Pneumatic tires

Abstract

To restrain the color change of a different color rubber layer in a pneumatic tire in which a different color rubber layer is exposed on the external face of a sidewall part.SOLUTION: A pneumatic tire includes a tread 2, a pair of sidewalls 3, a pair of beads 4, and a carcass 6. At least one of the pair of sidewalls 3 includes a first sidewall rubber 10. The first sidewall rubber 10 includes a base rubber layer 9, a different color rubber layer 11. and a barrier rubber layer 12. The base rubber layer 9 is in contact with the carcass 6. At least a part of the different color rubber layer 11 is exposed on the external face of the sidewall 3. The barrier rubber layer 12 is disposed between the different color rubber layer 11 and the base rubber layer 9, and has rubber compounding for inhibiting migration of the rubber compounding agent on the base rubber layer 9 side to the different color rubber layer 11. The thickness of the barrier rubber layer 12 is 1.0 mm or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] Patent Document 1 below proposes a pneumatic tire with a convex pattern formed on a sidewall portion. The pneumatic tire has a non-black rubber layer inside the sidewall portion, and a part of the non-black rubber layer is exposed on the raised surface of the convex pattern. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-203420 A Summary of the Invention [Problem to be solved by the invention]

[0004] The pneumatic tire of Patent Document 1 is expected to have an improved appearance due to the exposed different color rubber layer.

[0005] However, the different-color rubber layer has a problem in that rubber compounding agents such as antioxidants are easily transferred from the surrounding rubber members, causing discoloration. On the other hand, it is conceivable to dispose a barrier rubber layer having a rubber compounding capable of suppressing the transfer of the rubber compounding agents between the different-color rubber layer and the other rubber members. However, such a barrier rubber layer tends to be expensive and has low durability compared to the other rubber members.

[0006] The present invention has been devised in consideration of the above-described circumstances, and has as its main object to suppress discoloration of a different-color rubber layer in a pneumatic tire having a different-color rubber layer exposed on the outer surface of a sidewall portion, while maintaining tire manufacturing costs and durability. [Means for solving the problem]

[0007] The present invention is a pneumatic tire including a tread portion, a pair of sidewall portions, a pair of bead portions, and a carcass extending from one of the bead portions to the other of the bead portions, at least one of the pair of sidewall portions includes a first sidewall rubber arranged on the axially outer side of the carcass, the first sidewall rubber including a base rubber layer, a different color rubber layer, and a barrier rubber layer, the base rubber layer is in contact with the carcass, the different color rubber layer has a color different from a basic color of an outer surface of the sidewall portion, and at least a portion of the different color rubber layer is exposed to the outer surface of the sidewall portion, the barrier rubber layer is arranged between the different color rubber layer and the base rubber layer, and has a rubber compounding that suppresses migration of a rubber compounding agent on the base rubber layer side to the different color rubber layer, and the barrier rubber layer has a thickness of 1.0 mm or less.

[0008] In the pneumatic tire of the present invention, it is preferable that the pair of bead portions include clinch rubber constituting their respective outer surfaces, a portion of the barrier rubber layer is exposed on the outer surface of the sidewall portion, and a distance along the outer surface of the sidewall portion from an inner end of the barrier rubber layer in the tire radial direction to the clinch rubber is 10 to 30 mm.

[0009] In the pneumatic tire of the present invention, it is preferable that the first sidewall rubber includes a cover rubber layer that covers an outer surface of the different color rubber layer in the tire axial direction and exposes a part of the different color rubber layer, and that the cover rubber layer is composed of the same rubber compound as the barrier rubber layer.

[0010] In the pneumatic tire of the present invention, a boundary between a first outer surface vulcanized in a tread mold and a second outer surface vulcanized in a sidewall mold is included, and the different color rubber layer is arranged radially inward of the boundary, and in the tire meridian cross section, the distance from the boundary to the radial outer end of the different color rubber layer is desirably 10 to 30 mm.

