JP5044381B2 - Rubber composition for inner liner and tire having inner liner using the same - Google Patents

Description

  The present invention relates to a rubber composition for an inner liner and a tire having an inner liner using the same.

  In recent years, due to the strong social demand for low fuel consumption of vehicles, tires have been reduced in heat and weight, and among the tire members, they are arranged inside the tire and the air from inside the pneumatic tire to the outside The inner liner having a function of improving the air retention by reducing the amount of leakage (air permeation amount) has been reduced in weight.

  Currently, as a rubber composition for an inner liner, the air retention of a tire is improved by blending a butyl rubber and a diene rubber, and blending the butyl rubber in a high amount. However, butyl rubber is excellent in reducing the air permeation amount, but the hysteresis loss of the resulting rubber composition is large. The higher the butyl rubber content, the greater the heat generated by the tire and the fuel efficiency characteristics of the car. There was a problem that decreased.

  As a technique for solving these problems, a technique containing plate-like mica (see Patent Document 1) is known, but it does not sufficiently improve the air retention of the tire and reduce the rolling resistance, Furthermore, there was a problem that the inner liner was cracked.

JP-A-11-140234

  An object of this invention is to provide the rubber composition for inner liners which can improve air permeation resistance, exothermic property, and workability.

  The present invention relates to a rubber component 100 comprising 20 to 60% by weight of a butyl rubber and 30 to 80% by weight of at least one diene rubber selected from the group consisting of natural rubber, isoprene rubber, epoxidized natural rubber and butadiene rubber. 10 to 50 parts by weight of mica having an average particle diameter of 25 to 100 μm and an aspect ratio of 25 to 100, 2 to 30 parts by weight of carbon black, and 5 to 45 parts by weight of silica with respect to parts by weight, The present invention relates to a rubber composition for an inner liner, wherein the total content of carbon black and silica is 20 to 47 parts by weight, and further the total content of mica, carbon black and silica is 30 to 80 parts by weight.

  The present invention also relates to a tire having an inner liner using the rubber composition for an inner liner.

  According to the present invention, a rubber composition for an inner liner that can improve air permeation resistance, heat build-up, and processability by containing a predetermined amount of a predetermined rubber component, predetermined mica, carbon black, and silica. Can be provided.

  The rubber composition for an inner liner of the present invention contains a predetermined rubber component, mica, carbon black and silica.

  The rubber component contains at least one diene rubber selected from the group consisting of butyl rubber and natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber (ENR), and butadiene rubber (BR). .

  Examples of the butyl rubber include butyl rubber (IIR), brominated butyl rubber (Br-IIR), and chlorinated butyl rubber (Cl-IIR). Of these, brominated butyl rubber or chlorinated butyl rubber is preferred from the viewpoint that the vulcanization rate is moderately high and the hardness (Hs) can be increased.

  The content of the butyl rubber in the rubber component is 20% by weight or more, preferably 25% by weight or more from the viewpoint of excellent air permeation resistance and crack growth resistance. The content of the butyl rubber is 60% by weight or less, preferably 55% by weight or less from the viewpoint that tan δ can be lowered and heat generation of the inner liner can be suppressed.

  There is no restriction | limiting in particular as NR, RSS # 3, TSR20 etc. which are generally used in the tire industry are mention | raise | lifted. Among these, RSS # 3 is preferable from the viewpoint that there is little mixing of foreign matters and excellent breaking strength. Moreover, IR is also generally used in the tire industry.

  The content of NR and / or IR in the rubber component is 30% by weight or more, preferably 35% by weight or more from the viewpoint of excellent roll processability and breaking strength. Further, the content of NR and / or IR is 80% by weight or less, preferably 75% by weight or less from the viewpoint that excellent air permeation resistance can be obtained.

  As ENR, commercially available ENR may be used, or NR may be epoxidized. The method for epoxidizing NR is not particularly limited, and a chlorohydrin method, a direct oxidation method, a hydrogen peroxide method, an alkyl hydroperoxide method, a peracid method and the like are used. Examples of the peracid method include a method of reacting an organic peracid such as peracetic acid or performic acid with natural rubber.

  The epoxidation rate of ENR is preferably 15 mol% or more, and more preferably 20 mol% or more from the viewpoint of excellent air permeation resistance. Further, the epoxidation rate of ENR is preferably 55 mol% or less, more preferably 50 mol% or less, from the viewpoint of excellent low heat build-up.

