JP2015157879A - Tire rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire rubber composition where colorfastness and tire appearance can be improved while good fuel efficiency, abrasion resistance, and on-ice performance are maintained or improved, and a pneumatic tire using the tire rubber composition.SOLUTION: The present invention relates to a tire rubber composition including 0.1-6.0 parts by mass of a nonionic surfactant represented by formula (1) and/or ester of the formula (1) with respect to 100 parts by mass of rubber components, and including sulfur and a total content of at least 70% by mass of butadiene rubber, natural rubber, and isoprene rubber in 100% by mass of rubber components. In the formula (1), Rrepresents a 6-26C hydrocarbon group and d represent any integer.

Description

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

Since an automobile tire uses a rubber composition made of natural rubber or a diene synthetic rubber as a raw material, cracks may occur due to the progress of deterioration in the presence of ozone. In order to suppress the occurrence and progress of cracks in the presence of ozone, for example, an antioxidant (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine (6PPD), poly (2 , 2,4-trimethyl-1,2-) dihydroquinoline (TMDQ), etc.) and additives such as petroleum waxes are blended in the rubber composition.

The anti-aging agent and petroleum wax act to protect rubber from ozone by shifting (blooming) from vulcanized rubber to the surface of rubber such as tires. However, excessive blooming of the anti-aging agent and petroleum wax in a short period of time causes white discoloration. Moreover, the anti-aging agent deteriorated by ozone causes tea discoloration. Similarly, excessive blooming causes brown discoloration. Further, when the wax or the like deposited on the tire surface is uneven, light irregular reflection occurs, making the brown discoloration due to the deteriorated anti-aging agent more noticeable, and the tire gloss is lost.

Patent Document 1 describes that deterioration of the appearance of a tire can be prevented by blending an ether type nonionic surfactant of polyoxyethylene. However, there is room for improvement in terms of improving discoloration resistance and the appearance of the tire while maintaining or improving good fuel efficiency, wear resistance, and performance on ice.

Japanese Patent Laid-Open No. 05-194790

The present invention solves the above-mentioned problems and uses a rubber composition for tires that can improve discoloration resistance and appearance of a tire while maintaining or improving good fuel economy, wear resistance, and performance on ice, and the same. An object is to provide a pneumatic tire.

（式（１）中、Ｒ^１は、炭素数６〜２６の炭化水素基を表す。ｄは任意の整数を表す。）

（式（２）中、Ｒ^２及びＲ^３は、同一若しくは異なって、炭素数６〜２６の炭化水素基を表す。ｅは任意の整数を表す。） The present invention includes 0.1 to 6.0 parts by mass of a nonionic surfactant represented by the following formula (1) and / or the following formula (2) with respect to 100 parts by mass of the rubber component, The total content of butadiene rubber, natural rubber, and isoprene rubber is 70% by mass or more, and relates to a tire rubber composition containing sulfur.

(In the formula (1), ^{R 1} is, .d representing a hydrocarbon group of 6 to 26 carbon atoms represents an arbitrary integer.)

(In formula (2), R ² and R ³ are the same or different and represent a hydrocarbon group having 6 to 26 carbon atoms. E represents an arbitrary integer.)

The tire rubber composition preferably contains 15 to 150 parts by mass of silica with respect to 100 parts by mass of the rubber component.

The tire rubber composition preferably has a styrene butadiene rubber content of 1 to 30% by mass in 100% by mass of the rubber component.

The tire rubber composition preferably contains 0.1 to 6.0 parts by mass of the sulfur with respect to 100 parts by mass of the rubber component.

The present invention also relates to a pneumatic tire having a tire member produced using the rubber composition.

The tire member is preferably a tread.

The pneumatic tire is preferably a winter tire.

According to the present invention, the rubber component contains 0.1 to 6.0 parts by mass of the nonionic surfactant represented by the above formula (1) and / or the above formula (2) with respect to 100 parts by mass of the rubber component. Since the total content of butadiene rubber, natural rubber, and isoprene rubber is 70% by mass or more in 100% by mass of the component, and it is a rubber composition for tires containing sulfur, good fuel economy, wear resistance, on ice While maintaining or improving the performance, discoloration resistance and appearance of the tire can be improved, and a pneumatic tire excellent in fuel efficiency, wear resistance, performance on ice, discoloration resistance, and tire appearance can be provided.

The tire rubber composition of the present invention contains 0.1 to 6.0 mass of the nonionic surfactant represented by the above formula (1) and / or the above formula (2) with respect to 100 parts by mass of the rubber component. The total content of butadiene rubber, natural rubber, and isoprene rubber is 70% by mass or more and contains sulfur in 100% by mass of the rubber component.

In the present invention, in a rubber composition in which a specific rubber component and sulfur are blended, the tire surface (bloom layer) unevenness formed by precipitation of wax or the like is blended by blending a specific nonionic surfactant. Smoothing is performed, and irregular reflection of light is suppressed. Thereby, discoloration resistance, such as reducing the above-mentioned brown discoloration and white discoloration, is also improved. In addition, the tire appearance is improved by giving the tire surface an appropriate black appearance and gloss. At the same time, good on-ice performance, low fuel consumption and wear resistance can be maintained or improved.

