tire

Abstract

The present invention provides a tire with low rolling resistance, low electrical resistance, and the ability to suppress the occurrence of defects when the unvulcanized rubber of the inner liner is processed into a sheet. [Solution] The tie rubber 10 is positioned between the carcass 4 and the inner liner 9 and extends along the carcass between the bead cores 5. The inner liner and the tie rubber each contain carbon black. With respect to the specific surface area × mass fraction (IL), which is the product of the CTAB adsorption specific surface area of ​​the carbon black contained in the inner liner and the mass fraction of the carbon black in the rubber composition, and the specific surface area × mass fraction (TR), which is the product of the CTAB adsorption specific surface area of ​​the carbon black contained in the tie rubber and the mass fraction of the carbon black in the rubber composition, the specific surface area × mass fraction (IL) + specific surface area × mass fraction (TR) > 20, and 5

Description

[Technical Field]

[0001] The present invention relates to a tire in which an inner liner extends along the carcass. [Background technology]

[0002] To reduce environmental impact, there is a demand for improved vehicle fuel efficiency. Therefore, tires are required to generate less heat during rolling and have low rolling resistance. To reduce tire heat generation, for example, reducing the amount of carbon black in the rubber composition of each part of the tire is effective. In recent years, research has been conducted to further improve fuel efficiency by suppressing heat generation in all parts of the tire except for the tread rubber that contacts the road surface.

[0003] On the other hand, as tire heat generation decreases, the amount of carbon black used in the compound decreases, which leads to the problem of increased electrical resistance in the tire. High electrical resistance in tires makes it difficult for static electricity accumulated in the vehicle to discharge to the road surface, which can cause problems such as noise in the radio (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-237337 [Overview of the project] [Problems that the invention aims to solve]

[0005] On the other hand, as carbon black content has decreased, problems such as holes appearing in the sheet may occur when the unvulcanized rubber of various parts of the tire is rolled and processed into a sheet. For example, if there are holes in the inner liner, the gas barrier properties of the tire will decrease, impairing its ability to maintain proper air pressure.

[0006] The present invention aims to provide a tire that has low rolling resistance, low electrical resistance, and can suppress the occurrence of defects when the unvulcanized rubber used as the inner liner is processed into a sheet. [Means for solving the problem]

[0007] This disclosure includes the following aspects: Appearance [1] It is a tire, A pair of annular bead cores, A carcass is stretched between the bead cores in a toroidal shape, An inner liner is positioned on the inside of the tire relative to the carcass and extends along the carcass between the bead cores, The system comprises a tie rubber positioned between the carcass and the inner liner, and extending along the carcass between the bead cores, The inner liner and the tie rubber each consist of a rubber composition containing carbon black. The CTAB adsorption specific surface area of ​​the carbon black contained in the inner liner [m²] 2 The specific surface area × mass fraction (IL), which is the product of [ / g] and the mass fraction of the carbon black in the rubber composition, and the CTAB adsorption specific surface area [m²] of the carbon black contained in the rubber. 2 With respect to the specific surface area × mass fraction (TR), which is the product of [ / g] and the mass fraction of the carbon black in the rubber composition, Specific surface area × mass fraction (IL) + specific surface area × mass fraction (TR) > 20, A tire characterized by the condition that 5 < specific surface area × mass fraction (IL) < 12.

[0008] Appearance [2] A tire according to embodiment [1], satisfying the conditions 20 < specific surface area × mass fraction (TR) < 40.

[0009] Appearance [3] The tire according to aspect [1] or [2], wherein the tread rubber contains 65 to 95 parts by mass of isoprene rubber per 100 parts by mass of the rubber component contained in the tread rubber.

[0010] Aspect [4] The tread rubber contains, per 100 parts by mass of the rubber component contained in the tread rubber, 5 to 40 parts by mass of carbon black (A) having a CTAB adsorption specific surface area of 25 to 50 m 2 / g and 20 to 80 parts by mass of carbon black (B) having a CTAB adsorption specific surface area of 70 to 130 m 2 / g, and In the tire according to any one of aspects [1] to [3], the total content of the carbon black (A) and the carbon black (B) is 35 parts by mass or more per 100 parts by mass of the rubber component contained in the tread rubber.