[0011] In the pneumatic tire of the present invention, the different color rubber layer includes an exposed portion exposed to an outer surface of the sidewall portion, and the thickness of the different color rubber layer at a position 10 mm radially outward from the exposed portion is desirably 1.0 to 2.0 mm.

[0012] In the pneumatic tire of the present invention, the distance in the tire radial direction from the bead base line to the outer end in the tire radial direction of the barrier rubber layer is desirably 65% ​​or more of the section height.

[0013] In the pneumatic tire of the present invention, the section height is desirably 120 mm or less.

[0014] In the pneumatic tire of the present invention, it is desirable that the barrier rubber layer contains 60% or less of a butyl-based rubber. Effect of the Invention

[0015] By adopting the above configuration, the pneumatic tire of the present invention can suppress discoloration of the different color rubber layer while maintaining the manufacturing cost and durability of the tire. [Brief description of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing one embodiment of a tire of the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a sidewall portion of FIG. [Diagram 3] FIG. 3 is an enlarged view of the raised portion of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a pneumatic tire (hereinafter, sometimes simply referred to as "tire") 1 of this embodiment in a normal state. Note that FIG. 1 is a so-called tire meridian cross-sectional view including the tire's rotation axis. As shown in FIG. 1, the tire 1 of this embodiment is, for example, a tire for passenger cars, and is a relatively low-profile tire with a section height h1 of 120 mm or less. However, the present invention is not limited to this embodiment.

[0018] In the case of a pneumatic tire for which various standards are established, the "normal state" refers to a state in which the tire is mounted on a normal rim (not shown), inflated to the normal internal pressure, and no load is applied. In the case of a tire for which various standards are not established, the normal state refers to a standard use state according to the intended use of the tire, in which the tire is not mounted on a vehicle and no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal state.

[0019] A "genuine rim" is a rim that is defined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "Design Rim," and in the case of ETRTO, it is called a "Measuring Rim."

[0020] "Normal internal pressure" is the air pressure set for each tire by each standard in the standard system on which the tire is based. In the case of JATMA, it is the "maximum air pressure." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "INFLATION PRESSURE."

[0021] The section height h1 means the height in the radial direction of the tire 1 from the bead base line in the normal state. The bead base line is an axial line of the tire that passes through a rim diameter position determined by the standard on which the tire is based.

[0022] The tire 1 of this embodiment includes a tread portion 2, a pair of sidewall portions 3, a pair of bead portions 4, and a carcass 6 extending from one bead portion 4 to the other bead portion 4.

[0023] The carcass 6 is composed of, for example, two carcass plies 6A and 6B. The carcass plies 6A and 6B include, for example, a plurality of carcass cords and a topping rubber covering the same. The carcass cords are arranged at an angle of, for example, 75 to 90° with respect to the tire circumferential direction. For the carcass cords, organic fiber cords such as nylon, polyester, or rayon are preferably used.

[0024] The carcass 6 has a main body portion 6a and a turn-up portion 6b. The main body portion 6a extends between the bead cores 5 of the pair of bead portions 4. The turn-up portion 6b is continuous with the main body portion 6a and is turned-up around the bead core 5 to extend radially outward of the tire. The turn-up portion 6b in this embodiment is turned-up around the bead core 5 from the inner side to the outer side in the axial direction of the tire. In addition, in the turn-up portion 6b, the outer end of one carcass ply 6A and the outer end of the other carcass ply 6B are misaligned in the radial direction of the tire.

[0025] In the tread portion 2 of this embodiment, for example, a belt layer 7 is disposed on the tire radial outer side of the carcass 6. The belt layer 7 includes, for example, two belt plies 7A and 7B. Each of the belt plies 7A and 7B includes, for example, a belt cord disposed inclined with respect to the tire circumferential direction and a topping rubber covering the belt cord. Each belt cord is preferably inclined at an angle of 10 to 45° with respect to the tire circumferential direction.

[0026] The tread portion 2 includes a tread rubber 2G. The pair of bead portions 4 include clinch rubbers 15 constituting the outer surfaces thereof. At least one of the pair of sidewall portions 3 includes a first sidewall rubber 10 disposed on the axially outer side of the carcass 6.

