 10 mass parts or less, More preferably, it is 5 mass parts or less. If the amount exceeds 20 parts by mass, processability such as Mooney viscosity, scorch resistance and extrusion processability may not be sufficiently secured.

The rubber composition of the present invention contains sulfur. It does not specifically limit as sulfur, A thing common in a tire industry can be used.

The content of sulfur is 1.0 part by mass or more, preferably 1.5 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 1.0 part by mass, the rubber composition may not be sufficiently vulcanized and the required rubber properties may not be obtained. The sulfur content is 2.3 parts by mass or less. If the amount exceeds 2.3 parts by mass, there is a risk of burning the rubber or causing oxidative deterioration during use.
The sulfur content is a total amount including a sulfur content derived from a sulfur-containing coupling agent such as DURALINK HTS manufactured by Flexis.

The rubber composition of the present invention preferably uses a C5 petroleum resin as an adhesion processing aid. The C5 petroleum resin is obtained by polymerizing a C5 (carbon number 5) petroleum hydrocarbon. C5 petroleum hydrocarbon refers to a C5 fraction (fraction having 5 carbon atoms) obtained by thermal decomposition of naphtha, and specifically, isoprene, 1,3-pentadiene, dicyclopentadiene, piperylene, etc. And diolefins such as 2-methyl-1-butene, 2-methyl-2-butene, and cyclopentene. The content of the C5 petroleum resin is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition of the present invention preferably uses a compound represented by the following formula (II) and / or a hydrate thereof as a crosslinking agent.
_{XO 3 S-S- (CH 2} ) q -S-SO 3 X (II)
(In the formula, q represents an integer of 3 to 10. X represents lithium, potassium, sodium, magnesium, calcium, barium, zinc, nickel, or cobalt.)

In formula (II), q is preferably an integer of 3 to 6. X is preferably potassium or sodium. Examples of the hydrate of the compound represented by the formula (II) include sodium salt monohydrate and sodium salt dihydrate. Preferably, 1,6-hexamethylene-dithiosulfuric acid is used. Sodium dihydrate.

When the rubber composition of the present invention contains a compound represented by the formula (II) and a hydrate thereof, the content thereof is preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the rubber component. More preferably, it is 0.5-3 mass parts.

In addition to the above components, the rubber composition of the present invention includes compounding agents generally used in the production of rubber compositions, such as reinforcing fillers such as silica, silane coupling agents, anti-aging agents, oils and waxes. Further, a vulcanization accelerator and the like can be appropriately blended.

The oil content is preferably 7 parts by mass or less, more preferably 4 parts by mass or less, and still more preferably 3 parts by mass or less with respect to 100 parts by mass of the rubber component. If it exceeds 7 parts by mass, the reaction between the compound represented by formula (I) and the functional group on the surface of carbon black may be inhibited. The lower limit of the oil content is not particularly limited, and may be 0 part by mass.

As a method for producing the rubber composition of the present invention, a known method, for example, a method of kneading each component with a known mixer such as a roll or Banbury can be used.

The rubber composition of the present invention can be used for tire sidewalls, wings, base treads, sidewall packings, breaker cushions or tie gums. The breaker cushion produced with the rubber composition of the present invention is suitable for passenger car tires.
The wing is a member arranged on both sides of the tread rubber, and specifically, a member shown in FIG. 1 of Japanese Patent Laid-Open No. 9-277801.
The base tread is an inner layer portion of a tread having a multilayer structure, and is an inner surface layer in a tread having a two-layer structure [a surface layer (cap tread) and an inner surface layer (base tread)].
The sidewall packing is also called a soft bead apex, and is a member extending in a tapered shape from the bead apex toward the outer side in the tire radial direction. Specifically, the side wall packing is shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2005-271857. It is a member.
The breaker cushion is a member provided between the edge portion of the breaker and the case (carcass), and specifically, a member shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2006-273934.
The tie gum is a member disposed between the case cord and the inner liner, and specifically, a member shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2010-095705.

The pneumatic tire of the present invention is produced by a usual method using the rubber composition. That is, if necessary, a rubber composition containing various additives is extruded in accordance with the shape of the tire sidewall, etc. at an unvulcanized stage, and molded on a tire molding machine by a normal method. Then, they are bonded together with other tire members to form an unvulcanized tire. This unvulcanized tire can be heated and pressurized in a vulcanizer to produce the pneumatic tire of the present invention.

