JP2009263574A - Copolymer and rubber composition using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition having excellent balance of processability, high mileage properties, and wet grip properties. <P>SOLUTION: A copolymer is prepared by copolymerizing styrene and/or 1,3-butadiene, with an alkoxysilylstyrene represented by general formula of the figure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a styrene-butadiene-alkoxysilylstyrene copolymer and a rubber composition using the same.

  In recent years, social demands for reducing carbon dioxide emissions have been increasing from the standpoints of resource and energy conservation and environmental protection. Various countermeasures such as reducing the weight of automobiles and using electric energy have been studied for the purpose of reducing carbon dioxide emissions from automobiles. As a common problem for automobiles, it is necessary to improve fuel efficiency by improving rolling resistance of tires. Further, there is an increasing demand for automobiles to improve safety during driving. The fuel efficiency and safety of these automobiles depend largely on the performance of the tire used, and there is an increasing demand for improvement in fuel efficiency, steering stability, and durability for automobile tires. These tire characteristics depend on various factors such as the tire structure and materials used, but the performance of the rubber composition used for the tread portion in contact with the road surface is particularly suitable for tire characteristics such as fuel efficiency, safety and durability. The contribution of is large. For this reason, many technical improvements of rubber compositions for tires have been studied and proposed and put into practical use.

  For example, the tire tread rubber is required to have low hysteresis loss for improving fuel efficiency and high wet skid resistance for improving wet grip performance. However, the relationship between low hysteresis loss and wet skid resistance is contradictory, and it is difficult to solve the problem with only one performance improvement. A typical method for improving the rubber composition for tires is improvement of raw materials used, improvement of the structure of raw rubber represented by SBR and BR, reinforcing filler such as carbon black and silica, vulcanizing agent, Improvements in the structure and composition of plasticizers and the like have been made.

Silica is often used as a filler in order to improve the balance between fuel efficiency and wet grip performance. However, when silica is used, kneading is difficult, and good dispersibility and workability of silica are problematic. It has become. As an improvement method, Patent Document 1 describes a method of blending a polyalkylene glycol with a rubber composition to obtain a rubber composition having excellent processability. However, in this technology, polyalkylene glycol having a molecular weight of 1000 or more is a solid at room temperature, so that the Mooney viscosity of the rubber composition is increased, and when the molecular weight is low or the compounding amount is large, the rubber surface bleeds out. There is a problem that poor adhesion occurs.
Japanese Patent Laid-Open No. 9-3245

  Provided is a rubber composition having an excellent balance of processability, low fuel consumption and wet grip performance.

The present invention relates to a copolymer obtained by copolymerizing styrene and / or 1,3-butadiene and alkoxysilylstyrene represented by the following general formula.
(General formula)

(In the formula, R ¹ , R ² and R ³ are each independently a hydrocarbon group having 1 to 4 carbon atoms, which may be the same or different.)
The copolymer of the present invention is characterized in that the content of alkoxysilylstyrene in the copolymer is 0.05 to 35% by mass.

  The present invention also relates to a rubber composition comprising a diene rubber and the copolymer.

  The rubber composition of the present invention contains 5 to 150 parts by mass of silica with respect to 100 parts by mass of the rubber component.

  Compared to conventional rubber compositions, it is possible to obtain a rubber composition having an excellent balance of processability, fuel efficiency and wet grip performance.

<Copolymer>
The copolymer in the present invention is a copolymer obtained by copolymerizing styrene and / or 1,3-butadiene and alkoxysilylstyrene represented by the following general formula.
(General formula)

(R in the formula is a hydrocarbon group having 1 to 4 carbon atoms, which may be the same or different.)
The molecular weight of the copolymer is preferably 300 to 2,000,000.