[0027] 2 shows an enlarged cross-sectional view of the sidewall portion 3. As shown in FIG. 2, the first sidewall rubber 10 also includes a base rubber layer 9, a different color rubber layer 11, and a barrier rubber layer 12.

[0028] The base rubber layer 9 is in contact with the carcass 6, and constitutes a major portion of the first sidewall rubber 10. The base rubber layer 9 is preferably made of a conventional sidewall rubber material.

[0029] The different color rubber layer 11 has a color (white in this embodiment) different from the basic color of the outer surface of the sidewall portion 3 (black in this embodiment), and at least a part of it is exposed to the outer surface of the sidewall portion 3. In this embodiment, most of the different color rubber layer 11 is covered with the cover rubber layer 13 composed of the basic color, and a part of the different color rubber layer 11 is exposed so as to depict letters, marks, or figures.

[0030] FIG. 3 shows an enlarged cross-sectional view of a portion (raised portion) where the different-color rubber layer 11 is exposed. In this embodiment, the raised portion 20 is provided on the outer surface of the sidewall portion 3, and the different-color rubber layer 11 is exposed at a top surface 20t on the tire axially outer side. In the manufacturing method of the tire 1 of this embodiment, for example, a part of the sidewall portion 3 including the different-color rubber layer 11 covered with the cover rubber layer 13 is inserted into a corresponding recess of a vulcanization mold to form the raised portion 20, and then the top surface of the raised portion 20 is buffed so that the different-color rubber layer 11 is exposed. Such a manufacturing method is known and is suitably applied to the tire 1 of this embodiment. Note that FIG. 2 shows the side surface of the raised portion 20, not the cross section of the raised portion 20.

[0031] In the present invention, it is only necessary that the different color rubber layer 11 is exposed, and the present invention may be applied to a tire that does not include the above-mentioned raised portion 20.

[0032] As shown in Fig. 2, the barrier rubber layer 12 is disposed between the different color rubber layer 11 and the base rubber layer 9, and has a rubber compounding that suppresses the rubber compounding agents on the base rubber layer 9 side from migrating to the different color rubber layer 11. The thickness t1 of the barrier rubber layer 12 is 1.0 mm or less. By adopting the above-mentioned configuration in the present invention, discoloration of the different color rubber layer 11 can be suppressed while maintaining tire manufacturing costs and durability. The following mechanism is presumed to be the reason for this.

[0033] Conventionally, the different color rubber layer 11 has tended to discolor due to migration of rubber compounding agents such as antioxidants from the surrounding rubber members and also due to exposure to ultraviolet rays and the like, thereby impairing the appearance of the sidewall portion 3. In the present invention, the barrier rubber layer 12 is disposed between the different color rubber layer 11 and the base rubber layer 9, thereby making it possible to prevent the above-mentioned problems.

[0034] On the other hand, the rubber material constituting the barrier rubber layer 12 tends to be more expensive and less durable than conventional sidewall rubber. In the present invention, the thickness t1 of the barrier rubber layer 12 is limited to a small value of 1.0 mm or less, thereby making it possible to maintain tire manufacturing costs and durability.

[0035] A more detailed configuration of this embodiment will be described below. Each configuration described below shows a specific aspect of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-mentioned effects even if it does not have the configuration described below. In addition, even if any one of the configurations described below is applied alone to the tire of the present invention having the above-mentioned characteristics, an improvement in performance according to each configuration can be expected. Furthermore, when some of the configurations described below are applied in combination, a composite improvement in performance according to each configuration can be expected.

[0036] The base rubber layer 9 includes a portion in contact with the clinch rubber 15 of the bead portion 4. As a result, the barrier rubber layer 12 and the different color rubber layer 11 are spaced apart from the clinch rubber 15. The base rubber layer 9 also includes a portion in contact with the tread rubber 2G that constitutes the tread portion 2. As a result, the barrier rubber layer 12 and the different color rubber layer 11 are spaced apart from the tread rubber 2G.