  As such an epoxidized natural rubber, specifically, “ENR25” manufactured by Kumplan Guthrie Berhad, which has an epoxidation rate of 25%, and Kumplan Langley, a epoxidation rate of 50%. "ENR50" manufactured by Guthrie Berhad).

  The content of ENR in the rubber component is 30% by weight or more, preferably 35% by weight or more from the viewpoint of excellent breaking strength. The content of ENR in the rubber component is 80% by weight or less, preferably 70% by weight or less from the viewpoint that a large amount of butyl rubber having excellent air permeation resistance is blended.

  Examples of BR include BR150B and BR130B manufactured by Ube Industries, Ltd., which are 1,4-high cis polybutadiene rubbers commonly used in the tire industry and the like. In addition, butadiene rubber containing 1,2-syndiotactic polybutadiene crystals (SPB-containing BR) or tin-modified butadiene rubber (modified BR) may be used.

  When the SPB-containing BR is used, it is preferable that a highly crystalline 1,2-syndiotactic polybutadiene crystal is dispersed in a high cis-content BR such as VCR412 manufactured by Ube Industries, Ltd.

  When the SPB-containing BR is used, the viscosity increases when the rubber compound is not vulcanized, and the productivity at the time of kneading is excellent.

  The content of 1,2-syndiotactic polybutadiene crystals (SPB) in the SPB-containing BR is preferably 3% by weight or more, and more preferably 5% by weight or more. If the content of SPB is less than 3% by weight, the ratio of SPB is small, so the viscosity is low, and there is a tendency that a sufficient improvement effect on productivity at the time of kneading cannot be obtained. The SPB content is preferably 25% by weight or less, more preferably 20% by weight or less. If the SPB content exceeds 25% by weight, the dispersibility of the polybutadiene crystals tends to decrease, and the crack growth resistance tends to decrease.

  When using a modified BR, it is obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound, and the ends of the modified BR molecules are bonded with tin-carbon bonds. It is preferable.

  Examples of the lithium initiator include lithium compounds such as alkyl lithium, aryl lithium, allyl lithium, vinyl lithium, organic tin lithium, and organic nitrogen lithium compounds. By using a lithium compound as an initiator for the modified BR, a modified BR having a high vinyl bond amount and a low cis bond amount can be produced.

  Tin compounds include tin tetrachloride, butyltin trichloride, dibutyltin dichloride, dioctyltin dichloride, tributyltin chloride, triphenyltin chloride, diphenyldibutyltin, triphenyltin ethoxide, diphenyldimethyltin, ditolyltin chloride, diphenyltin dioctano Ate, divinyldiethyltin, tetrabenzyltin, dibutyltin distearate, tetraallyltin, p-tributyltin styrene, etc., are not particularly limited and may be used alone or in combination of two or more. .

  In the modified BR, the content of tin atoms is preferably 50 ppm or more, and more preferably 60 ppm or more. When the tin atom content is less than 50 ppm, the effect of promoting the dispersion of carbon black in the modified BR is small, and tan δ tends to deteriorate. The tin atom content is preferably 3000 ppm or less, more preferably 2500 ppm or less, and even more preferably 250 ppm or less. When the content of tin atoms exceeds 3000 ppm, the kneaded product is not well-organized and the edges are not aligned, so the extrudability of the kneaded product tends to deteriorate.

  The molecular weight distribution (Mw / Mn) of the modified BR is preferably 2 or less, and more preferably 1.5 or less. When Mw / Mn of the modified BR exceeds 2, the dispersibility of carbon black and tan δ tend to deteriorate. The preferred lower limit of Mw / Mn is 1.

  The vinyl bond amount of the modified BR is preferably 5% by weight or more, and more preferably 7% by weight or more. When the vinyl bond content of the modified BR is less than 5% by weight, it tends to be difficult to polymerize (manufacture) the modified BR. Further, the vinyl bond amount of the modified BR is preferably 50% by weight or less, and more preferably 20% by weight or less. If the vinyl bond content of the modified BR exceeds 50% by weight, the crack growth resistance tends to deteriorate.

  The content of BR in the rubber component is 30% by weight or more, preferably 35% by weight or more from the viewpoint of excellent crack growth resistance. The BR content in the rubber component is 80% by weight or less, preferably 75% by weight or less, from the viewpoint of excellent air permeation resistance.

  Other rubber components include styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), etc., but may not be included because of high tan δ and low breaking strength. preferable.

  Examples of mica (mica) include mascobite (muscovite), phlogopite (phlogopite), biotite (biotite), and the like. These may be used alone or in combination of two or more. Of these, phlogopite is preferred because it has a higher aspect ratio than other mica and has an excellent air blocking effect.