(Alkoxysilylstyrene)
R ¹ , R ² and R ^{3 in} the general formula of the alkoxysilylstyrene are each independently a hydrocarbon group having 1 to 4 carbon atoms, which may be the same or different. When the carbon number of R exceeds 4, not only the synthesis of the alkoxysilylstyrene becomes difficult, but the performance improvement effect of the rubber composition containing a copolymer obtained using the same tends to be small. The alkoxysilyl styrene may be used alone or in combination of two or more.

  The content of alkoxysilylstyrene in the copolymer is preferably 0.05 to 35% by mass, particularly preferably 0.1 to 20% by mass. When the content of the nitrogen-containing compound is less than 0.05% by mass, it is difficult to obtain the effect of improving fuel economy and wet grip performance, while when it exceeds 30% by mass, the cost tends to be high.

<Method for producing copolymer>
(Polymerization method)
The polymerization method of the copolymer is not particularly limited, and any of a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method can be used, but a solution polymerization method is particularly preferable from the viewpoint of the stability of the alkoxysilyl group. . Moreover, any of a batch type and a continuous type may be sufficient as the superposition | polymerization form.

  When the solution polymerization method is used, the monomer concentration (total of styrene, 1,3-butadiene and alkoxysilylstyrene) in the solvent is preferably 5% by mass or more, and more preferably 10% by mass or more. When the monomer concentration in the solution is less than 5% by mass, the amount of the copolymer obtained is small and the cost tends to increase. The monomer concentration in the solvent is preferably 50% by mass or less, and more preferably 30% by mass or less. When the monomer concentration in the solvent exceeds 50% by mass, the solution viscosity becomes too high, stirring becomes difficult, and polymerization tends to be difficult.

(Polymerization initiator in anionic polymerization)
When anionic polymerization is performed, the polymerization initiator is not particularly limited, but an organic lithium compound is preferably used. As the organic lithium compound, those having an alkyl group having 2 to 20 carbon atoms are preferable. For example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, tert- Octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, cyclopentyl lithium, reaction products of diisopropenylbenzene and butyl lithium, etc. Among these, n-butyllithium or sec-butyllithium is preferable from the viewpoints of availability, safety, and the like.

(Method of anionic polymerization)
There is no restriction | limiting in particular as a method of manufacturing a copolymer by anionic polymerization using the said organolithium compound as a polymerization initiator, A conventionally well-known method can be used.

Specifically, in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, for example, butyl lithium is used as a polymerization initiator, and a randomizer is used as necessary. The target copolymer can be obtained by anionic polymerization of styrene and / or 1,3-butadiene and alkoxysilylstyrene in the presence of (hydrocarbon solvent in anionic polymerization)
The hydrocarbon solvent is preferably one having 3 to 8 carbon atoms, such as propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene and trans-2. -Butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like. These may be used alone or in combination of two or more.

(Randomizer in anionic polymerization)
The randomizer is a microstructure control of a conjugated diene moiety in a copolymer, for example, an increase in 1,2-bond in butadiene, an increase in 3,4-bond in isoprene, or a composition of monomer units in the copolymer. It is a compound having an action of controlling distribution, for example, randomizing butadiene units and styrene units in a butadiene-styrene copolymer. The randomizer is not particularly limited, and any known compound generally used as a conventional randomizer can be used. For example, dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, bistetrahydrofurylpropane, triethylamine, pyridine, N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, 1,2-di Examples include ethers such as piperidinoethane and tertiary amines. Further, potassium salts such as potassium-t-amylate and potassium-t-butoxide, and sodium salts such as sodium-t-amylate can also be used. These randomizers may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of randomizer used is preferably 0.01 molar equivalents or more, more preferably 0.05 molar equivalents or more per mole of the organic lithium compound. If the amount of randomizer used is less than 0.01 molar equivalent, the effect of addition tends to be small and it tends to be difficult to randomize. The amount of randomizer used is preferably 1000 molar equivalents or less, more preferably 500 molar equivalents or less, per mole of the organic lithium compound. If the amount of randomizer used exceeds 1000 molar equivalents, the reaction rate of the monomer changes greatly, and conversely, it tends to be difficult to randomize.