In addition, as described above, the above rubber composition maintains or improves on-ice performance, low fuel consumption, and wear resistance as a result of appropriate control of the compatibility between the rubber composition and the specific nonionic surfactant. However, it is speculated that the tire appearance can be improved.

（式（１）中、Ｒ^１は、炭素数６〜２６の炭化水素基を表す。ｄは任意の整数を表す。）

（式（２）中、Ｒ^２及びＲ^３は、同一若しくは異なって、炭素数６〜２６の炭化水素基を表す。ｅは任意の整数を表す。） In the present invention, a nonionic surfactant represented by the following formula (1) and / or the following formula (2) is used. A nonionic surfactant may be used independently and may use 2 or more types together. Among these, the nonionic surfactant represented by the following formula (1) is preferable because the effects of the present invention (particularly, low fuel consumption, abrasion resistance, performance on ice, and discoloration resistance) can be obtained more suitably. preferable.

(In formula (1), ^{R 1,} .d representing a hydrocarbon group of 6 to 26 carbon atoms represents an arbitrary integer.)

(In formula (2), R ² and R ³ are the same or different and represent a hydrocarbon group having 6 to 26 carbon atoms. E represents an arbitrary integer.)

R ^{1 in} Formula (1) represents a hydrocarbon group having 6 to 26 carbon atoms. When the carbon number of the hydrocarbon group of R ¹ is 5 or less, since the permeability to rubber is low and the speed of transfer to the rubber surface becomes too fast, the rubber surface tends to deteriorate in appearance. In addition, when the carbon number of the hydrocarbon group of R ¹ is 27 or more, the raw material is difficult to obtain or expensive and is not suitable. When the carbon number of the hydrocarbon group of R ¹ is within the above range, the bloom of the nonionic surfactant can be suitably controlled, and the effects of the present invention can be obtained more suitably.

The number of carbon atoms in the hydrocarbon group R ¹ is preferably 8 to 24, more preferably 10 to 22, more preferably from 14 to 20.

Examples of the hydrocarbon group having 6 to 26 carbon atoms of R ¹ include an alkenyl group having 6 to 26 carbon atoms, an alkynyl group having 6 to 26 carbon atoms, and an alkyl group having 6 to 26 carbon atoms.

Examples of the alkenyl group having 6 to 26 carbon atoms include 1-hexenyl group, 2-hexenyl group, 1-octenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, heptadecenyl group, octadecenyl group Group, icocenyl group, tricocenyl group, hexacocenyl group and the like.

Examples of the alkynyl group having 6 to 26 carbon atoms include hexynyl group, heptynyl group, octynyl group, noninyl group, decynyl group, undecynyl group, dodecynyl group, tridecynyl group, tetradecynyl group, pentadecynyl group, heptadecynyl group, octadecynyl group, Examples include an icosinyl group, a tricosinyl group, and a hexacosinyl group.

Examples of the alkyl group having 6 to 26 carbon atoms include hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, Examples include an octadecyl group, a heptadecyl group, an octadecyl group, an icosyl group, a tricosyl group, and a hexacosyl group.

R ¹ is preferably an alkenyl group having 6 to 26 carbon atoms and an alkynyl group having 6 to 26 carbon atoms, and more preferably an alkenyl group having 6 to 26 carbon atoms.

As d (integer) is larger, the HLB value representing the hydrophilic / lipophilic balance is higher, and the speed of transfer to the rubber surface tends to be higher. In the present invention, the value of d is not particularly limited, and can be appropriately selected according to use conditions and purposes. Especially, as d, Preferably it is 2-25, More preferably, it is 4-20, More preferably, it is 8-16, Most preferably, it is 10-14.

Examples of the nonionic surfactant represented by the above formula (1) include polyethylene glycol monooleate, polyethylene glycol monopalmitoleate, polyethylene glycol monovacenoate, polyethylene glycol monolinoleate, polyethylene glycol monolinolenate, polyethylene monoarachidonate. Glycol, ethylene glycol monooleate, ethylene glycol monopalmitate, ethylene glycol monopalmitate, ethylene glycol monopaxenate, ethylene glycol monolinoleate, ethylene glycol monolinolenate, ethylene glycol monoarachidonate, ethylene glycol monostearate, And ethylene glycol monocetylate. These may be used alone or in combination of two or more. Of these, polyethylene glycol monooleate, ethylene glycol monooleate, ethylene glycol monolaurate, ethylene glycol monostearate, and ethylene glycol monopalmitate are preferred because the effects of the present invention can be obtained more suitably.