  The average particle diameter of mica is 25 μm or more, preferably 30 μm or more, from the viewpoint that an excellent effect of improving air permeation resistance can be obtained. The average particle diameter of mica is 100 μm or less, preferably 70 μm or less from the viewpoint of suppressing the occurrence of cracks starting from mica and the cracking of mica due to bending fatigue. Here, the average particle diameter of mica means the average value of the long diameter of mica.

  The aspect ratio of mica is 25 or more, preferably 30 or more from the viewpoint that excellent air permeation resistance can be obtained. Further, the aspect ratio of mica is 100 or less, preferably 70 or less, from the viewpoint of maintaining the strength of mica, suppressing cracking of mica, and being excellent in dispersibility in rubber. Here, the aspect ratio means the ratio of the maximum major axis to the thickness (maximum major axis / thickness) in mica.

  The mica used in the present invention can be obtained by a grinding method such as wet grinding or dry grinding. Wet pulverization produces a clean surface and has a slightly high effect of improving air permeation resistance. Further, dry pulverization has respective characteristics that the manufacturing process is simple and the cost is low. It is preferable to use properly depending on each case.

  The content of mica is 10 parts by weight or more, preferably 20 parts by weight or more with respect to 100 parts by weight of the rubber component, from the viewpoint that sufficient air permeation resistance, heat generation and crack growth resistance can be obtained as an inner liner. It is. The mica content is not more than 50 parts by weight, preferably not more than 45 parts by weight, more preferably not more than 40 parts by weight, from the viewpoint that sufficient tear strength is obtained and the generation of cracks is suppressed.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 20 m ² / g or more, more preferably 25 m ² / g or more, from the viewpoint that sufficient reinforcement can be obtained. Further, N ₂ SA of carbon black is preferably 100 m ² / g or less, and more preferably 90 m ² / g or less, from the viewpoint of setting an appropriate rubber hardness and suppressing heat generation.

  The content of the carbon black is 2 parts by weight or more, preferably 10 parts by weight or more with respect to 100 parts by weight of the rubber component, from the viewpoint of suppressing deterioration due to ultraviolet rays and being excellent in oil resistance at the time of processing or using naphtha oil. It is. The carbon black content is 30 parts by weight or less, preferably 25 parts by weight or less, based on 100 parts by weight of the rubber component, from the viewpoint of excellent low heat build-up.

  Silica includes those prepared by a wet method and those prepared by a dry method, but is not particularly limited.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 20 m ² / g or more, more preferably 30 m ² / g or more, from the viewpoint that sufficient reinforcement can be obtained. The N ₂ SA of the silica, from the viewpoint of suppressing exothermic, is preferably from 200 meters ² / g, more preferably at most 190 m ² / g.

  The content of silica is 5 parts by weight or more, preferably 7 parts by weight or more with respect to 100 parts by weight of the rubber component, from the viewpoint of excellent breaking strength and reinforcing property of the rubber fabric during processing. Further, the content of silica is 45 parts by weight or less, preferably 30 parts by weight or less with respect to 100 parts by weight of the rubber component, from the viewpoint of excellent low heat build-up.

  When the content of silica is 5 to 10 parts by weight, there is no problem in dispersibility, and therefore it is not necessary to add a silane coupling agent. When the silica content exceeds 10 parts by weight, it is preferable to add a silane coupling agent in order to suppress reaggregation of silica.

  The silane coupling agent is not particularly limited, and those conventionally used in combination with silica can be used. For example, 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-triethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-triethoxysilylbutyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (2-trimet Xylylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) Disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetra Sulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N Dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, etc. Sulfides, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, etc. mercapto, vinyltriethoxysilane, vinyltrimethoxysilane, etc. Vinyl-based, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyl Amino-based compounds such as pyrtriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyl Glycidoxy type such as diethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, nitro type such as 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyl Examples include chloro-based compounds such as triethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane.

  The content of the silane coupling agent is preferably 6 parts by weight or more, and 8 parts by weight or more with respect to 100 parts by weight of silica, from the viewpoint of improving the dispersibility of silica and being excellent in suppressing reaggregation. Is more preferable. Further, the content of the silane coupling agent is preferably 10 parts by weight or less and more preferably 9 parts by weight or less with respect to 100 parts by weight of silica from the viewpoint of excellent breaking strength.

  The total content of carbon black and silica is 20 parts by weight or more, preferably 22 parts by weight or more with respect to 100 parts by weight of the rubber component, from the viewpoint of excellent breaking strength and workability. The total content of carbon black and silica is 47 parts by weight or less, preferably 45 parts by weight or less, from the viewpoint of excellent low heat build-up.