  In this invention, after this reaction, alcohol etc. can be added as needed for the purpose of stopping a known anti-aging agent or polymerization reaction.

<Rubber composition>
(Rubber component)
In the present invention, a diene rubber is preferably used as the rubber component of the rubber composition. The diene rubber is composed of natural rubber and / or diene synthetic rubber. Examples of the diene synthetic rubber include isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), and acrylonitrile butadiene rubber (NBR). ), Chloroprene rubber (CR), butyl rubber (IIR) and the like. Among these, NR, BR, and SBR are preferable because grip performance and wear resistance are well-balanced. These rubbers may be used alone or in combination of two or more.

(Copolymer)
In the rubber composition of the present invention, the blending amount of the copolymer is preferably 3 parts by mass or more, particularly 5 parts by mass or more, out of 100 parts by mass of the rubber component. If the blending amount is less than 3 parts by mass, it tends to be difficult to obtain an effect of improving fuel economy and wet grip performance.

(silica)
The rubber composition of the present invention is characterized by blending silica as a reinforcing agent. Preferably nitrogen adsorption specific surface area of the silica (N ₂ SA) is 50 to 300 m ² / g, and particularly preferably from 80~250m ² / g. Silica with a nitrogen adsorption specific surface area of less than 50 m ² / g has a small reinforcing effect and tends to have low wear resistance, and silica exceeding 300 m ² / g has poor dispersibility, increases hysteresis loss, and decreases fuel efficiency. Tend to.

  Moreover, 5-150 mass parts is preferable with respect to 100 mass parts of rubber components, and, as for the compounding quantity of the said silica, 10-100 mass parts is more preferable. If the amount of silica is less than 5 parts by mass, the wear resistance tends to be insufficient, while if the amount of silica exceeds 150 parts by mass, the workability tends to deteriorate. Silica may be used alone or in combination of two or more.

(Silane coupling agent)
When silica is blended, a silane coupling agent may be used in combination. Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2-triethoxy). Silylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyl Trimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarba Moyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilyl Propyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide And dimethoxymethylsilylpropylbenzothiazole tetrasulfide. Of these, bis (3-triethoxysilylpropyl) tetrasulfide and 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide are preferable from the viewpoint of improving reinforcing properties. These silane coupling agents may be used alone or in combination of two or more.

  The compounding amount of the silane coupling agent is preferably 1 part by mass or more and more preferably 2 parts by mass or more with respect to 100 parts by mass of the silica. If the compounding amount of the silane coupling agent is less than 1 part by mass, the viscosity of the unvulcanized rubber composition tends to be high and the processability tends to be poor. Moreover, it is preferable that it is 20 mass parts or less with respect to 100 mass parts of said silica, and, as for the compounding quantity of a silane coupling agent, it is more preferable that it is 15 mass parts or less. If the blending amount of the silane coupling agent exceeds 20 parts by mass, the blending effect of the silane coupling agent as much as the blending amount cannot be obtained, and the cost tends to increase.

(Anti-aging agent)
The tire rubber composition of the present invention may contain an anti-aging agent. As the anti-aging agent, amine-based, phenol-based, and imidazole-based compounds, carbamic acid metal salts, waxes, and the like can be appropriately selected and used.

(Softener)
The tire rubber composition of the present invention may contain a softening agent. Softeners include petroleum-based softeners such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt and petroleum jelly, and fatty oil-based softeners such as soybean oil, palm oil, castor oil, linseed oil, rapeseed oil and coconut oil. Agents, waxes such as tall oil, sub, beeswax, carnauba wax and lanolin, and fatty acids such as linoleic acid, palmitic acid, stearic acid and lauric acid. The blending amount of the softening agent is preferably 100 parts by mass or less with respect to 100 parts by mass of the rubber component, and in this case, there is a risk of reducing the wet grip performance when the rubber composition is used in a tire. Less is.