R ² and R ^{3 in} the formula (2) are the same or different and represent a hydrocarbon group having 6 to 26 carbon atoms. When the carbon number of the hydrocarbon group of R ² and R ³ is 5 or less, the rubber permeability is low and the speed of transition to the rubber surface becomes too fast, so that the appearance of the rubber surface tends to deteriorate. Further, when the carbon number of the hydrocarbon group of R ² and R ³ is 27 or more, the raw material is difficult to obtain or expensive, and is inappropriate. When the carbon number of the hydrocarbon group of R ² and R ³ is within the above range, the bloom of the nonionic surfactant can be suitably controlled, and the effects of the present invention can be more suitably obtained.

Number of carbon atoms in the hydrocarbon group of R ² and ^{R 3} are preferably 8 to 24, more preferably 10 to 22, more preferably from 14 to 20.

Examples of the hydrocarbon group having 6 to 26 carbon atoms of R ² and R ³ include an alkenyl group having 6 to 26 carbon atoms, an alkynyl group having 6 to 26 carbon atoms, and an alkyl group having 6 to 26 carbon atoms.

Examples of the alkenyl group having 6 to 26 carbon atoms, the alkynyl group having 6 to 26 carbon atoms, and the alkyl group having 6 to 26 carbon atoms include the same groups as those described above for R ¹ .

The R ² and ^{R 3,} an alkenyl group having 6 to 26 carbon atoms, preferably an alkynyl group having 6 to 26 carbon atoms, more preferably an alkenyl group having 6 to 26 carbon atoms.

As e (integer) is larger, the HLB value representing the hydrophilic / lipophilic balance is higher, and the speed of moving to the rubber surface tends to be faster. In the present invention, the value of e is not particularly limited, and can be appropriately selected according to use conditions and purposes. Especially, as e, Preferably it is 2-25, More preferably, it is 4-20, More preferably, it is 8-16, Most preferably, it is 10-14.

Examples of the nonionic surfactant represented by the above formula (2) include polyethylene glycol dioleate, polyethylene glycol dipalmitoleate, polyethylene glycol dibactenoate, polyethylene glycol dilinoleate, polyethylene glycol dilinolenate, polyethylene glycol diarachidate, and ethylene glycol. Dioleate, ethylene glycol dipalmitate, ethylene glycol dipalmitate, ethylene glycol dipaxenate, ethylene glycol dilinoleate, ethylene glycol dilinolenate, ethylene glycol diarachidonate, ethylene glycol distearate, ethylene glycol dicetylate Etc. These may be used alone or in combination of two or more. Of these, polyethylene glycol dioleate, ethylene glycol dioleate, ethylene glycol dilaurate, ethylene glycol distearate, and ethylene glycol dipalmitate are preferred because the effects of the present invention can be obtained more suitably.

The content of the nonionic surfactant represented by the above formula (1) and / or the above formula (2) with respect to 100 parts by mass of the rubber component (preferably the nonionic surfactant represented by the above formula (1) The total content of the agent and the nonionic surfactant represented by the above formula (2) is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and further preferably 0.6 parts by mass. Part or more, particularly preferably 1 part by weight or more, and most preferably 1.2 parts by weight or more. If the amount is less than 0.1 parts by mass, the effects of the present invention may not be sufficiently obtained. The total content is preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, and still more preferably 4.0 parts by mass or less. If it exceeds 6.0 parts by mass, fuel economy, wear resistance, performance on ice, and tire appearance may be deteriorated.

In the rubber composition of the present invention, at least one rubber selected from the group consisting of butadiene rubber (BR), natural rubber (NR), and isoprene rubber (IR) is used. These may be used alone or in combination of two or more. Among these, NR and BR are preferable, and NR and BR are more preferably used in combination, because good fuel economy, wear resistance, and performance on ice can be more suitably obtained.

In the rubber composition, the total content of butadiene rubber, natural rubber and isoprene rubber (preferably the total content of butadiene rubber and natural rubber) is 70% by mass or more, preferably 80% by mass in 100% by mass of the rubber component. % Or more, and may be 100% by mass. If it is less than 70% by mass, good fuel economy, wear resistance, and performance on ice cannot be obtained sufficiently. Moreover, the ratio of butadiene rubber, natural rubber, and isoprene rubber can be freely designed as long as the reinforcing property, wear resistance, and performance on ice are not impaired.

As the NR, for example, those commonly used in the tire industry such as SIR20, RSS # 3, TSR20 and the like can be used. These may be used alone or in combination of two or more.

When the rubber composition contains NR, the content of NR in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more. The NR content is preferably 80% by mass or less, more preferably 70% by mass or less. When the content of NR is within the above range, good fuel economy, wear resistance, and performance on ice can be more suitably obtained.

The IR is not particularly limited, and those commonly used in the tire industry can be used. These may be used alone or in combination of two or more.

The BR is not particularly limited. For example, BR730, BR51 manufactured by JSR Corporation, BR1220 manufactured by Nippon Zeon Co., Ltd., BR130B manufactured by Ube Industries, Ltd., BR150B, BR710, etc. are used. it can. These may be used alone or in combination of two or more. 90% by mass or more is preferable, and 95% by mass or more is more preferable because good fuel efficiency, abrasion resistance, and performance on ice can be more suitably obtained.