Advantages of the Invention

[0011] According to the tire of the above aspect, the rolling resistance is small, the electrical resistance is small, and the occurrence of defects when the unvulcanized rubber serving as the inner liner is processed into a sheet can be suppressed.

Brief Description of the Drawings

[0012] [Figure 1] It is a view showing a meridian cross section of a tire of one embodiment.

Mode for Carrying Out the Invention

[0013] Hereinafter, the tire of the embodiment will be described in detail. The tire of the present invention is preferably a tire for filling internal pressure such as a pneumatic tire. The tire of the present embodiment is a pneumatic tire. The cavity region surrounded by the rim and the tire for filling internal pressure mounted on the rim can be filled with air, an inert gas such as nitrogen, or other gases.

[0014] FIG. 1 is a view showing a meridian cross section of a tire according to the present embodiment. The tire according to the present embodiment includes a tread portion 1 that extends in the tire circumferential direction and forms an annular shape, a pair of sidewall portions 2 disposed on both sides of the tread portion 1 in the tire width direction, and a pair of bead portions 3 disposed on the inner side in the tire radial direction of the sidewall portion 2. In FIG. 1, CL indicates the tire center line.

[0015] Each of the bead portions 3 has, for example, an annular bead core 5 having a structure in which a plurality of steel wires coated with rubber are wound around the tire circumferential direction a plurality of times.

[0016] The carcass 4 is bridged over the pair of bead cores 5 so as to form a toroidal shape, extends between the bead cores 5, and is folded back from the inner side to the outer side in the tire width direction around the bead cores 5. The carcass 4 is formed by covering a plurality of reinforcing cords aligned to extend in the tire radial direction with rubber. The reinforcing cords are made of organic fibers such as PET fibers.

[0017] A bead filler 6 is disposed on the outer side in the tire radial direction of the bead core 5. The bead filler 6 is wrapped by a portion of the carcass 4 folded back around the bead core 5.

[0018] In the tread portion 1, a plurality of layers (two layers in the example shown in FIG. 1) of belts 7 are embedded on the outer side in the tire radial direction of the carcass 4. The belt 7 includes a plurality of reinforcing cords (for example, steel cords) inclined with respect to the tire circumferential direction, and is arranged such that the inclination directions of the reinforcing cords with respect to the tire circumferential direction intersect each other between the layers. The inclination angle of the reinforcing cords of each belt 7 with respect to the tire circumferential direction is, for example, 10° to 40°.

[0019] A belt cover 8 is provided on the outer side of the upper layer (outer side in the tire radial direction) belt 7 in the tire radial direction. In the example shown in Figure 1, multiple layers of belt covers 8 are provided, consisting of a lower layer (inner side in the tire radial direction) belt cover 8 that covers the entire area of ​​the belt 7 in the tire width direction, and a pair of upper layers of belt covers 8 that cover both ends of the lower layer belt cover 8 in the tire width direction. The belt cover 8 includes organic fiber cords oriented in the tire circumferential direction. The inclination angle of the organic fiber cords of the belt cover 8 with respect to the tire circumferential direction is, for example, 0° to 5°.

[0020] An inner liner 9 is provided on the surface of the tire facing the side of the cavity region between the tire and the rim (the inner side of the tire). The inner liner 9 is positioned on the inner side of the tire relative to the carcass 4 and is a rubber that extends along the carcass 4 between a pair of bead cores 5. The inner liner 9 is composed of a rubber composition mainly of butyl rubber (IIR). The end of the inner liner 9 on the bead core 5 side is preferably in contact with the rim cushion rubber 30, which will be described later, as shown in Figure 1.

[0021] A tie rubber 10 is positioned between the carcass 4 and the inner liner 9. The tie rubber 10 is a rubber that is sandwiched between the carcass 4 and the inner liner 9 and extends along the carcass 4 between the pair of bead cores 5. When conductive rubber, described later, is provided on the tread portion 1, it is preferable that the tie rubber 10 extends at least from the bead core 5 side to a position beyond a straight line that extends in the tire radial direction, passing through the inner end of the conductive rubber in the tire radial direction. With a tie rubber 10 of this form, a path for electricity to flow between the rim and the road surface is easily secured. It is preferable that both ends of the tie rubber 10 on the bead core 5 side are in contact with the rim cushion rubber 30. In the example shown in Figure 1, the ends of the inner liner 9 and tie rubber 10 on the bead core 5 side are sandwiched between the carcass 4 and the rim cushion rubber 30 on the inner side of the bead core 5 in the tire radial direction.

