JP2014214162A - Rubber composition for tire and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a tire improved in low fuel consumption performance, wear resistance and wet grip performance in a good balance, and to provide a method for producing the same and a tire using the rubber composition for a tread.SOLUTION: There is provided a rubber composition for a tire obtained by kneading: a master batch A containing an epoxidized natural rubber and silica; a master batch B containing a modified styrene-butadiene rubber, having a functional group capable of reacting with a silanol group at at least one of polymerization terminals, and silica; and a silane coupling agent with a kneading extruder.

Description

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

In recent years, silica has been widely used as a reinforcing filler for tire treads in order to reduce fuel consumption and improve wet grip performance in passenger cars. However, silica is generally less dispersible than carbon black and wear resistance. It is difficult to exert desired performance. Therefore, development of modified polymers such as styrene butadiene rubber modified with a functional group having reactivity with silica has been promoted, and performance such as fuel efficiency, wear resistance, wet grip performance and the like has been improved.

Even if components such as modified polymer, silica, and silane coupling agent are kneaded by a conventional method using a Banbury mixer, the reaction between the silane coupling agent and silica and the reaction between the modified polymer and silica compete. For reasons such as reaction, it is difficult to sufficiently advance these reactions, and there is a problem that desired performance cannot be imparted to the compounded rubber.

Therefore, a masterbatch is prepared by kneading epoxidized natural rubber and silica in advance and further kneaded with other components, a masterbatch containing a modified styrene butadiene rubber and silica prepared in advance, epoxy Improvements by production methods such as a method for producing a rubber composition in which components such as a masterbatch containing a modified natural rubber and silica and a silane coupling agent are kneaded with a Banbury mixer have been attempted.

However, recently, the required level of performance has been increased, and further improvements in performance such as low fuel consumption, wear resistance, and wet grip performance have been demanded.

JP 2010-150481 A JP 2010-202819 A

The present invention solves the above problems and provides a rubber composition for tires with improved fuel economy, wear resistance and wet grip performance in a well-balanced manner, a method for producing the same, and a tire using the rubber composition in a tread. The purpose is to do.

The present invention includes a master batch A containing epoxidized natural rubber and silica, a master batch B containing a modified styrene butadiene rubber having a functional group capable of reacting with a silanol group at at least one polymerization terminal and silica, and a silane cup The present invention relates to a rubber composition for tires obtained by kneading a ring agent with a kneading extruder.

In the rubber composition, the master batches A and B preferably do not contain a silane coupling agent.
Further, the master batch A contains 20 to 80 parts by mass of the silica with respect to 100 parts by mass of the epoxidized natural rubber, and the master batch B contains the silica with respect to 100 parts by mass of the modified styrene butadiene rubber. It is preferable to contain 20-80 mass parts.
Furthermore, the epoxidation rate of the epoxidized natural rubber is preferably 5 to 25 mol%.

The present invention includes the step (I) of preparing the master batches A and B and the step (II) of kneading the prepared master batches A and B and the silane coupling agent with a kneading extruder. The present invention relates to a method for producing a rubber composition for tires.
In the said manufacturing method, it is preferable that the said process (II) is performed at 140-170 degreeC.

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

According to the present invention, a master batch A containing epoxidized natural rubber and silica, a master batch B containing a modified styrene butadiene rubber having a functional group capable of reacting with a silanol group at at least one polymerization terminal and silica, Since it is a rubber composition for tires obtained by kneading a silane coupling agent with a kneading extruder, by applying the rubber composition to a tread or the like, low fuel consumption, wear resistance and wet grip performance are balanced. An improved pneumatic tire can be provided.

The tire rubber composition of the present invention includes a masterbatch A containing an epoxidized natural rubber and silica, a modified styrene butadiene rubber having a functional group capable of reacting with a silanol group at at least one polymerization terminal, and a master containing silica. It is obtained by kneading batch B and a silane coupling agent with a kneading extruder.