When the said rubber composition contains BR, content of BR in 100 mass% of rubber components becomes like this. Preferably it is 10 mass% or more, More preferably, it is 20 mass% or more. If it is less than 10% by mass, performance on ice and wear resistance may be deteriorated. The BR content is preferably 70% by mass or less, more preferably 50% by mass or less. When the content of BR is within the above range, good fuel economy, wear resistance, and performance on ice can be more suitably obtained.

Styrene butadiene rubber (SBR) may be used for the rubber composition of the present invention. Thereby, better fuel economy and wear resistance can be obtained.

SBR is not particularly limited, and those generally used in the tire industry, such as emulsion-polymerized styrene butadiene rubber (E-SBR) and solution-polymerized styrene butadiene rubber (S-SBR), can be appropriately selected according to use conditions and purposes. . These may be used alone or in combination of two or more. For example, SL series manufactured by JSR Corporation, Toughden series manufactured by Asahi Kasei Chemicals Corporation, Asaprene E15 manufactured by Asahi Kasei Chemicals Corporation, Nipol series manufactured by Nippon Zeon, and the like can be used.

The styrene content of SBR is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. The styrene content is preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less, and particularly preferably 30% by mass or less. In the present invention, the styrene content of SBR is calculated by H ¹ -NMR measurement.

When the said rubber composition contains SBR, content of SBR in 100 mass% of rubber components becomes like this. Preferably it is 1 mass% or more, More preferably, it is 5 mass% or more. The SBR content is preferably 30% by mass or less, more preferably 25% by mass or less. If the SBR content exceeds 30% by mass, sufficient performance on ice may not be obtained.

The rubber component that can be used in addition to BR, NR, IR, and SBR is not particularly limited, and is styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), ethylene propylene diene rubber (EPDM), Examples include diene rubbers such as butyl rubber (IIR) and halogenated butyl rubber (X-IIR). A rubber component may be used independently and may use 2 or more types together.

In the present invention, sulfur is used to form an appropriate cross-linked chain in the polymer chain. Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur that are generally used in the rubber industry. These may be used alone or in combination of two or more.

The sulfur content is preferably 0.1 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. There exists a possibility that the effect of this invention may not fully be acquired as it is less than 0.1 mass part. The sulfur content is preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, still more preferably 4.0 parts by mass or less, particularly preferably 3.0 parts by mass or less, and most preferably 1. 5 parts by mass or less. If it exceeds 6.0 parts by mass, fuel economy, wear resistance, and performance on ice may be deteriorated. By setting the sulfur content to the above amount, the bloom of the nonionic surfactant can be suitably controlled, and the effects of the present invention can be obtained satisfactorily.

In the present invention, as the vulcanizing agent, an alkylphenol / sulfur chloride condensate (for example, tackolol V200 manufactured by Taoka Chemical Co., Ltd.) may be used in addition to sulfur.

The rubber composition of the present invention may contain silica. By blending silica, better fuel economy, wear resistance, and performance on ice can be obtained. The silica is not particularly limited, and examples thereof include dry process silica (anhydrous silicic acid), wet process silica (hydrous silicic acid) and the like. These may be used alone or in combination of two or more. Of these, wet-process silica is preferred because it has many silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of the silica is preferably 50 m ² / g or more, more preferably 100 m ² / g or more, and further preferably 150 m ² / g or more. If it is less than 50 m < ² > / g, there exists a tendency for low-fuel-consumption property, abrasion resistance, and on-ice performance to fall. The N ₂ SA is preferably 250 m ² / g or less, more preferably 210 m ² / g or less. When it exceeds 250 m ² / g, it becomes difficult to disperse, and the fuel efficiency, wear resistance, and performance on ice tend to deteriorate.
The _N 2 SA of silica is a value determined by the BET method in accordance with ASTM D3037-93.

When the rubber composition contains silica, the content of silica is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 25 parts by mass or more, particularly 100 parts by mass of the rubber component. Preferably it is 40 mass parts or more. The silica content is preferably 150 parts by mass or less, more preferably 130 parts by mass or less, still more preferably 120 parts by mass or less, and particularly preferably 100 parts by mass or less. When the content of silica exceeds 150 parts by mass, wear resistance, discoloration resistance, and tire appearance tend to deteriorate. By making the content of silica within the above range, the appearance of the tire can be further improved, and good on-ice performance and a reinforcing effect can be obtained.

The rubber composition of the present invention preferably contains a silane coupling agent together with silica.
As the silane coupling agent, any silane coupling agent conventionally used in combination with silica can be used in the rubber industry, and examples thereof include sulfide systems such as bis (3-triethoxysilylpropyl) disulfide, 3- Mercapto type such as mercaptopropyltrimethoxysilane, vinyl type such as vinyltriethoxysilane, amino type such as 3-aminopropyltriethoxysilane, glycidoxy type of γ-glycidoxypropyltriethoxysilane, 3-nitropropyltrimethoxy Examples thereof include nitro compounds such as silane and chloro compounds such as 3-chloropropyltrimethoxysilane. These may be used alone or in combination of two or more. Among these, sulfide type is preferable, and bis (3-triethoxysilylpropyl) disulfide is more preferable.