[0022] The tread portion 1 has tread rubber 11 positioned radially outward of the carcass 4. The tread rubber 11 in the example shown in Figure 1 has a cap tread rubber 12 that has a contact surface that contacts the road surface, and an under tread rubber 13 positioned radially inward of the cap tread rubber 12. The under tread rubber 13 is in contact with the cap tread rubber 12 and the belt cover 8.

[0023] Preferably, the tread rubber 11 has a conductive rubber (also called earth tread rubber) embedded in it, which is not shown. The conductive rubber is in contact with the belt 7, or in the example shown in Figure 1, with the belt cover 8, and penetrates the tread rubber 11 in the tire radial direction to be exposed on the contact surface. The conductive rubber, for example, runs around the tire circumferentially along the tire center line CL, and its length in the tire width direction is, for example, 1 to 5 mm. The conductive rubber is made of a rubber composition containing carbon black, with the carbon black being, for example, 40 to 80 parts by mass per 100 parts by mass of the rubber components contained in the rubber composition.

[0024] In the sidewall section 2, the side rubber 20 is positioned on the outer side in the tire width direction of the carcass 4.

[0025] In the bead section 3, a rim cushion rubber 30 is arranged around the carcass 4 and in contact with the rim.

[0026] The inner liner 9 and the tie rubber 10 are each made of a rubber composition containing carbon black. Such inner liner 9 and tie rubber 10 function as parallel paths for electricity to flow between the rim and the road surface, contributing to reducing the electrical resistance of the tire.

[0027] The specific surface area of ​​carbon black containing inner liner 9 that adsorbs CTAB (n-hexadecyltrimethylammonium bromide) [m² 2 The specific surface area × mass fraction (IL) [m²] is the product of the mass fraction [parts / parts] of carbon black in the rubber composition of the inner liner 9 and the mass fraction [m²] of carbon black. 2[g], and the specific surface area of ​​carbon black adsorption [m²] of the CTAB contained in the rubber 10. 2 The specific surface area × mass fraction (TR) [m²] is the product of the mass fraction [parts / parts] of carbon black in the rubber composition of Thai Rubber 10. 2 Regarding / g], the tire of this embodiment is given by the following formula (1): Specific surface area x mass fraction (IL) + specific surface area x mass fraction (TR)>20...(1) Satisfying the conditions, The following equation (2): 5<specific surface area x mass fraction (IL)<12...(2) The following conditions are met. In this specification, the CTAB adsorption specific surface area of ​​carbon black is a value measured in accordance with JIS K6217-3.

[0028] According to the inventors' research, the ease with which various parts of a tire generate heat and the magnitude of its electrical resistance are strongly correlated with the magnitude of the product between the specific surface area of ​​CTAB adsorption of carbon black contained in each part of the tire and the mass fraction of carbon black in the rubber composition. It was found that a larger product value leads to easier heat generation, while a smaller product value leads to increased electrical resistance. Based on this finding, even if the amount of carbon black in each part of the tire is small, if the particle size of the carbon black is too small, the above product value will be large, and heat generation cannot be sufficiently suppressed. Conversely, even if the amount of carbon black in each part of the tire is large, if the particle size of the carbon black is too large, the above product value will be small, and electrical resistance cannot be sufficiently reduced. It is thought that when the particle size of carbon black is large, the spacing between particles becomes wider compared to when the particle size of carbon black is small, even if the above product value is the same, resulting in increased electrical resistance.