  The total content of mica, carbon black and silica is 30 parts by weight or more, preferably 35 parts by weight or more with respect to 100 parts by weight of the rubber component, from the viewpoint of excellent breaking strength, processability and air permeation resistance. Further, the total content of mica, carbon black and silica is 80 parts by weight or less, preferably 75 parts by weight or less from the viewpoint of excellent low heat build-up.

  The rubber composition for an inner liner of the present invention preferably further contains sulfur.

  The sulfur content is preferably 0.2 parts by weight or more, more preferably 0.45 parts by weight or more with respect to 100 parts by weight of the rubber component, from the viewpoint that a sufficient vulcanization rate can be obtained. In addition, the sulfur content is preferably 1.2 parts by weight or less, more preferably 1.0 part by weight or less from the viewpoint of suppressing thermal curing during running and being excellent in crack growth resistance. When insoluble sulfur is contained as sulfur, the sulfur content refers to the content of pure sulfur content excluding oil.

  The rubber composition for an inner liner of the present invention preferably further contains a vulcanization accelerator.

  As vulcanization accelerators, tetrabenzylthiuram disulfide, tetrakis (2-ethylhexyl) thiuram disulfide, tetramethylthiuram disulfide, zinc dike can be used because the vulcanization rate can be kept as fast as possible to meet the actual vulcanization productivity. It is preferable to include a thiuram super vulcanization accelerator such as benzyldithiocarbamate.

  The content of the super vulcanization accelerator in the vulcanization accelerator is preferably 10% by weight or more, more preferably 15% by weight or more from the viewpoint that a sufficient vulcanization acceleration effect can be obtained. Further, the content of the super vulcanization accelerator is preferably 80% by weight or less, more preferably 70% by weight or less from the viewpoint that a sufficient crosslinking density is obtained and an appropriate breaking strength and hardness (Hs) are obtained. .

  The content of the vulcanization accelerator is preferably 0.8 parts by weight or more, more preferably 1.0 parts by weight or more with respect to 100 parts by weight of the rubber component, from the viewpoint that sufficient breaking strength and Hs can be obtained. Further, the content of the vulcanization accelerator is preferably 3.0 parts by weight or less, and preferably 2.0 parts by weight or less from the viewpoint that an appropriate crosslinking density and Hs are obtained and sufficient crack growth resistance is obtained. More preferred.

  The rubber composition for an inner liner of the present invention can be blended with mineral oil from the viewpoint of excellent compatibility with butyl rubber, excellent processability to rubber rolls and sheets and adhesiveness. Specific examples of the mineral oil include Diana Process PA32 manufactured by Idemitsu Kosan Co., Ltd., mineral oil manufactured by Japan Energy Co., Ltd., and Super Oil M32 manufactured by Shin Nippon Oil Co., Ltd.

  In addition to the rubber component, mica, carbon black, silica, sulfur, vulcanization accelerator and mineral oil, the rubber composition for an inner liner of the present invention is a compounding agent generally used in the tire industry, such as an oxidation Zinc, an antioxidant, stearic acid, a compatibilizing agent, and the like can be appropriately blended.

  The tire of the present invention is produced by an ordinary method using the rubber composition for an inner liner of the present invention as an inner liner. That is, the rubber composition for an inner liner of the present invention is extruded in accordance with the shape of the inner liner at an unvulcanized stage, and bonded together with other tire members on a tire molding machine to form an unvulcanized tire. . The tire of the present invention can be produced by heating and pressurizing this unvulcanized tire in a vulcanizer.