When the said rubber composition contains a silane coupling agent, Preferably content of a silane coupling agent is 2 mass parts or more with respect to 100 mass parts of silica, More preferably, it is 5 mass parts or more. If it is less than 2 parts by mass, fuel economy, wear resistance, and performance on ice tend to be reduced. The content of the silane coupling agent is preferably 20 parts by mass or less, more preferably 15 parts by mass or less. When it exceeds 20 parts by mass, there is a tendency that an effect commensurate with the increase in cost cannot be obtained.

The rubber composition of the present invention may contain carbon black. Thereby, the discoloration resistance and the appearance of the tire are improved, and good reinforcement and wear resistance are obtained.

Examples of the carbon black include GPF, FEF, HAF, ISAF, and SAF, but are not particularly limited. 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 20 m ² / g or more, and more preferably 50 m ² / g or more. If it is less than 20 m < ² > / g, there exists a possibility that sufficient reinforcement may not be acquired. The _N 2 SA is preferably 180 m ² / g or less, more preferably 120 m ² / g, more preferably ^90m 2 / g or less, ^{80 m} 2 / g or less is particularly preferred. If it exceeds 180 m ² / g, it becomes difficult to disperse, and the reinforcing property and wear resistance tend to deteriorate.
Incidentally, _N 2 SA of carbon black, JIS K 6217-2: determined by 2001.

Carbon black has a dibutyl phthalate oil absorption (DBP) of preferably 50 ml / 100 g or more, and more preferably 80 ml / 100 g or more. If it is less than 50 ml / 100 g, sufficient reinforcement may not be obtained. Further, the DBP of carbon black is preferably 200 ml / 100 g or less, more preferably 135 ml / 100 g or less, and still more preferably 115 ml / 100 g or less. When it exceeds 200 ml / 100 g, it becomes difficult to disperse, and the reinforcing property and the wear resistance tend to deteriorate.
The DBP of carbon black is measured according to JIS K 6217-4: 2001.

When the rubber composition contains carbon black, the content of carbon black is preferably 2 parts by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 2 parts by mass, sufficient reinforcement may not be obtained. The content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less. When it exceeds 50 parts by mass, fuel economy, wear resistance, and performance on ice tend to deteriorate.

In the present invention, it is preferable to add a wax in order to suppress the occurrence and progress of cracks due to ozone. In the present invention, as described above, the unevenness of the tire surface (bloom layer) formed by precipitation of wax or the like can be smoothed even if the wax is blended, and irregular reflection of light is suppressed. White discoloration can be reduced. In addition, the tire appearance is improved by giving the tire surface an appropriate black appearance and gloss. Furthermore, in this invention, since it is a specific rubber composition, favorable low fuel consumption, abrasion resistance, and performance on ice are maintained or improved.

The wax is not particularly limited, and examples thereof include petroleum waxes, natural waxes, and synthetic waxes, and those obtained by purifying or chemically treating a plurality of waxes can also be used. These waxes may be used alone or in combination of two or more.

Examples of petroleum waxes include paraffin wax and microcrystalline wax. Natural waxes are not particularly limited as long as they are derived from non-petroleum resources. For example, plant waxes such as candelilla wax, carnauba wax, wood wax, rice wax, jojoba wax; beeswax, lanolin, whale wax, etc. Animal waxes; mineral waxes such as ozokerite, ceresin, and petrolactam; and purified products thereof. Synthetic waxes include polymers such as ethylene or propylene.

When the rubber composition contains a wax, the content of the wax is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 0.5 parts by mass, sufficient ozone resistance may not be obtained. The wax content is preferably 12 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 5.0 parts by mass or less. If the amount exceeds 12 parts by mass, no further improvement in ozone resistance can be expected, and the cost may increase.

The rubber composition of the present invention may contain oil. By blending oil, processability is improved, the tire can be given flexibility, and the effects of the present invention can be obtained better. As the oil, for example, process oil, vegetable oil, or a mixture thereof can be used. As the process oil, for example, a paraffin process oil, an aroma process oil, a naphthenic process oil, or the like can be used. Specific examples of the paraffinic process oil include PW-32, PW-90, PW-150, and PS-32 manufactured by Idemitsu Kosan Co., Ltd. Specific examples of the aroma-based process oil include AC-12, AC-460, AH-16, AH-24, and AH-58 manufactured by Idemitsu Kosan Co., Ltd. As vegetable oils and fats, castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut hot water, rosin, pine oil, pineapple, tall oil, corn oil, rice bran oil, beet flower oil, sesame oil, Examples 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. Among these, paraffinic process oils and aroma based process oils are preferable, and paraffinic process oils and aroma based process oils are more preferable in combination because the effects of the present invention can be suitably obtained.