The pneumatic tire of the present invention can be used for passenger car tires, heavy load tires and the like, and in particular, can be suitably used for heavy load tires containing a large amount of isoprene-based rubber.

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

Ｓ−（３−アミノプロピル）チオ硫酸：住友化学（株）製のＳ−（３−アミノプロピル）チオ硫酸（下記式で表される化合物）

カーボンブラック１：コロンビアカーボン社製のＳｔａｔｅｘ Ｎ５５０（Ｎ_２ＳＡ：４０ｍ^２／ｇ、ＤＢＰ吸油量：１１５ｃｍ^３／１００ｇ、ｐＨ：６．８、揮発分：１．８質量％）
カーボンブラック２：コロンビアカーボン社製のＳｔａｔｅｘ Ｎ６６０（Ｎ_２ＳＡ：３４ｍ^２／ｇ、ＤＢＰ吸油量：８２ｃｍ^３／１００ｇ、ｐＨ：７．７、揮発分：１．７質量％）
カーボンブラック３：コロンビアカーボン社製のＳｔａｔｅｘ Ｎ３３０（Ｎ_２ＳＡ：７８ｍ^２／ｇ、ＤＢＰ吸油量：１０２ｃｍ^３／１００ｇ、ｐＨ：７．４、揮発分：１．８質量％）
カーボンブラック４：コロンビアカーボン社製のＳｔａｔｅｘ Ｎ７６２（Ｎ_２ＳＡ：２９ｍ^２／ｇ、ＤＢＰ吸油量：６８ｃｍ^３／１００ｇ、ｐＨ：６．９、揮発分：１．０質量％）
カーボンブラック５：コロンビアカーボン社製のＳｔａｔｅｘ Ｎ２２０（Ｎ_２ＳＡ：１１４ｍ^２／ｇ、ＤＢＰ吸油量：１１４ｃｍ^３／１００ｇ、ｐＨ：７．５、揮発分：１．８質量％）
シリカ：エボニックデグッサ社製のＵ９０００Ｇｒ
シランカップリング剤：エボニックデグッサ社製のＳｉ７５
Ｃ５系石油樹脂：丸善石油化学（株）製のマルカレッツＴ−１００ＡＳ（軟化点：１０２℃）
ＴＤＡＥオイル：Ｈ＆Ｒ社製のＶｉｖａｔｅｃ
ワックス：日本精蝋（株）製のＯｚｏａｃｅ３５５
老化防止剤６ＰＰＤ：住友化学（株）性のアンチゲン６Ｃ
老化防止剤ＴＭＱ：大内新興化学工業（株）製のノクラック２２４
ステアリン酸：日油（株）製のステアリン酸 椿
酸化亜鉛：東邦亜鉛（株）製の銀嶺Ｒ
５％オイル含有粉末硫黄：細井化学工業（株）製のＨＫ−２００−５
加硫促進剤ＴＢＢＳ：大内新興化学工業（株）製のノクセラーＮＳ−Ｇ
ＨＴＳ：フレキシス社製のＤＵＲＡＬＩＮＫ ＨＴＳ（１，６−ヘキサメチレン−ジチオ硫酸ナトリウム・二水和物） Below, various chemical | medical agents used by the Example and the comparative example are demonstrated.
NR: TSR20
IR: IR2200
BR1: BUNA-CB25 manufactured by LANXESS (rare earth BR synthesized using Nd-based catalyst, vinyl content: 0.7% by mass: cis content: 97% by mass)
BR2: BUNA-CB22 manufactured by LANXESS (rare earth BR synthesized using Nd-based catalyst, vinyl content: 0.6% by mass: cis content: 97% by mass)
BR3: BR150B manufactured by Ube Industries, Ltd. (BR synthesized using a Co-based catalyst, cis content: 98% by mass)
BR4: VCR617 (SPB-containing BR, SPB content: 17% by mass) manufactured by Ube Industries, Ltd.
BR5: BR1250H (tin modified BR) manufactured by Nippon Zeon Co., Ltd.
SBR: HPR340 (modified SBR whose terminal is modified with aminoalkoxysilane) manufactured by JSR Corporation
Compound I: (2Z) -4-[(4-aminophenyl) amino] -4-oxo-2-butenoic acid sodium salt (compound represented by the following formula) manufactured by Sumitomo Chemical Co., Ltd.

S- (3-aminopropyl) thiosulfuric acid: S- (3-aminopropyl) thiosulfuric acid (compound represented by the following formula) manufactured by Sumitomo Chemical Co., Ltd.