Master batches A and B prepared by advance reaction of a modified polymer such as epoxidized natural rubber or modified styrene butadiene rubber with silica and other components such as a silane coupling agent may be simply kneaded with a Banbury mixer. Since the kneading temperature is not stabilized, the reaction between the silane coupling agent and silica does not proceed sufficiently, and it is difficult to obtain a desired effect. On the other hand, since the present invention can control the master batches A and B and the silane coupling agent to a predetermined kneading temperature when kneading and extruding with a kneading extruder, the chemical reaction can proceed sufficiently. It becomes possible. Accordingly, the reaction between the epoxidized natural rubber and the modified styrene butadiene rubber and silica proceeds sufficiently during the production of the master batches A and B, and the reaction between the silane coupling agent and silica proceeds sufficiently during the kneading extrusion process, thereby dispersing the silica. As a result, the fuel efficiency, wear resistance, and wet grip performance can be remarkably and well-balanced.

The rubber composition for tires of the present invention includes, for example, a step (I) of preparing the master batches A and B, and a step of kneading the prepared master batches A and B and the silane coupling agent with a kneading extruder. It can be prepared by a production method including (II).

<Process (I): Preparation process of master batches A and B>
As the epoxidized natural rubber (ENR) used for the preparation of the master batch A, a commercially available epoxidized natural rubber may be used, or natural rubber may be epoxidized. Examples of the method for epoxidizing natural rubber include a chlorohydrin method, a direct oxidation method, a hydrogen peroxide method, an alkyl hydroperoxide method, and a peracid method. Examples of the peracid method include a method of reacting natural rubber with an organic peracid such as peracetic acid or performic acid.

The epoxidation rate of ENR (the ratio of epoxy groups to the isoprene unit of natural rubber) is preferably 5 mol% or more, and more preferably 10 mol% or more. If the amount is less than 5 mol%, the amount of bonding with silica is small, and thus there is a tendency that low fuel consumption (rolling resistance) cannot be sufficiently improved. The epoxidation rate is preferably 25 mol% or less, and more preferably 20 mol% or less. If it exceeds 25 mol%, the glass transition temperature is high, and the wear resistance and rolling resistance tend to deteriorate.
The epoxidation rate can be measured by NMR.

As a modified styrene butadiene rubber (modified SBR) having a functional group capable of reacting with a silanol group at at least one polymerization terminal used in the preparation of masterbatch B, it can react with a silanol group at one or both ends of the polymer chain. SBR modified by introducing a functional group.

When styrene butadiene rubber (SBR) is used as a rubber introduced with a functional group capable of reacting with a silanol group at the polymer end, it has a high coefficient of friction on the wet road surface, excellent wear resistance, wet grip performance, and wear resistance. It can be improved. Examples of SBR include solution-polymerized styrene butadiene rubber (S-SBR) and emulsion-polymerized styrene butadiene rubber (E-SBR). S-SBR can be produced by living polymerization and functional groups can be easily introduced into the terminal. Is preferred.

Examples of the functional group introduced into the modified SBR include an amino group, a hydroxyl group, an epoxy group, an alkylsilyl group, an alkoxysilyl group, a carboxyl group, and a lactam group, but it has excellent reactivity with silica and has low fuel consumption. From the viewpoint of sufficiently improving, an alkylsilyl group, an alkoxysilyl group, an epoxy group, and an amino group are preferable, and an amino group is preferable. The functional group introduced into the modified SBR may be one type or two or more types.

The styrene content of the modified SBR is preferably 23.5% by mass or more, and more preferably 30% by mass or more. If it is less than 23.5% by mass, grip performance under dry conditions tends to be low, and wear resistance tends to be low. The styrene content is preferably 50% by mass or less, and more preferably 40% by mass or less. If it exceeds 50% by mass, fuel efficiency tends to deteriorate.
In the present specification, the amount of styrene is calculated by H ¹ -NMR measurement.

The amount of vinyl bonds in the modified SBR is preferably 15% by mass or more, and more preferably 20% by mass or more. If it is less than 15% by mass, the balance between wet grip performance and low fuel consumption tends to deteriorate. The vinyl bond content is preferably 60% by mass or less, and more preferably 40% by mass or less. When it exceeds 60% by mass, the wear resistance is remarkably deteriorated and the vulcanization time tends to increase.
In the present specification, the vinyl bond amount (1,2-bond butadiene unit amount) can be measured by infrared absorption spectrum analysis.

It does not specifically limit as silica used for masterbatch A and B, For example, what is prepared by a wet method or a dry process is mentioned.