When the rubber composition contains oil, the oil content is preferably 1.0 parts by mass or more, more preferably 5.0 parts by mass or more, and still more preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. Part or more, particularly preferably 15 parts by weight or more. The oil content is preferably 60 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less. By setting the content of the oil that blooms on the tire surface itself within the above range, the bloom of the nonionic surfactant can be suitably controlled, and the effects of the present invention can be more suitably obtained. Note that when the oil content exceeds 60 parts by mass, fuel efficiency tends to deteriorate.

The rubber composition of the present invention preferably contains an anti-aging agent in order to suppress the occurrence and progression of cracks due to ozone. In the present invention, even when an anti-aging agent is added, as described above, while maintaining or improving good fuel economy, abrasion resistance, and performance on ice, browning and white discoloration can be reduced, discoloration resistance, tire Can improve the appearance.

The anti-aging agent is not particularly limited. For example, naphthylamine, quinoline, diphenylamine, p-phenylenediamine, hydroquinone derivatives, phenol (monophenol, bisphenol, trisphenol, polyphenol), thiobisphenol Series, benzimidazole series, thiourea series, phosphorous acid series, and organic thioacid series antioxidants. These may be used alone or in combination of two or more. Of these, p-phenylenediamine is preferable because ozone resistance is good and the effects of the present invention can be obtained more suitably.

As the p-phenylenediamine-based antioxidant, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N-1, 4-dimethylpentyl-N′-phenyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, N, N′-di-2-naphthyl-p-phenylenediamine, N-cyclohexyl-N′- Phenyl-p-phenylenediamine, N, N′-bis (1-methylheptyl) -p-phenylenediamine, N, N′-bis (1,4-dimethylpentyl) -p-phenylenediamine, N, N′- Bis (1-ethyl-3-methylpentyl) -p-phenylenediamine, N-4-methyl-2-pentyl-N′-phenyl-p-phenylene Amine, N, N'-diaryl -p- phenylenediamine, hindered mistakes aryl -p- phenylenediamine, phenyl hexyl -p- phenylenediamine, and the like phenyloctyl -p- phenylenediamine. These may be used alone or in combination of two or more. Among these, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylene is preferred because it has good ozone resistance, the effects of the present invention can be obtained more suitably, and the economy is excellent. Diamine is more preferred.

When the rubber composition contains an anti-aging agent, the content of the anti-aging agent 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. Preferably it is 1.0 mass part or more. If the amount is less than 0.3 parts by mass, sufficient ozone resistance may not be obtained. The content of the anti-aging agent is preferably 10 parts by mass or less, more preferably 6.0 parts by mass or less. When the amount exceeds 10 parts by mass, the bloom amount of the anti-aging agent increases, and the appearance of the tire may be deteriorated.

The rubber composition of the present invention preferably contains a vulcanization accelerator. Examples of the vulcanization accelerator include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine or aldehyde-ammonia, imidazoline, or xanthate vulcanization accelerators. Etc. These vulcanization accelerators may be used alone or in combination of two or more. Among these, a sulfenamide-based vulcanization accelerator is preferable because the effects of the present invention can be more suitably obtained, and it is more preferable to use a guanidine-based vulcanization accelerator in combination with the sulfenamide-based vulcanization accelerator. .

Examples of the sulfenamide vulcanization accelerator include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N, N -Dicyclohexyl-2-benzothiazolylsulfenamide (DCBS) and the like. These may be used alone or in combination of two or more. Among these, CBS is preferable because the effects of the present invention can be more suitably obtained, and it is more preferable to use 1,3-diphenylguanidine together with CBS.

The rubber composition of the present invention preferably contains a resin. Examples of the resin include terpene resins, rosin, rosin derivatives, coumarone resins, coumarone indene resins, styrene resins, DCPD resins, C5 petroleum resins, C9 petroleum resins, and the like. These may be used alone or in combination of two or more. Among these, terpene-based resins are preferable because good fuel economy, wear resistance, and performance on ice can be obtained.

As the terpene resin, a terpene resin, a modified terpene resin, a terpene phenol resin, or the like can be used. The softening point of the terpene resin is preferably 50 to 140 ° C, more preferably 90 to 130 ° C. The softening point of the resin is the temperature at which the sphere descends when the softening point specified in JIS K 6220-1: 2001 is measured with a ring and ball softening point measuring device.

When the said rubber composition contains resin, content of resin becomes like this. Preferably it is 0.5-50 mass parts with respect to 100 mass parts of rubber components, More preferably, it is 5-20 mass parts. When the resin content is within the above range, better fuel economy, wear resistance, and performance on ice can be obtained.

In the rubber composition of the present invention, in addition to the above-mentioned components, compounding agents generally used in the production of rubber compositions such as zinc oxide, stearic acid, tackifiers and the like can be appropriately blended.

As a method for producing the rubber composition of the present invention, a known method can be used. For example, the above components are kneaded using a rubber kneader such as an open roll or a Banbury mixer, and then vulcanized. Can be manufactured.