[0037] In this embodiment, it is preferable that the axially outer end 2a of the tread rubber 2G is covered with the base rubber layer 9 of the first sidewall rubber 10. This improves durability in the vicinity of the boundary between the first sidewall rubber 10 and the tread rubber 2G.

[0038] The barrier rubber layer 12 is composed entirely of the same rubber compounding. The rubber compounding of the barrier rubber layer 12 contains, for example, butyl-based rubber. Butyl-based rubber exhibits extremely low air permeability and can effectively suppress migration of rubber compounding agents. On the other hand, if a rubber layer containing butyl-based rubber comes into contact with a rim, there is a risk of the rim corroding. From this perspective, the barrier rubber layer 12 preferably contains 60% or less butyl-based rubber, and more preferably contains 40% to 60% butyl-based rubber.

[0039] The barrier rubber layer 12 desirably contains an inorganic clay mineral such as kaolin clay, clay, mica, feldspar, or a hydrated complex of silica and alumina. This can further suppress the migration of the rubber compounding agents. A known rubber compounding can be applied to the barrier rubber layer 12 of the present invention.

[0040] The barrier rubber layer 12 preferably has a maximum thickness of 1.0 mm or less. From the viewpoint of reliably suppressing discoloration of the different color rubber layer 11 while maintaining tire manufacturing costs and durability, the maximum thickness of the barrier rubber layer 12 is more preferably 0.5 to 1.0 mm.

[0041] An inner end 12a and an outer end 12b of the barrier rubber layer 12 in the tire radial direction are each exposed to the outer surface of the tire 1. In the tire meridian cross section, a distance L1 from the inner end 12a of the barrier rubber layer 12 in the tire radial direction to the clinch rubber 15 along the outer surface of the sidewall portion 3 or the bead portion 4 is preferably 10 to 30 mm. This suppresses damage to the barrier rubber layer 12 near the inner end 12a in the tire radial direction.

[0042] The distance along the outer surface of the sidewall portion 3 from the tread ground contact edge Te to the radially outer end 12b of the barrier rubber layer 12 is desirably 20 mm or more. This suppresses damage near the radially outer end 12b of the barrier rubber layer 12. The tread ground contact edge Te corresponds to the axially outermost ground contact position of the tire when the tire 1 in the normal state is loaded with a normal load and contacts a flat surface with a camber angle of 0°.

[0043] In the case of a pneumatic tire for which various standards are established, the "normal load" is the load that each standard specifies for each tire in the standard system including the standard on which the tire is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. In addition, in the case of a tire for which various standards are not established, the "normal load" refers to the load acting on one tire in the standard mounting state of the tire. The "standard mounting state" refers to a state in which the tire is mounted on a standard vehicle corresponding to the intended use of the tire, and the vehicle is stationary on a flat road surface in a drivable state.

[0044] 1, the distance h2 in the tire radial direction from the bead base line to the outer end 12b of the barrier rubber layer 12 in the tire radial direction (hereinafter sometimes referred to as the height h2 of the barrier rubber layer 12) is preferably 65% ​​or more of the section height h1. In a more preferable embodiment, the height h2 of the barrier rubber layer 12 is 65% to 75% of the section height h1. This makes it possible to suppress stress concentration at the outer end 12b even when the sidewall portion 3 is deflected.

[0045] 2, the different-color rubber layer 11, except for the cover rubber layer 13 covering its outer surface, is in contact only with the barrier rubber layer 12 and is not in contact with other rubber members. This reliably prevents the rubber compounding ingredients from migrating.