The BET specific surface area (BET) of silica is preferably 80 m ² / g or more, and more preferably 100 m ² / g or more. When it is less than 80 m ² / g, the wear resistance tends to decrease. Further, the BET of silica is preferably 220 m ² / g or less, and more preferably 200 m ² / g or less. If it exceeds 220 m ² / g, the processability of rubber kneading tends to be reduced.
Here, the BET specific surface area is a value measured by the BET method according to ASTM D3037-81.

In the preparation of master batch A (ENR master batch), the blending amount of silica is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and the upper limit is preferably 80 parts by mass or less with respect to 100 parts by mass of ENR. 60 parts by mass or less is more preferable. If the amount is less than 20 parts by mass, the fuel economy tends not to be improved sufficiently. If the amount exceeds 80 parts by mass, the processability of the rubber kneading process tends to be lowered.

The master batch A can be produced by kneading ENR and silica using, for example, a roll, a Banbury mixer, a kneader, a closed kneader, or the like. At the time of producing the masterbatch, it is desirable that the reaction between the epoxy group of ENR and the silanol group of silica is allowed to react to the utmost limit.

As for the temperature (kneading temperature etc.) at the time of preparing the ENR master batch, the lower limit is preferably 130 ° C. or higher, more preferably 140 ° C. or higher, and the upper limit is preferably 170 ° C. or lower, more preferably 160 ° C. or lower. The lower limit of the preparation time (kneading time, etc.) is preferably 1 minute or longer, more preferably 3 minutes or longer, and the upper limit is preferably 10 minutes or shorter, more preferably 6 minutes or shorter. If the preparation temperature or preparation time is less than the lower limit, the reaction of ENR and silanol groups may not proceed sufficiently, and if the upper limit is exceeded, the processability of rubber kneading tends to be reduced.

In the preparation of master batch B (modified SBR master batch), the blending amount of silica is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, and the upper limit is 80 parts by mass or less with respect to 100 parts by mass of the modified SBR. Is preferable, and 60 mass parts or less is more preferable. If it is less than 20 parts by mass, the fuel efficiency tends not to be sufficiently improved, and if it exceeds 80 parts by mass, the processability of rubber kneading tends to be reduced.

The master batch B can be produced by kneading the modified SBR and silica using, for example, a roll, a Banbury mixer, a kneader, a closed kneader, or the like. At the time of preparing the master batch, the reaction between the functional group introduced into the modified SBR and the silanol group is sufficiently advanced.

As for the temperature (kneading temperature etc.) at the time of modified SBR preparation, the lower limit is preferably 130 ° C. or higher, more preferably 140 ° C. or higher, and the upper limit is preferably 170 ° C. or lower, more preferably 160 ° C. or lower. The lower limit of the preparation time (kneading time, etc.) is preferably 1 minute or longer, more preferably 3 minutes or longer, and the upper limit is preferably 10 minutes or shorter, more preferably 6 minutes or shorter. If the preparation temperature or preparation time is less than the lower limit, the reaction between the functional group introduced into the modified SBR and the silanol group may not proceed sufficiently, and if the upper limit is exceeded, the processability of rubber kneading tends to decrease. is there.

In the preparation of the master batch A or B, other components may be added as long as the effects of the present invention are not impaired. However, when a silane coupling agent is blended, the blending amount of each master batch A, 5 mass parts or less are preferable with respect to 100 mass parts of silica in B, 3 mass parts or less are more preferable, and it is most preferable not to add. If a silane coupling agent is added during the preparation of master batches A and B, the reaction between the modified SBR or ENR and silica competes with the reaction between the silane coupling agent and silica, and both reactions do not proceed sufficiently. There is a possibility that silica is unevenly distributed.

<Process (II): Kneading extrusion process using a kneading extruder>
In the step (II), the master batches A and B and the silane coupling agent prepared in the step (I) are kneaded by a kneading extruder. Thereby, since kneading | mixing temperature can be stabilized, reaction of a silica and a silane coupling agent fully advances, and desired performance is obtained.

As the kneading extruder, for example, a continuous kneading extruder such as a single direction extruder, a different direction rotating twin screw extruder, a different direction or same direction rotating multi-screw extruder such as a same direction rotating twin screw extruder, or the like is preferably used. Can be used.