(Vulcanizing agent)
The tire rubber composition of the present invention may contain a vulcanizing agent. As the vulcanizing agent, an organic peroxide or a sulfur vulcanizing agent can be used. Examples of the organic peroxide include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5-dimethyl-2, 5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne- 3 or 1,3-bis (t-butylperoxypropyl) benzene or the like can be used. Moreover, as a sulfur type vulcanizing agent, sulfur, morpholine disulfide, etc. can be used, for example. Of these, sulfur is preferred.

(Vulcanization accelerator)
The tire rubber composition of the present invention may contain a vulcanization accelerator. Vulcanization accelerators include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, or xanthate vulcanization accelerators. Those containing at least one of them can be used.

(Vulcanization aid)
The tire rubber composition of the present invention may contain a vulcanization aid. As the vulcanization aid, stearic acid, zinc oxide (zinc white) or the like can be used.

  In the tire rubber composition of the present invention, various reinforcing agents, various oils, plasticizers, coupling agents, etc., various compounding agents and additives blended for tires or general rubber compositions are blended. Can do. Moreover, the content of these compounding agents and additives can also be set to general amounts. The rubber composition of the present invention thus obtained exhibits an excellent balance in processability, fuel efficiency and wet grip performance.

<Method for producing rubber composition>
The rubber composition of the present invention can be produced by a conventionally known production method, and the production method is not limited. For example, it can be produced by kneading each of the above components using a kneading machine such as a Banbury mixer or a kneading roll under ordinary methods and conditions.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these.

<Measurement and identification method>
(Measurement of number average molecular weight Mn)
The number average molecular weight Mn was calibrated with standard polystyrene using a differential refractometer as a detector using a GPC-8000 series apparatus manufactured by Tosoh Corporation.

(Structural identification of alkoxysilylstyrene and copolymers)
The structure identification of the alkoxysilylstyrene and the copolymer was measured using an apparatus of JNM-ECA series manufactured by JEOL Ltd.

<Synthesis of alkoxysilylstyrene>
(Alkoxysilylstyrene (1))
150 ml of n-pentane and 180 mmol of dimethyldichlorosilane were added to a three-necked flask sufficiently purged with nitrogen, and a toluene solution of isopropyl alcohol (180 mmol) / triethylamine (180 mmol) was added dropwise at 0 ° C. over 1 hour. Furthermore, after stirring at room temperature for 2 hours, isopropoxydimethylsilyl chloride was obtained by distillation purification.

  Next, 690 mmol of magnesium and 120 mL of THF were added to a three-necked flask sufficiently purged with nitrogen, and 510 mmol of 4-bromostyrene was added dropwise at 0 ° C. over 1 hour to obtain (4-vinylphenyl) magnesium bromide.

Then, 50 mL of dehydrated THF and 70 mmol of isopropoxydimethylsilyl chloride were added to a three-necked flask sufficiently substituted with nitrogen, and 100 mL of a previously prepared (4-vinylphenyl) magnesium bromide 70 mmol / THF solution was added dropwise over 1 hour. After stirring at room temperature overnight, the residue was purified by distillation to obtain alkoxysilylstyrene (1) (isopropoxydimethylsilylstyrene (C ₁₃ H ₂₀ OSi)). Table 1 shows the results of ¹ H-NMR measurement of the alkoxysilylstyrene (1).

(Alkoxysilylstyrene (2))
180 mL of THF and 460 mmol of dimethyldichlorosilane were added to a three-necked flask sufficiently purged with nitrogen, and (4-vinylphenyl) magnesium bromide 510 mmol was added dropwise at 0 ° C. over 1 hour. It was added dropwise over time. After stirring overnight at room temperature, the residue was purified by distillation to obtain alkoxysilylstyrene (2) (tert-butoxydimethylsilylstyrene (C ₁₄ H ₂₂ OSi)). Table 2 shows the ¹ H-NMR measurement results of the alkoxysilylstyrene (2).