The rubber composition of the present invention can be suitably used for each member of a tire (particularly, a tread that constitutes the surface (outer surface) of the tire and requires good discoloration resistance and the appearance of the tire).

The pneumatic tire of the present invention can be produced by a usual method using the rubber composition. That is, by extruding a rubber composition containing the above components in accordance with the shape of a tread or the like at an unvulcanized stage, and molding it with a tire molding machine by a normal method together with other tire members, Unvulcanized tires can be formed. A tire is obtained by heating and pressurizing the unvulcanized tire in a vulcanizer.

The pneumatic tire of the present invention is used as, for example, passenger car tires, truck / bus tires, motorcycle tires, high performance tires, winter tires and the like. Especially, it is used suitably as a winter tire.

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

界面活性剤２：三洋化成工業（株）製のイオネットＰＯ６００（主成分：モノオレイン酸ポリエチレングリコール、式（１）のＲ^１：−Ｃ_１７Ｈ_３３、式（１）のｄ：１２に相当、下式で表わされる化合物）

界面活性剤３：関東化学（株）製のポリオキシエチレンドデシルエーテル
老化防止剤１：大内新興化学工業（株）製のノクラック６Ｃ（Ｎ−（１，３−ジメチルブチル）−Ｎ’−フェニル−ｐ−フェニレンジアミン）
老化防止剤２：大内新興化学工業（株）製のノクラック２２４（２，２，４−トリメチル−１，２−ジヒドロキノリン重合体）
ステアリン酸：日油（株）製のステアリン酸
硫黄：鶴見化学工業（株）製の粉末硫黄
酸化亜鉛：三井金属鉱業（株）製の亜鉛華１号
加硫促進剤１：大内新興化学社製のノクセラーＣＺ（Ｎ−シクロヘキシル−２−ベンゾチアゾリルスルフェンアミド）
加硫促進剤２：大内新興化学社製のノクセラーＤ（１，３−ジフェニルグアニジン） Hereinafter, various chemicals used in Examples and Comparative Examples will be described together.
SBR: Asaprene E15 (styrene content: 23% by mass) manufactured by Asahi Kasei Chemicals Corporation
NR: RSS # 3
BR: BR730 manufactured by JSR Corporation (cis content: 95% by mass)
Carbon Black: Show Black N330 manufactured by Cabot Japan Co., Ltd. (N ₂ SA: 75 m ² / g, DBP: 102 ml / 100 g)
Silica: Ultrasil VN3 manufactured by Evonik Degussa (N ₂ SA: 175 m ² / g)
Silane coupling agent: Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa
Wax: Ozoace wax oil manufactured by Nippon Seiwa Co., Ltd. 1: Process oil PW-32 (paraffinic process oil) manufactured by Idemitsu Kosan Co., Ltd.
Oil 2: Process X-140 (aromatic process oil) manufactured by Japan Energy Co., Ltd.
Resin: PX1150N manufactured by Yasuhara Chemical Co., Ltd. (terpene resin (pinene polymer), softening point: 115 ° C.)
Surfactant 1: Ionette DO600 manufactured by Sanyo Chemical Industries Co., Ltd. (main component: polyethylene glycol dioleate, R ² and R ³ in formula (2): -C ₁₇ H ₃₃ , e: 12 in formula (2) Equivalent compound represented by the following formula)

Surfactant 2: Ionette PO600 manufactured by Sanyo Chemical Industries, Ltd. (main component: polyethylene glycol monooleate, R ^{1 in} formula (1): —C ₁₇ H ₃₃ , equivalent to d: 12 in formula (1), Compound represented by the following formula)

Surfactant 3: Polyoxyethylene dodecyl ether aging inhibitor manufactured by Kanto Chemical Co., Ltd. 1: NOCRACK 6C (N- (1,3-dimethylbutyl) -N′-phenyl manufactured by Ouchi Shinsei Chemical Co., Ltd.) -P-phenylenediamine)
Anti-aging agent 2: Nocrack 224 (2,2,4-trimethyl-1,2-dihydroquinoline polymer) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Stearic acid: sulfur stearate manufactured by NOF Corporation: powdered sulfur oxide manufactured by Tsurumi Chemical Industry Co., Ltd .: zinc oxide No. 1 vulcanization accelerator 1: Mitsui Metal Mining Co., Ltd. 1: Ouchi Shinsei Chemical Co., Ltd. Noxeller CZ (N-cyclohexyl-2-benzothiazolylsulfenamide)
Vulcanization accelerator 2: Noxeller D (1,3-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Co., Ltd.

In accordance with the formulation shown in Tables 1 to 4, chemicals other than sulfur and a vulcanization accelerator were kneaded using a 1.7 L Banbury mixer until the temperature reached 160 ° C. Next, using an open roll, sulfur and a vulcanization accelerator were added to the obtained kneaded product and kneaded until reaching 105 ° C., thereby obtaining an unvulcanized rubber composition. Next, the obtained unvulcanized rubber composition was press vulcanized at 160 ° C. for 15 minutes to obtain a vulcanized rubber composition.