The lower limit of the kneading temperature in step (II) is preferably 140 ° C or higher, more preferably 150 ° C or higher, and the upper limit is preferably 170 ° C or lower, more preferably 165 ° C or lower. The lower limit of the kneading time is preferably 1 minute or longer, more preferably 3 minutes or longer, and the upper limit is preferably 10 minutes or shorter, more preferably 6 minutes or shorter. If the temperature or time is less than the lower limit, the reaction between the silica and the silane coupling agent may not proceed sufficiently, and if the upper limit is exceeded, the processability of rubber kneading may be reduced and desired performance may not be obtained.

In the step (II), the blending amount of the ENR master batch is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, and the upper limit is preferably 200 parts by mass or less with respect to 100 parts by mass of the modified SBR master batch. 150 parts by mass or less is more preferable. When the amount is less than 30 parts by mass, the wear resistance tends to decrease, and when the amount exceeds 200 parts by mass, the wet grip performance tends to decrease.

It does not specifically limit as a silane coupling agent mix | blended by process (II), The thing currently used in the rubber industry field | area is applicable. Specifically, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, bis (3-trimethoxysilylpropyl) Tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (4-trimethoxysilylbutyl) tetrasulfide, bis (3-methyldiethoxysilylpropyl) tetrasulfide, bis (2-methyldimethoxysilylethyl) tetra Sulfide, bis (4-methyldimethoxysilylbutyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-triethoxysilylbutyl) trisulfide Bis (3-trimethoxysilylpropyl) trisulfide, bis (2-trimethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, Bis (triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) ) Disulfide, bis (4-trimethoxysilylbutyl) disulfide, bis (3-methyldiethoxysilylpropyl) disulfide, bis (2-methyldiethoxysilylpropyl) disulfide, bis (4-methyldiethoxysilylpro) Disulfide, bis (3-methyldimethoxysilylpropyl) disulfide, bis (2-methyldimethoxysilylpropyl) disulfide, bis (4-methyldimethoxysilylptyl) disulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltri Ethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptotriethyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltomethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3 -(2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxy Sisilane, γ-glycidoxypropylmethyldimethoxysilane and the like can be mentioned, and these silane coupling agents may be used alone or in combination of two or more. Especially, since the coupling agent addition effect and cost can be compatible, bis (triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3 -Trimethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-methyldiethoxysilylpropyl) disulfide, bis (3-methyldimethoxysilylpropyl) disulfide and the like are preferably used.

The compounding amount of the silane coupling agent is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and an upper limit of 12 parts by mass or less with respect to 100 parts by mass of silica contained in the rubber composition of the present invention. Is preferable, and 8 parts by mass or less is more preferable. If it is less than 1 part by mass, there is a tendency that a sufficient coupling effect cannot be obtained, and if it exceeds 12 parts by mass, the coupling effect is not improved, which may be disadvantageous in terms of cost.

In the step (II), in addition to the master batches A and B and the silane coupling agent, other components may be blended within a range that does not inhibit the effect.

Further, the rubber of the present invention can be obtained by kneading the kneaded product obtained in step (II) and other compounding materials using a roll, a Banbury mixer, a kneader, a closed kneader, etc., and further vulcanizing. A composition is obtained.

As other compounding materials, other rubber components such as natural rubber and / or diene-based synthetic rubber other than the ENR and modified SBR may be added. Examples of the diene synthetic rubber include styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and butyl rubber. (IIR) and the like. These may be used alone or in combination of two or more. When other rubber components are contained, the content of the other rubber components is preferably 20% by mass or less, more preferably 10% by mass or less, in 100% by mass of the rubber component in the rubber composition of the present invention. More preferably, it is 5 mass% or less.

The rubber composition of the present invention preferably contains carbon black. Thereby, the intensity | strength of rubber | gum can be improved. As carbon black, HAF, ISAF, SAF, GPF, FEF, etc. can be used, for example.

When carbon black is contained, the nitrogen adsorption specific surface area (N ₂ SA) of the carbon black is preferably 90 m ² / g or more, and more preferably 105 m ² / g or more. Further, the _N 2 SA is preferably 150 meters ² / g or less, more preferably 120 m ² / g. When it is less than 90 m ² / g, the wear resistance tends to decrease, and when it exceeds 150 m ² / g, rubber kneadability and dispersibility tend to decrease.
The nitrogen adsorption specific surface area of carbon black can be measured according to JIS K 6217-2: 2001.