[0046] The outer surface of the tire 1 includes a boundary 25 between a first outer surface 23 vulcanized in a tread mold and a second outer surface 24 vulcanized in a sidewall mold. In general, slight burrs tend to occur at the boundary 25 due to rubber entering the gap between the two molds. That is, the movement of rubber during vulcanization is large near the boundary 25. In a tire 1 having a relatively small section height as in the present embodiment, the boundary 25 and the different color rubber layer 11 are close to each other, and the movement of rubber near the boundary 25 may cause the different color rubber layer 11 to be exposed at unintended locations. To prevent such a problem, the different color rubber layer 11 is disposed on the inner side in the tire radial direction than the boundary 25. In addition, in the tire meridian cross section, the distance L2 from the boundary 25 to the outer end 11a in the tire radial direction of the different color rubber layer 11 is preferably, for example, 10 to 30 mm.

[0047] The different color rubber layer 11 includes an exposed portion that is exposed on the outer surface of the sidewall portion 3. As described above, in this embodiment, the exposed portion of the different color rubber layer 11 is configured on the top surface 20t of the raised portion 20. The thickness t2 of the different color rubber layer at a position 10 mm away from the exposed portion toward the outside in the tire radial direction is preferably 1.0 to 2.0 mm. This ensures a sufficient rubber volume of the different color rubber layer 11 around the exposed portion, improving the durability of the different color rubber layer 11.

[0048] The cover rubber layer 13 has a sufficient thickness to prevent the different color rubber layer 11 from being exposed in unnecessary places. On the other hand, if the cover rubber layer 13 is too thick, the workability of the buffing described above may decrease. From this viewpoint, the cover rubber layer 13 is desirably 0.5 to 1.0 mm.

[0049] In a more desirable embodiment, the cover rubber layer 13 is made of the same rubber compound as the barrier rubber layer 12. This makes it possible to suppress peeling of the cover rubber layer 13.

[0050] Although the preferred embodiments of the pneumatic tire of the present invention have been described in detail above, the present invention is not limited to the above specific embodiments and can be modified and practiced in various aspects. EXAMPLES

[0051] A pneumatic tire of size 225 / 50R18 having the basic structure of FIG. 1 was prototyped based on the specifications of Table 1. As Comparative Example 1, a pneumatic tire was prototyped in which a barrier rubber layer was not disposed between the base rubber layer and the different color rubber layer. As Comparative Example 2, a pneumatic tire was prototyped in which a barrier rubber layer having a thickness of 3.0 mm was disposed between the base rubber layer and the different color rubber layer. The tires of Comparative Examples 1 and 2 have substantially the same configuration as the tire of the Example, except for the above-mentioned points. For each test tire, the discoloration resistance performance of the different color rubber layer, the cost of the first sidewall rubber, and the durability of the exposed part of the different color rubber layer were tested. The common specifications and test methods of each test tire are as follows. Rim: 18×7.0J Tire pressure: 220kPa

[0052] <Discoloration resistance of different color rubber layers> The test tire was run for 18 hours at a speed of 80 km / h on a drum tester with a constant vertical load. During this run, ultraviolet light was continuously irradiated using a black light on the exposed part of the different-colored rubber layer on the sidewall. After the run, the degree of discoloration of the exposed part of the different-colored rubber layer was visually evaluated. The results were shown on a 5-point scale from 1 to 5, with a higher score indicating better discoloration resistance.

[0053] <First sidewall rubber cost> The cost of manufacturing the first sidewall rubber was calculated. The results were shown on a 5-point scale from 1 to 5, with a higher score indicating a lower cost and better performance of the first sidewall rubber.

[0054] <Durability of exposed areas of different color rubber layers> The test tire was loaded with a constant vertical load on a drum testing machine and run for 15,000 km at a speed of 80 km / h, after which the degree of damage to the exposed portion of the different-colored rubber layer was visually evaluated. The results were shown as a score based on the degree of damage in Comparative Example 1 being 100, with a higher score indicating better durability of the exposed portion of the different-colored rubber layer. The test results are shown in Table 1.