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

Various chemicals used in Examples and Comparative Examples will be described together.
Butyl rubber: Exon chlorobutyl 1068 (chlorobutyl rubber) manufactured by ExxonMobil
Natural rubber (NR): RSS # 3
Epoxidized natural rubber (ENR): ENR25 (Epoxidation rate: 25 mol%) manufactured by Kunpu Langurs
Tin-modified butadiene rubber (modified BR): BR1250H manufactured by Nippon Zeon Co., Ltd. (polymerized using lithium as an initiator, vinyl bond content: 10 to 13% by weight, Mw / Mn: 1.5, tin atom content : 250ppm)
Polybutadiene rubber containing 1,2-syndiotactic polybutadiene crystals (SPB-containing BR): VCR617 (1,2-syndiotactic polybutadiene crystal dispersion, 1,2-syndiotactic polybutadiene crystals manufactured by Ube Industries, Ltd.) Content: 17% by weight)
Carbon black: Seast V manufactured by Tokai Carbon Co., Ltd. (N660, N ₂ SA: 27 m ² / g)
Silica: Z115GR manufactured by Rhodia (N ₂ SA: 112 m ² / g)
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa
Mica 1: Mica (Mica) S-200HG manufactured by Rebco Co., Ltd. (Frogobite, average particle size: 50 μm, aspect ratio: 55)
Mica 2: Mica (Mica) S-325 manufactured by Rebco Co., Ltd. (Frogobite, average particle size: 27 μm, aspect ratio: 30)
Mica 3: Mica (Mica) S-XF manufactured by Rebco Co., Ltd. (Frogbite, average particle size: 3 μm, aspect ratio: 15)
Zinc oxide: Silver candy R made by Toho Zinc Co., Ltd.
Anti-aging agent: NOCRACK 224 (2,2,4-trimethyl-1,2-dihydroquinoline polymer) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Stearic acid: Soil-insoluble sulfur manufactured by Nippon Oil & Fats Co., Ltd .: Seimisulfur manufactured by Nippon Kibushi Kogyo Co., Ltd. (60% insoluble matter due to carbon disulfide, 10% oil content)
Vulcanization accelerator DM: Noxeller DM (di-2-benzothiazolyl disulfide) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Vulcanization accelerator TBZTD: TBZTD (tetrabenzylthiuram disulfide) manufactured by Flexis
Mineral oil: Diana Process PA32 manufactured by Idemitsu Kosan Co., Ltd.

Examples 1-13 and Comparative Examples 1-13
In accordance with the formulation shown in Table 1, using a Banbury mixer, chemicals other than sulfur and a vulcanization accelerator were added and kneaded for 4 minutes at 150 ° C. to obtain a kneaded product. Thereafter, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 4 minutes at 80 ° C. using a biaxial open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was rolled into a sheet with a mold and press-vulcanized for 12 minutes under the condition of 170 ° C., so that the vulcanized rubbers of Examples 1 to 13 and Comparative Examples 1 to 13 were obtained. A sheet was produced. In Examples 1 to 13 and Comparative Examples 1 to 13, the content of the vulcanization accelerator was adjusted to have the same degree of hardness (Hs).

(Roll processability)
In the process of producing the vulcanized rubber sheet, when the kneaded material obtained from the Banbury mixer is applied to a heated roll (temperature: 80 ° C.) to a thickness of about 8 mm, the roll is wound with appropriate adhesion to the roll. It was visually evaluated as follows that there was no sticking, no float or rubber falling.
◎: Excellent ○: Good △: Allowable lower limit ×: Unacceptable XX: Not workable at all

(Viscoelasticity test)
Using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho, the loss tangent tan δ of the vulcanized rubber sheet at 70 ° C. was measured under conditions of a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain of 2%. The smaller the tan δ, the smaller the heat generation and the better the low heat build-up, and the tan δ of 0.16 or less means the low heat build-up, Tan δ is about 0.16.

(Air permeability test)
The air permeation amount of the vulcanized rubber sheet was measured according to ASTM D-1434-75M method. The air permeation resistance index of Comparative Example 1 was set to 100, and the air permeation amount of each formulation was displayed as an index by the following calculation formula. The larger the air permeation resistance index, the smaller the air permeation amount of the vulcanized rubber sheet, and the better the air permeation resistance of the vulcanized rubber sheet.
(Air permeability resistance index) = (Air permeation amount of Comparative Example 1)
÷ (air permeation amount of each formulation) x 100

  The above evaluation results are shown in Tables 1 and 2.

Claims (2)

20-60% by weight of butyl rubber,
And 100 parts by weight of a rubber component containing 30 to 80% by weight of at least one diene rubber selected from the group consisting of natural rubber, isoprene rubber, epoxidized natural rubber and tin-modified butadiene rubber,
10 to 50 parts by weight of mica having an average particle diameter of 25 to 100 μm and an aspect ratio of 25 to 100,
Containing 2 to 30 parts by weight of carbon black, and 5 to 45 parts by weight of silica,
The total content of carbon black and silica is 20 to 47 parts by weight;
Furthermore, the rubber composition for the inner liner, wherein the total content of the mica, carbon black and silica is 30 to 80 parts by weight,
A rubber composition for an inner liner which essentially contains an epoxidized natural rubber and a tin-modified butadiene rubber in the diene rubber . A tire having an inner liner using the rubber composition for an inner liner according to claim 1.