Carbon black 1: Columbia Carbon Co. ^{_{Statex N550 (N 2 SA: 40m}} 2 / g, DBP oil ^absorption: 115cm 3 ^{/100g,pH:6.8,} volatile matter: 1.8 wt%)
Carbon black 2: Columbia Carbon Co. ^{_{Statex N660 (N 2 SA: 34m}} 2 / g, DBP oil ^absorption: 82cm 3 ^{/100g,pH:7.7,} volatile matter: 1.7 wt%)
Carbon black 3: Columbia Carbon Co. ^{_{Statex N330 (N 2 SA: 78m}} 2 / g, DBP oil ^absorption: 102cm 3 ^{/100g,pH:7.4,} volatile matter: 1.8 wt%)
Carbon black 4: Columbia Carbon Co. ^{_{Statex N762 (N 2 SA: 29m}} 2 / g, DBP oil ^absorption: 68cm 3 ^{/100g,pH:6.9,} volatile matter: 1.0 wt%)
Carbon black 5: Colombian Carbon Co. ^{_{Statex N220 (N 2 SA: 114m}} 2 / g, DBP oil ^absorption: 114cm 3 ^{/100g,pH:7.5,} volatile matter: 1.8 wt%)
Silica: U9000Gr manufactured by Evonik Degussa
Silane coupling agent: Si75 manufactured by Evonik Degussa
C5 petroleum resin: Marukaretsu T-100AS manufactured by Maruzen Petrochemical Co., Ltd. (softening point: 102 ° C.)
TDAE oil: Vivatec made by H & R
Wax: Ozoace 355 manufactured by Nippon Seiwa Co., Ltd.
Anti-aging agent 6PPD: Sumitomo Chemical Co., Ltd. Antigen 6C
Anti-aging agent TMQ: NOCRACK 224 manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Stearic acid: Stearic acid manufactured by NOF Corporation Zinc oxide: Silver candy R manufactured by Toho Zinc Co., Ltd.
Powder sulfur containing 5% oil: HK-200-5 manufactured by Hosoi Chemical Co., Ltd.
Vulcanization accelerator TBBS: Noxeller NS-G manufactured by Ouchi Shinsei Chemical Co., Ltd.
HTS: DURALINK HTS (sodium 1,6-hexamethylene-dithiosulfate dihydrate) manufactured by Flexis

(Examples and Comparative Examples)
(Base kneading process 1)
Using a 1.7L Banbury mixer manufactured by Kobe Steel Co., Ltd., 70 parts by mass of rubber component (priority for isoprene-based rubber), 30 parts by mass of carbon black (priority for N ₂ SA) and Compound I total amount The mixture was kneaded for 4 minutes and discharged at 150 ° C. to obtain a master batch. In addition, about Example 9, since the compounding quantity of carbon black is less than 30 mass parts, the whole quantity (25 mass parts) was thrown in at this process.
(Base kneading process 2)
To the obtained master batch, the remaining rubber component and carbon black, and materials other than sulfur, vulcanization accelerator and HTS are added, kneaded for 4 minutes with the Banbury mixer, and discharged at 150 ° C. A kneaded product was obtained.
(Finish kneading process)
Sulfur, a vulcanization accelerator and HTS were added to the obtained kneaded product, kneaded for 2 minutes with an open roll, and discharged at 105 ° C. to obtain an unvulcanized rubber composition.
(Vulcanization process)
The obtained unvulcanized rubber composition was press vulcanized at 150 ° C. for 30 minutes to obtain a vulcanized rubber composition.

The following evaluation was performed using the obtained unvulcanized rubber composition and vulcanized rubber composition. Each test result is shown in Tables 1 and 2.

(Viscoelasticity test)
Using a viscoelastic spectrometer VES manufactured by Iwamoto Seisakusho Co., Ltd., the complex elastic modulus E ^* of the above vulcanized rubber composition under the conditions of temperature 70 ° C., frequency 10 Hz, initial strain 10% and dynamic strain 2%. MPa) and loss tangent tan δ were measured. Larger E ^* indicates higher rigidity and better steering stability, and smaller tan δ indicates less heat generation and better fuel efficiency. Note that tan δ is also expressed as an index with tan δ of Comparative Example 1 being 100. A larger index indicates better fuel efficiency.