[0029] The inner liner 9 is located on the innermost part of the tire and is usually thicker than the tire rubber 10. Therefore, it is prone to significant deformation due to flexing during rolling and is easily heated. For this reason, in the tire of this embodiment, the specific surface area × mass fraction (IL) is limited to less than 12, as shown in equation (2). If the specific surface area × mass fraction (IL) is 12 or more, the inner liner 9 is prone to heating up, and the rolling resistance of the tire cannot be reduced. In the tire of this embodiment, as shown in equation (1), the sum of specific surface area × mass fraction (IL) and specific surface area × mass fraction (TR) is greater than 20, thus ensuring the ease of electrical flow in parallel paths and reducing the electrical resistance of the tire. In particular, the tie rubber 10 is usually thinner than the inner liner 9 and has little effect on the tire characteristics, making it suitable as a path to ensure the ease of electrical flow. On the other hand, if the specific surface area × mass fraction (IL) is too small, problems such as holes appearing in the sheet occur when the unvulcanized rubber that becomes the inner liner 9 is rolled and processed into a sheet. For this reason, as shown in equation (2), the specific surface area × mass fraction (IL) is limited to a value greater than 5. If the specific surface area × mass fraction (IL) is 5 or less, the stress generated by rolling in the unvulcanized rubber sheet that becomes the inner liner 9 is not easily relieved, and problems such as holes appearing in the sheet occur.

[0030] Therefore, according to the tire of this embodiment, by satisfying equations (1) and (2), rolling resistance is low, electrical resistance is low, and the occurrence of defects when the unvulcanized rubber that forms the inner liner 9 is processed into a sheet can be suppressed. As a result, even in a tire with low rolling resistance, where the amount of carbon black in each part of the tire excluding the cap tread rubber 12 is small, electrical resistance can be effectively reduced.

[0031] For equation (1), the value of specific surface area × mass fraction (IL) + specific surface area × mass fraction (TR) is preferably 25 or more, and more preferably 30 or more. On the other hand, the value of specific surface area × mass fraction (IL) + specific surface area × mass fraction (TR) is preferably 60 or less, and more preferably 40 or less.

[0032] For equation (2), the specific surface area × mass fraction (IL) is preferably 6 to 9.

[0033] According to one embodiment, it is preferable that the specific surface area × mass fraction (IL) is smaller than the specific surface area × mass fraction (TR).

[0034] Furthermore, according to one embodiment, the thickness of the tie rubber 10 is preferably thinner than the thickness of the inner liner 9, and more preferably 0.3 to 0.8 times the thickness of the inner liner 9. The thickness of the tie rubber 10 is preferably 0.05 to 0.6 mm. The thickness of the inner liner 9 is preferably 0.3 to 1.2 mm.

[0035] The tire of this embodiment is given by the following formula (3): 20<specific surface area x mass fraction (TR)<40...(3) It is preferable that the following conditions are met. If the specific surface area × mass fraction (TR) exceeds 20, the electrical resistance of the tire tends to be low. If the specific surface area × mass fraction (TR) is less than 40, the rolling resistance of the tire tends to be low. The specific surface area × mass fraction (TR) is preferably 23 to 29.

[0036] It is preferable that the Thai Rubber 10 contains 65 to 95 parts by mass of isoprene-based rubber in 100 parts by mass of the rubber components in the rubber composition of the Thai Rubber 10. When the amount of isoprene-based rubber is 65 parts by mass or more in 100 parts by mass of the rubber components, the break elongation of the Thai Rubber 10 tends to improve, and the durability of the tire tends to improve. Furthermore, when the amount of isoprene-based rubber is 95 parts by mass or less in 100 parts by mass of the rubber components, defects such as holes forming in the unvulcanized rubber sheet of the rolled Thai Rubber 10 tend to be suppressed. It is more preferable that the Thai Rubber 10 contains 77 to 89 parts by mass of isoprene-based rubber in 100 parts by mass of the rubber components. Isoprene-based rubber is, for example, natural rubber (NR). Specifically, the rubber components contained in the rubber composition of the Thai Rubber 10 are diene-based rubbers. In addition to isoprene-based rubber, the Thai Rubber 10 may further contain styrene-butadiene rubber (SBR), butadiene rubber (BR), etc., as rubber components.

[0037] The inner liner 9 preferably contains 70 to 100 parts by mass of butyl rubber (IIR) per 100 parts by mass of the rubber component contained in the rubber composition of the inner liner 9. The rubber component contained in the rubber composition of the inner liner rubber 9 is specifically a diene rubber. The inner liner 9 may contain, as the rubber component, in addition to butyl rubber (IIR), rubbers such as isoprene rubber and styrene butadiene rubber (SBR).