<Synthesis of copolymer>
(Copolymer (1))
Cyclohexane 20 mL, styrene 18 mmol, alkoxysilylstyrene (1) 3 mmol, and sec-BuLi 0.11 mmol were added to a pressure-resistant container sufficiently purged with nitrogen, followed by stirring at −30 ° C. for 19 hours. Thereafter, alcohol was added to stop the reaction, and copolymer (1) was obtained by reprecipitation purification. <Mn = 36000, alkoxysilylstyrene content = 26% by mass, styrene content = 74% by mass>
(Copolymer (2))
20 mL of cyclohexane, 21 mmol of styrene and 0.107 mmol of sec-BuLi were added to a pressure vessel sufficiently substituted with nitrogen, and the mixture was stirred at 0 ° C. for 15 hours. Thereafter, 4.6 mmol of alkoxysilylstyrene (1) was added and stirred at 0 ° C. for 17 hours. Thereafter, alcohol was added to stop the reaction, and a copolymer (2) was obtained by reprecipitation purification. <Mn = 62000, alkoxysilylstyrene content = 32% by mass, styrene content = 68% by mass>
(Copolymer (3))
20 mL of cyclohexane, 18 mmol of styrene, 83 mmol of 1,3-butadiene, 1.1 mmol of alkoxysilylstyrene (1) and 0.2 mmol of sec-BuLi were added to a pressure-resistant container sufficiently purged with nitrogen, and stirred at 0 ° C. for 19 hours. Thereafter, alcohol was added to stop the reaction, and a copolymer (3) was obtained by reprecipitation purification. <Mn = 39000, alkoxysilylstyrene content = 4% by mass, styrene content = 28% by mass, 1,3-butadiene content = 68% by mass>
(Copolymer (4))
20 mL of cyclohexane, 23 mmol of styrene, 87 mmol of 1,3-butadiene, and 0.2 mmol of sec-BuLi were added to a pressure vessel sufficiently substituted with nitrogen, and the mixture was stirred at 0 ° C. for 20 hours. Thereafter, 0.84 mmol of alkoxysilylstyrene (1) was added and stirred at 0 ° C. for 16 hours. Thereafter, alcohol was added to stop the reaction, and a copolymer (4) was obtained by reprecipitation purification. <Mn = 14,000, alkoxysilyl styrene content = 3 mass%, styrene content = 33 mass%, 1,3-butadiene content = 64 mass%>
(Copolymer (5))
Cyclohexane 20 mL, styrene 15 mmol, alkoxysilylstyrene (1) 2 mmol, and sec-BuLi 1.2 mmol were added to a pressure-resistant container sufficiently purged with nitrogen, and stirred at −10 ° C. for 30 minutes. Thereafter, alcohol was added to stop the reaction, and a copolymer (5) was obtained by reprecipitation purification. <Mn = 1100, alkoxysilylstyrene content = 21% by mass, styrene content = 79% by mass>
(Copolymer (6))
20 mL of cyclohexane, 14 mmol of styrene, 1.7 mmol of alkoxysilylstyrene (2) and 1.5 mmol of sec-BuLi were added to a pressure-resistant container sufficiently purged with nitrogen, and stirred at −10 ° C. for 30 minutes. Thereafter, alcohol was added to stop the reaction, and a copolymer (6) was obtained by reprecipitation purification. <Mn = 1200, alkoxysilylstyrene content = 21% by mass, styrene content = 79% by mass>
Below, the various chemical | medical agents used at the time of the synthesis | combination of alkoxysilyl styrene (1)-(2) and copolymer (1)-(6) are demonstrated.