The content of carbon black is preferably 5 parts by mass or more, more preferably 8 parts by mass or more with respect to 100 parts by mass of the rubber component in the rubber composition. If it is less than 5 mass parts, there exists a tendency for reinforcement property to fall. Moreover, this content becomes like this. Preferably it is 30 mass parts or less, More preferably, it is 20 mass parts or less. When it exceeds 30 mass parts, there exists a tendency for rolling resistance to deteriorate.

In addition to the above components, the rubber composition of the present invention contains additives usually used in the rubber industry, such as vulcanizing agents, vulcanization accelerators, zinc oxide, stearic acid, various anti-aging agents, and waxes. It can mix | blend suitably.

Although the said rubber composition can be applied to each member of a tire, it can be used conveniently as a tread especially.

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 each member such as a tread at an unvulcanized stage, and molded by a normal method on a tire molding machine. Thus, after forming an unvulcanized tire, the tire can be manufactured by heating and pressing in a vulcanizer.

The pneumatic tire of the present invention can be suitably applied to passenger cars, trucks and buses, and low-pollution vehicles (eco-cars) compatible with global environmental conservation.

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

Various chemicals used in Production Examples, Examples and Comparative Examples will be described.
Modified S-SBR1: HPR355 (3-aminopropyltrimethoxysilane-modified, styrene content: 27% by mass) manufactured by JSR Corporation
Modified S-SBR2: ASAPRENE Y031 manufactured by Asahi Kasei Corporation (styrene content: 26% by mass)
ENR-10: Epoxidized natural rubber (epoxidation rate: 10 mol%) manufactured by Kumpulan Guthrie Berhad
ENR-25: Epoxidized natural rubber (epoxidation rate: 25 mol%) manufactured by Kumpulan Guthrie Berhad
Carbon Black: Show Black N220 (N ₂ SA: 115 m ² / g) manufactured by Cabot Japan
Silica: Ultrazil VN3 manufactured by Degussa (N ₂ SA: 175 m ² / g)
Silane coupling agent: Si-69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa
Oil: JOMO process X140 manufactured by Japan Energy Co., Ltd.
Wax: Sannoc Wax anti-aging agent manufactured by Ouchi Shinsei Chemical Industry Co., Ltd .: NOCRACK 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-product manufactured by Ouchi New Chemical Co., Ltd.) Phenylenediamine)
Stearic acid: Zinc stearate manufactured by NOF Corporation: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powder sulfur vulcanization accelerator manufactured by Karuizawa Sulfur Co., Ltd. TBBS: Ouchi Shinsei Chemical Industry ( Noxeller NS (N-tert-butyl-2-benzothiazylsulfenamide)
Vulcanization accelerator DPG: Noxeller D (N, N'-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Co., Ltd.

(Production Example 1 ENR Masterbatch (1))
Using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd., 50 parts by mass of silica was mixed with 100 parts by mass of ENR-10 at 140 ° C. for 4 minutes to prepare an ENR masterbatch (1). .

(Production Example 2 ENR Masterbatch (2))
An ENR master batch (2) was prepared in the same manner as in Production Example 1 except that 70 parts by mass of silica was mixed with 100 parts by mass of ENR-25.

(Production Example 3 Preparation of Modified SBR Masterbatch (1))
A modified SBR master batch (1) was prepared in the same manner as in Production Example 1 except that 50 parts by mass of silica was mixed with 100 parts by mass of the modified S-SBR1 (HPR355).

(Production Example 4 Preparation of Modified SBR Masterbatch (2))
A modified SBR master batch (2) was produced in the same manner as in Production Example 1, except that 70 parts by mass of silica was mixed with 100 parts by mass of the modified S-SBR2 (Y031).