[0038] The tread rubber 10 has, as carbon black, 5 to 40 parts by mass of carbon black (A) having a CTAB adsorption specific surface area of 25 to 50 m 2 / g and 20 to 80 parts by mass of carbon black (B) having a CTAB adsorption specific surface area of 70 to 130 m 2 / g, and it is preferable that the total content of carbon black (A) and carbon black (B) is 35 parts by mass or more. By the tread rubber 10 containing carbon black (A) having a large particle size in addition to carbon black (B) having a small particle size in the above content, the rolling resistance of the tire is likely to be smaller than in the case of containing only carbon black (B) in the above content. Examples of carbon black (A) include those of the GPF and FEF grades. Examples of carbon black (B) include those of the HAF and ISAF grades. The total content of carbon black (A) and carbon black (B) is preferably 40 parts by mass or more, and more preferably 65 parts by mass or less, per 100 parts by mass of the rubber component contained in the rubber composition of the tread rubber 10.

[0039] In addition, when the rubber composition contains carbon blacks having a plurality of types of CTAB adsorption specific surface areas, the specific surface area × mass fraction is calculated as, for example, a weighted average value weighted by the mass fraction of each carbon black in the rubber composition.

[0040] The CTAB adsorption specific surface area of the carbon black in the rubber composition of the inner liner 9 is preferably 25 to 50 m 2The amount is / g, and for example, a GPF grade is used. In addition, the carbon black content in the rubber composition of the inner liner 9 is preferably 5 to 50 parts by mass per 100 parts by mass of the rubber component.

[0041] The rubber compositions of Thai Rubber 10 and Inner Liner 9 preferably contain, in addition to rubber components and carbon black, compounding agents such as oil, stearic acid, zinc oxide, sulfur, and vulcanization accelerators. The rubber composition of Inner Liner 9 preferably further contains resin as a compounding agent. The rubber composition of Inner Liner 9 preferably further contains an anti-aging agent as a compounding agent. On the other hand, the rubber composition of Thai Rubber 10 preferably does not contain surfactants such as nonionic surfactants. If surfactants are included, the viscosity of the unvulcanized rubber composition decreases, requiring more time for mixing. Also, the decrease in viscosity may cause adhesion to the mixing equipment.

[0042] Preferably, the tie rubber 10 and inner liner 9 are made from two layers of unvulcanized rubber sheets laminated together, with the width of the tie rubber 10 being longer than the width of the inner liner 9. With this configuration, it is less likely that air will enter and remain inside the tire when manufacturing the unvulcanized tire. In addition, the inner liner 9 can be well adhered to the carcass 4 via the tie rubber 10. Furthermore, it is possible to prevent the rubber of the inner liner 9 from being pressed against the reinforcing cords of the carcass 4 and lifting up onto the inner surface of the tire.

[0043] (Examples, Comparative Examples) To verify the effectiveness of the tire of this embodiment, vulcanized test tires with a tire size of 235 / 60R18 and the basic structure shown in Figure 1 were manufactured by varying the specifications of the rubber composition of the tie rubber and inner liner (Comparative Example, Example), and the electrical resistance, rolling resistance, durability, and the degree of sheet defect occurrence (rollable sheet processability) when the unvulcanized rubber that becomes the inner liner and tie rubber is rolled and processed into a sheet were evaluated.

[0044] The specifications for carbon blacks CB1 to CB4, shown in Tables 4 and 5, are as follows:

[0045] [Table 1]

[0046] The common raw material formulations for the Thai rubber TR1 to TR9 rubber compositions shown in Tables 4 and 5 are as shown in Table 2 below. The values ​​in the table represent parts by mass per 100 parts by mass of rubber component.

[0047] [Table 2]

[0048] The raw material formulations for the rubber compositions of inner liners IL1 to IL3, shown in Tables 4 and 5, are as shown in Table 3 below. The values ​​in the table represent parts by mass per 100 parts by mass of rubber component.