The obtained vulcanized rubber composition was evaluated by the following, and the results are shown in Tables 1 to 4. In addition, the reference comparative example of Table 1 was set to Comparative Example 1. Similarly, the standard comparative examples in Tables 2, 3, and 4 were referred to as Comparative Examples 4, 6, and 8, respectively.

<Low fuel consumption>
Using a spectrometer manufactured by Ueshima Seisakusho, tan δ of the vulcanized rubber composition was measured at a dynamic strain amplitude of 1%, a frequency of 10 Hz, and a temperature of 50 ° C. The reciprocal value of tan δ was expressed as an index with the reference comparative example being 100. The larger the index, the lower the rolling resistance and the better the fuel efficiency. The target index was 98 or higher.

<Abrasion resistance>
Using a LAT tester (Laboratory Abbreviation and Skid Tester), the volume loss of each vulcanized rubber composition was measured under the conditions of a load of 50 N, a speed of 20 km / h, and a slip angle of 5 °. The results are shown as an index with the volume loss amount of the reference comparative example as 100. It shows that it is excellent in abrasion resistance, so that an index | exponent is large.

<Preparation of ozone-degraded sample>
In accordance with JIS K 6259 “Vulcanized Rubber and Thermoplastic Rubber-Determination of Ozone Resistance”, a test piece of a predetermined size was prepared from the obtained vulcanized rubber composition, and a dynamic ozone deterioration test was performed. An ozone-degraded sample was obtained. The test was performed for 48 hours under conditions of a reciprocating frequency of 0.5 ± 0.025 Hz, an ozone concentration of 50 ± 5 pphm, a test temperature of 40 ° C., and a tensile strain of 20 ± 2%.

<Discoloration resistance evaluation>
The a and b values of the ozone-deteriorated sample were obtained using a Minolta Color Difference Meter (CR-310) (L * a * b * color system). The index was set to (a2 + b2) −0.5 and the index of the reference comparative example was set to 100 (index of each formulation / index of the reference comparative example × 100). A larger index indicates less discoloration and better resistance to discoloration.

<Appearance evaluation>
An ozone-degraded sample was taken outdoors and the appearance was evaluated using the following indicators.
◎ Blacker and more glossy than the reference comparison example ○ Blacker than the reference comparison example and slightly shiny △ Brown equivalent to the reference comparison example × Browner than the reference comparison example

(Dynamic viscoelasticity test)
Using a viscoelasticity measurement tester manufactured by TS Instruments, Inc., for each vulcanized rubber composition, the elastic modulus at a temperature of 0 ° C., a frequency of 5 Hz, and an amplitude of 0.1% (0.1% G ^* ) And a value (ΔG ^* ) obtained by subtracting 0.1% G ^* from the elastic modulus (40% G ^* ) at an amplitude of 40%. An index s represented by the following formula s = (ΔG ^* ) / (0.1% G ^* ) is used as a balance index between performance on ice and steering stability (s is a value of 0 <s <1). Relative values with Comparative Examples 1, 4, 6, and 8 as 100 were used as indices. The larger the index, the better the balance between on-ice performance and steering stability, indicating better on-ice performance.

Inclusive of 0.1 to 6.0 parts by mass of the nonionic surfactant represented by the above formula (1) and / or the above formula (2) with respect to 100 parts by mass of the rubber component, The total content of butadiene rubber, natural rubber, and isoprene rubber is 70% by mass or more, and in examples containing sulfur, discoloration resistance while maintaining or improving good fuel economy, wear resistance, and performance on ice. The appearance of rubber (tire) was improved.

Claims (7)

Inclusive of 0.1 to 6.0 parts by mass of the nonionic surfactant represented by the following formula (1) and / or the following formula (2) with respect to 100 parts by mass of the rubber component, A tire rubber composition having a total content of butadiene rubber, natural rubber, and isoprene rubber of 70% by mass or more and containing sulfur.

(In the formula (1), ^{R 1} is, .d representing a hydrocarbon group of 6 to 26 carbon atoms represents an arbitrary integer.)

(In formula (2), R ² and R ³ are the same or different and represent a hydrocarbon group having 6 to 26 carbon atoms. E represents an arbitrary integer.) The tire rubber composition according to claim 1, comprising 15 to 150 parts by mass of silica with respect to 100 parts by mass of the rubber component. The rubber composition for a tire according to claim 1 or 2, wherein the content of the styrene-butadiene rubber is 1 to 30% by mass in 100% by mass of the rubber component. The rubber composition for tire according to any one of claims 1 to 3, comprising 0.1 to 6.0 parts by mass of the sulfur with respect to 100 parts by mass of the rubber component. The pneumatic tire which has a tire member produced using the rubber composition in any one of Claims 1-4. The pneumatic tire according to claim 5, wherein the tire member is a tread. The pneumatic tire according to claim 5 or 6, which is a winter tire.