n-pentane: manufactured by Kanto Chemical Co., Inc. Dimethyldichlorosilane: KA-22 manufactured by Shin-Etsu Silicone Co., Ltd.
Isopropyl alcohol: manufactured by Kanto Chemical Co., Ltd. Triethylamine: manufactured by Kanto Chemical Co., Ltd. Magnesium: manufactured by Kanto Chemical Co., Ltd. THF: Tetrahydrofuran manufactured by Kanto Chemical Co., Ltd. 4-bromostyrene: manufactured by Kanto Chemical Co., Ltd. tert -Butoxy potassium: manufactured by Kanto Chemical Co., Inc. Cyclohexane: manufactured by Kanto Chemical Co., Ltd. Styrene: manufactured by Kanto Chemical Co., Ltd. sec-BuLi: 1.0 Msec-BuLi cyclohexane manufactured by Kanto Chemical Co., Ltd., n-hexane solution 1, 3-Butadiene: manufactured by Tokyo Chemical Industry Co., Ltd. <Examples 1-7 and Comparative Examples 1-2>
According to the formulation shown in Table 1, kneading and compounding were carried out to obtain various test rubber compositions. These blends were press vulcanized at 170 ° C. for 15 minutes to obtain vulcanizates, which were evaluated for processability, fuel economy and wet grip performance by the test methods described below.

<Evaluation items and test methods>
(Processability)
The rubber sheet skin after kneading was subjected to sensory evaluation by visual observation. The comparative example 1 is set to 3, and a five-step evaluation is performed. The larger the number, the better the rubber sheet skin and the better the workability.

(Low fuel consumption)
Using a spectrometer manufactured by Ueshima Seisakusho, tan δ 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 Comparative Example 1 being 100. The larger the value, the lower the rolling resistance and the lower the fuel consumption.

(Wet grip performance)
Grip performance was evaluated using a flat belt friction tester (FR5010 type) manufactured by Ueshima Seisakusho. Using a cylindrical rubber test piece with a width of 20 mm and a diameter of 100 mm, the slip ratio of the sample with respect to the road surface is changed from 0 to 70% under the conditions of a speed of 20 km / hour, a load of 4 kgf, and a road surface temperature of 20 ° C. The maximum value of the coefficient of friction to be used was read. Comparative example 1 was taken as 100 and displayed as an index. The larger the index, the higher the wet grip performance.

Below, various chemical | medical agents used by the Example and the comparative example are demonstrated.
NR: RSS # 3
SBR: SL574 manufactured by JSR Corporation
Silica: Ultrasil VN3 manufactured by Tegussa
Silane coupling agent: Si69 manufactured by Tegussa
Polyethylene glycol 200: manufactured by Wako Pure Chemical Industries, Ltd. Polyethylene glycol 2000: manufactured by Wako Pure Chemical Industries, Ltd. Anti-aging agent: NOCRACK 6C (N-1,3-dimethylbutyl- manufactured by Ouchi Shinsei Chemical Co., Ltd.) N'-phenyl-p-phenylenediamine)
Stearic acid: Stearic acid manufactured by Nippon Oil & Fats Co., Ltd. Zinc oxide: Zinc Hana No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Noxeller CZ made by
Vulcanization accelerator 2: Noxeller D from Ouchi Shinsei Chemical Co., Ltd.
<Evaluation results>
As shown in Table 1, the rubber compositions of Examples 1 to 7 containing a copolymer of styrene and / or 1,3-butadiene and alkoxysilyl styrene were compared with the rubber compositions of Comparative Examples 1 and 2. It has been clarified that the rubber composition has an excellent balance of processability, low fuel consumption and wet grip performance.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Claims (4)

A copolymer obtained by copolymerizing styrene and / or 1,3-butadiene and alkoxysilylstyrene represented by the following general formula.
(General formula)

(In the formula, R ¹ , R ² and R ³ are each independently a hydrocarbon group having 1 to 4 carbon atoms, which may be the same or different.)   The copolymer according to claim 1, wherein the content of alkoxysilylstyrene in the copolymer is 0.05 to 35% by mass.   A rubber composition comprising a diene rubber and the copolymer according to claim 1.   The rubber composition according to claim 3, wherein 5 to 150 parts by mass of silica is contained with respect to 100 parts by mass of the rubber component.