[0049] [Table 3]

[0050] Other ingredients listed in the table are as follows: • NR: TSR20 • SBR: Zeon Corporation SBR1502 • IIR: ExxonMobil Bromobutyl 2255 • Oil: Idemitsu Kosan Co., Ltd. Diana Process NH-70S • Anti-aging agent: Nocrack 6C, manufactured by Ouchi Shinko Chemical Co., Ltd. • Petroleum-based resin: Hitanol 1502Z, Hitachi Chemical Co., Ltd. • Stearic acid: Nisshin Rika Co., Ltd. Stearic acid 50S • Zinc oxide: Three types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd. • Insoluble sulfur: Micron OT-20 manufactured by Shikoku Chemicals, Inc. • Vulcanization accelerator: Sanshin Chemical Industry Co., Ltd. Sunceller NS-G

[0051] The values ​​for raw materials in Tables 4 and 5 represent parts by mass per 100 parts by mass of rubber component. Tables 4 and 5 only show the rubber component and carbon black among the raw materials for the inner liner and tie rubber rubber compositions. In the tables, "IL" refers to the inner liner and "TR" refers to the tie rubber. The specific surface area × mass fraction (total) shown as an index in Tables 4 and 5 represents the sum of specific surface area × mass fraction (IL) and specific surface area × mass fraction (TR). The unit of specific surface area × mass fraction is (m²). 2 It is ( / g)·(parts of mass / parts of mass). The specific surface area × mass fraction of a rubber composition containing two types of carbon black A and B with different specific surface areas is given by the following formula: {(Specific surface area of ​​carbon black A adsorbing CTAB) × (Mass parts of carbon black A)} + (Specific surface area of ​​carbon black B adsorbing CTAB) × (Mass portion of carbon black B) / parts of mass of rubber composition The calculation was performed according to the following method.

[0052] In each test tire, the tie rubber thickness was set to 0.3 mm and the inner liner thickness to 0.6 mm. Note that the thickness of the tie rubber and inner liner after vulcanization during the tire molding process is thinner than before vulcanization. The rubber composition of each part of the tire, excluding the inner liner and tie rubber, was a composition commonly used in fuel-efficient tires. Conductive rubber was provided on the tire center line CL in the tread area.

[0053] Electrical resistance, rolling resistance, rollable sheet processability, and durability were evaluated according to the following procedure.

[0054] (Electrical resistance) In an environment with a temperature of 23°C and humidity of 50%, a test tire was mounted on a wheel with a rim size of 18×7J. Under conditions of air pressure of 200kPa and load of 5.26kN, a voltage of 1000V was applied to the wheel, and after 5 minutes, the electrical resistance [Ω] between the tread surface and the rim was measured. Measurements were taken at three points on the circumference of the tire, and the average value was calculated. In the table, the part of the value raised to the power of 10 to the power of n (where n is a natural number) is shown as the electrical resistance [Ω], denoted as "10^n". A smaller n indicates lower electrical resistance, superior discharge performance, and superior anti-static performance of the tire.

[0055] (Rolling resistance) The test tire was mounted on a wheel with a rim size of 18 x 7J, and the rolling resistance was measured using an indoor drum testing machine (drum diameter: 1707.6 mm) in accordance with ISO 28580, under conditions of air pressure of 210 kPa, load of 4.82 kN, and speed of 80 km / h. The measured value was expressed as an index with Comparative Example 1 set to 100. A smaller index value indicates lower rolling resistance and better fuel efficiency for the vehicle. An index value of 104 or less ensures low rolling resistance.

[0056] (Processability of rolled sheets) The unvulcanized rubber used for the inner liner and tie rubber of the test tire was rolled into sheets and processed. The degree of defects within a 100m length area of ​​the sheet in the longitudinal direction was investigated. Sheets with through holes of 1mm or more in diameter (maximum length) were evaluated as "defective," sheets without holes of 1mm or more in diameter but with roughness such as unevenness on the sheet surface were evaluated as "acceptable," and sheets that did not fall into any of the above categories were evaluated as "good." The thickness of the unvulcanized rubber sheets was set to 0.8mm for the inner liner and 0.5mm for the tie rubber.