〔Example〕
According to the formulation shown in Table 1, the ENR master batch, the modified S-SBR master batch, and the silane coupling agent were kneaded and extruded under the following conditions using a Banbury mixer to obtain a kneaded product 1 (step II).
Kneading temperature: 160 ° C
Kneading time: 2 minutes

Next, using a 1.7 L Banbury mixer (manufactured by Kobe Steel, Ltd.), the obtained kneaded product 1 and the components shown in Table 1 were kneaded for 5 minutes at 150 ° C. to obtain a kneaded product 2. (Base kneading step) Further, using an open roll, sulfur and a vulcanization accelerator are added to the obtained kneaded product 2 and kneaded for 5 minutes at 90 ° C. to obtain an unvulcanized rubber composition. (Final kneading process). The obtained unvulcanized rubber composition was press vulcanized at 150 ° C. for 30 minutes to produce a vulcanized rubber composition.
Further, the obtained unvulcanized rubber composition is processed into a tread shape, pasted with another tire member, molded into a tire, and vulcanized at 170 ° C. for 15 minutes to obtain a test tire (tire size: 195 / 65R15).

[Comparative Example]
In accordance with the contents shown in Table 2, a component other than sulfur and a vulcanization accelerator was kneaded for 5 minutes at 150 ° C. using a 1.7 L Banbury mixer (manufactured by Kobe Steel). Except that an unrolled rubber composition was obtained by adding sulfur and a vulcanization accelerator to the obtained kneaded product using an open roll and kneading for 5 minutes at 90 ° C. A vulcanized rubber composition and a test tire were produced in the same manner as in the examples.

The following evaluation was performed using the obtained vulcanized rubber composition and test tire. The results are shown in Tables 1 and 2.

(Rolling resistance index)
Using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.), tan δ of each formulation was measured under conditions of a temperature of 70 ° C., an initial strain of 10%, and a dynamic strain of 2%. The index was expressed by the following formula. The larger the index, the better the rolling resistance characteristics.
(Rolling resistance index) = (tan δ of Comparative Example 2) / (tan δ of each formulation) × 100

(Abrasion test)
The amount of lamborn wear was measured with a lamborn wear tester under conditions of a temperature of 20 ° C., a slip rate of 20%, and a test time of 5 minutes. The volume loss amount of each formulation was expressed as an index according to the following calculation formula, with the loss amount of Comparative Example 2 being 100. The higher the index, the better the wear resistance.
(Abrasion index) = (loss amount of Comparative Example 2) / (loss amount of each formulation) × 100

(WET index)
A test tire was mounted on a traction test vehicle, and a μMax value was measured on a lubricated asphalt road surface under conditions of a speed of 64 km, an internal pressure of 200 kPa, and a load of 4.8 kN. Based on the tire of Comparative Example 2, the evaluation was made based on the index determined by the following formula. The larger the index, the better the wet grip performance.
(ΜMax value of each example) / (μMax value of Comparative Example 2) × 100

Compared to Comparative Example 1 in which ENR masterbatch, modified SBR masterbatch, silica, silane coupling agent and the like were kneaded with a Banbury mixer, the ENR masterbatch, modified In Example 1 in which the SBR masterbatch and silica were kneaded and extruded with a kneading extruder and then components such as a silane coupling agent were kneaded with a Banbury mixer, the rolling resistance performance, wear resistance, and wet grip performance were further improved. A remarkable improvement effect was exhibited.

Moreover, the remarkable improvement effect was acquired also when it produced through the kneading | mixing extrusion process using ENR-25, modified | denatured S-SBR1 or 2, (Examples 2-3 and Comparative Examples 3-4).

Claims (7)

Master batch A containing epoxidized natural rubber and silica, master batch B containing modified styrene butadiene rubber and silica having a functional group capable of reacting with a silanol group at at least one polymerization terminal, and a silane coupling agent A tire rubber composition obtained by kneading with a kneading extruder. The tire rubber composition according to claim 1, wherein the master batches A and B do not contain a silane coupling agent. The master batch A contains 20 to 80 parts by mass of the silica with respect to 100 parts by mass of the epoxidized natural rubber,
The tire rubber composition according to claim 1 or 2, wherein the master batch B contains 20 to 80 parts by mass of the silica with respect to 100 parts by mass of the modified styrene butadiene rubber. The tire rubber composition according to any one of claims 1 to 3, wherein the epoxidized natural rubber has an epoxidation rate of 5 to 25 mol%. The step (I) of preparing the master batches A and B, and the step (II) of kneading the prepared master batches A and B and the silane coupling agent with a kneading extruder. The manufacturing method of the rubber composition for tires in any one. The method for producing a rubber composition for a tire according to claim 5, wherein the step (II) is performed at 140 to 170 ° C. The tire which has a tread produced using the rubber composition for tires in any one of Claims 1-4.