(Tensile test)
Using a No. 3 dumbbell-shaped test piece made of the above vulcanized rubber composition, a tensile test was conducted at room temperature in accordance with JIS K 6251 “Vulcanized rubber and thermoplastic rubber-Determination of tensile properties” The elongation EB (%) was measured. It shows that it is excellent in breaking elongation (durability), so that EB is large. In addition, EB was also expressed as an index with the EB of Comparative Example 1 as 100. It shows that it is excellent in elongation at break, so that an index | exponent is large.

(Abrasion resistance)
Using a LAT tester (Laboratory Abrasion and Skid Tester), the volume loss of each vulcanized rubber composition was measured under the conditions of a load of 75 N, a speed of 20 km / h, and a slip angle of 5 °. The amount is shown as an index with 100 as the value. It shows that it is excellent in abrasion resistance, so that an index | exponent is large.

(Processability)
Comparative Example 1 was evaluated by visual and tactile evaluation of the edge state, the degree of rubber burn, the degree of adhesion between rubbers, and the flatness of a molded product obtained by molding each unvulcanized rubber composition after extrusion into a predetermined sidewall shape. Is shown as an index with 100 being 100. It shows that it is excellent in workability (sheet workability), so that a numerical value is large.
As for the edge state, the state where the edge is straight and smooth is considered good, and the degree of burnt rubber is good when there is no unevenness due to Pitt's burnt rubber lump in a 15 cm square 2 mm sheet cut out from the molded product. As for the flatness, the state in which the sheet is flat and in close contact with the flat plate was evaluated as good.

From Tables 1 and 2, an example containing a predetermined amount of isoprene-based rubber, butadiene rubber, specific carbon black, sulfur, and a compound represented by the formula (I) is low fuel consumption and wear resistance. The elongation at break and workability were improved in a well-balanced manner. Steering stability was also good.

Claims (7)

Containing a rubber component, carbon black having a nitrogen adsorption specific surface area of 20 to 90 m ² / g, sulfur, and a compound represented by the following formula (I):
In 100% by mass of the rubber component, the content of isoprene-based rubber is 40 to 75% by mass, and the content of butadiene rubber is 25 to 60% by mass.
The content of the carbon black is 15 to 55 parts by mass and the sulfur content is 1.0 to 2.3 parts by mass with respect to 100 parts by mass of the rubber component.
A rubber composition for a sidewall, wing, base tread, sidewall packing, breaker cushion, or tie gum, wherein the content of the compound represented by the following formula (I) with respect to 100 parts by mass of the carbon black is 0.1 to 20 parts by mass. .

^(Wherein, R 1, ^{R 2} are the same or different, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group or an alkynyl group having 1 to 20 carbon atoms having 1 to 20 carbon atoms ^{.M r +} Represents a metal ion, and r represents its valence.) The sidewall, wing, base tread according to claim 1, wherein the compound represented by the formula (I) is a compound represented by the following formula (I-1), (I-2) or (I-3): Rubber composition for sidewall packing, breaker cushion or tie gum.

The rubber composition for a sidewall, wing, base tread, sidewall packing, breaker cushion, or tie gum according to claim 1 or 2, wherein the metal ion is sodium ion, potassium ion, or lithium ion. The side wall, wing, base tread, side according to any one of claims 1 to 3, wherein the content of the compound represented by the formula (I) with respect to 100 parts by mass of the carbon black is 0.5 to 5 parts by mass. Rubber composition for wall packing, breaker cushion or tie gum. The carbon black has a nitrogen adsorption specific surface area of 20 to 70 m ² / g,
The sidewall, wing, base tread, sidewall packing, breaker cushion, or rubber for tie gum according to any one of claims 1 to 4, wherein the carbon black content is 15 to 50 parts by mass with respect to 100 parts by mass of the rubber component. Composition. The butadiene rubber is at least one selected from the group consisting of a syndiotactic crystal-containing butadiene rubber, a rare earth butadiene rubber synthesized using a rare earth element catalyst, and a tin-modified butadiene rubber,
The total content of the syndiotactic crystal-containing butadiene rubber, the rare earth-based butadiene rubber and the tin-modified butadiene rubber is 10 to 60% by mass in 100% by mass of the rubber component. Rubber composition for side wall, wing, base tread, side wall packing, breaker cushion or tie gum. A pneumatic tire having at least one selected from the group consisting of a sidewall, a wing, a base tread, a sidewall packing, a breaker cushion, and a tie gum produced using the rubber composition according to claim 1.