[0057] Based on the above results, the electrical resistance value in the table is 10 7 Materials with a rolling resistance index smaller than Ω, a rolling resistance index of 104 or less, and rollability of the inner liner into a sheet were evaluated as having low rolling resistance, low electrical resistance, and suppressing the occurrence of defects when the unvulcanized rubber used as the inner liner was processed into a sheet.

[0058] (durability) The tires were inflated to an air pressure of 120 kPa, mounted on an indoor drum testing machine (drum diameter: 1707.6 mm), subjected to a load of 8.58 kN, and driven at a speed of 81 km / h until tire failure occurred. The driving distance was expressed as an index, with the driving distance of Comparative Example 1 set to 100. A higher index value indicates superior durability.

[0059] [Table 4]

[0060] [Table 5]

[0061] A comparison of the examples and comparative examples shows that satisfying equations (1) and (2) with respect to specific surface area × mass fraction (IL) and specific surface area × mass fraction (TR) results in low rolling resistance, low electrical resistance, and suppression of defects when the unvulcanized rubber used as the inner liner is processed into a sheet.

[0062] A comparison of Examples 2 and 3 with Examples 1 and 4 shows that satisfying equation (3) with respect to specific surface area × mass fraction (TR) results in the effect of reducing both rolling resistance and electrical resistance. A comparison of Example 5 with Examples 2 and 6 shows that when the isoprene-based rubber in the tie rubber is contained in an amount of 65 to 95 parts by mass per 100 parts by mass of rubber component, the durability of the tire is improved, while the occurrence of defects when the unvulcanized rubber of the tie rubber is processed into a sheet is suppressed. A comparison of Examples 7 and 8 with Example 2 shows that including predetermined amounts of two types of carbon black with different CTAB adsorption specific surface areas in the tie rubber significantly reduces rolling resistance.

[0063] Although the tire of the present invention has been described in detail above, the tire of the present invention is not limited to the above embodiments or examples, and various improvements and modifications may be made without departing from the spirit of the present invention. [Explanation of Symbols]

[0064] 1. Tread section 2 Sidewall section 3. Bead section 4 Carcass 5 Bead core 6. Bead Filler 7 belts 8 Belt cover 9 Inner Liner 10 Thai rubber 11 Tread Rubber 12 Cap Tread Rubber 13 Undertread Rubber 20 Side rubber 30 Rim cushion rubber

Claims

1. It is a tire, A pair of annular bead cores, A carcass is stretched between the bead cores in a toroidal shape, An inner liner is positioned on the inside of the tire relative to the carcass and extends along the carcass between the bead cores, The system comprises a tie rubber positioned between the carcass and the inner liner, and extending along the carcass between the bead cores, The inner liner and the tie rubber each consist of a rubber composition containing carbon black. The CTAB adsorption specific surface area of ​​the carbon black contained in the inner liner [m²] 2 The specific surface area × mass fraction (IL), which is the product of the carbon black / g and the mass fraction of the carbon black in the rubber composition, and the CTAB adsorption specific surface area [m²] of the carbon black contained in the rubber, and 2 With respect to the specific surface area × mass fraction (TR), which is the product of [ / g] and the mass fraction of the carbon black in the rubber composition, Specific surface area × mass fraction (IL) + specific surface area × mass fraction (TR) > 20, A tire characterized in that 5 < specific surface area × mass fraction (IL) < 12.

2. The tire according to claim 1, satisfying 20 < specific surface area × mass fraction (TR) < 40.

3. The tire according to claim 1 or 2, wherein the tie rubber contains 65 to 95 parts by mass of isoprene-based rubber in 100 parts by mass of the rubber component contained in the tie rubber.

4. The aforementioned tie rubber contains 100 parts by mass of rubber component, with the carbon black having a CTAB adsorption specific surface area of ​​25 to 50 m². 2 5 to 40 parts by mass of carbon black (A) at a concentration of / g, and CTAB adsorption specific surface area of ​​70 to 130 m² 2 It contains 20 to 80 parts by mass of carbon black (B) at a concentration of / g, The tire according to claim 1 or 2, wherein the total content of carbon black (A) and carbon black (B) is 35 parts by mass or more per 100 parts by mass of rubber component contained in the tire rubber.

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