[0055] [Table 1]

[0056] As a result of the test, it was confirmed that the tires of the examples suppressed discoloration of the different-color rubber layer while maintaining tire manufacturing costs and durability. [Explanation of symbols]

[0057] 2 Tread section 3 Sidewall 4 Bead section 6. Carcass 9 Base rubber layer 10 First sidewall rubber 11 Different color rubber layer 12 Barrier rubber layer

Claims

1. A pneumatic tire, The tire includes a tread portion, a pair of sidewall portions, a pair of bead portions, and a carcass extending from one of the bead portions to the other of the bead portions, At least one of the pair of sidewall portions includes a first sidewall rubber disposed axially outward of the carcass, The first sidewall rubber includes a base rubber layer, a different color rubber layer, and a barrier rubber layer, The base rubber layer is in contact with the carcass, the different color rubber layer has a color different from a basic color of the outer surface of the sidewall portion, and at least a part of the different color rubber layer is exposed to the outer surface of the sidewall portion, the barrier rubber layer is disposed between the different-color rubber layer and the base rubber layer, and has a rubber compounding that suppresses migration of a rubber compounding agent of the base rubber layer to the different-color rubber layer, The barrier rubber layer has a thickness of 1.0 mm or less, The pair of bead portions each include a clinch rubber that configures an outer surface of the pair of bead portions, a portion of the barrier rubber layer is exposed to an outer surface of the sidewall portion, On the outer surface of the sidewall portion, a distance along the outer surface of the sidewall portion from an inner end of the barrier rubber layer in the tire radial direction to the clinch rubber is 10 to 30 mm. Pneumatic tires.

2. A pneumatic tire, The tire includes a tread portion, a pair of sidewall portions, a pair of bead portions, and a carcass extending from one of the bead portions to the other of the bead portions, At least one of the pair of sidewall portions includes a first sidewall rubber disposed axially outward of the carcass, The first sidewall rubber includes a base rubber layer, a different color rubber layer, and a barrier rubber layer, The base rubber layer is in contact with the carcass, the different color rubber layer has a color different from a basic color of the outer surface of the sidewall portion, and at least a part of the different color rubber layer is exposed to the outer surface of the sidewall portion, the barrier rubber layer is disposed between the different-color rubber layer and the base rubber layer, and has a rubber compounding that suppresses migration of a rubber compounding agent of the base rubber layer to the different-color rubber layer, The barrier rubber layer has a thickness of 1.0 mm or less, The tire includes a boundary between a first outer surface vulcanized and molded in a tread mold and a second outer surface vulcanized and molded in a sidewall mold, the different color rubber layer is disposed radially inward of the boundary, In a tire meridian cross section, a distance from the boundary to an outer end of the different color rubber layer in a tire radial direction is 10 to 30 mm. Pneumatic tires.

3. A pneumatic tire, The tire includes a tread portion, a pair of sidewall portions, a pair of bead portions, and a carcass extending from one of the bead portions to the other of the bead portions, At least one of the pair of sidewall portions includes a first sidewall rubber disposed axially outward of the carcass, The first sidewall rubber includes a base rubber layer, a different color rubber layer, and a barrier rubber layer, The base rubber layer is in contact with the carcass, the different color rubber layer has a color different from a basic color of the outer surface of the sidewall portion, and at least a part of the different color rubber layer is exposed to the outer surface of the sidewall portion, the barrier rubber layer is disposed between the different-color rubber layer and the base rubber layer, and has a rubber compounding that suppresses migration of a rubber compounding agent of the base rubber layer to the different-color rubber layer, The barrier rubber layer has a thickness of 1.0 mm or less, the different color rubber layer includes an exposed portion that is exposed to an outer surface of the sidewall portion, The thickness of the different color rubber layer at a position 10 mm away from the exposed portion in the tire radial direction outward is 1.0 to 2.0 mm. Pneumatic tires.

4. A pneumatic tire, The tire includes a tread portion, a pair of sidewall portions, a pair of bead portions, and a carcass extending from one of the bead portions to the other of the bead portions, At least one of the pair of sidewall portions includes a first sidewall rubber disposed axially outward of the carcass, The first sidewall rubber includes a base rubber layer, a different color rubber layer, and a barrier rubber layer, The base rubber layer is in contact with the carcass, the different color rubber layer has a color different from a basic color of the outer surface of the sidewall portion, and at least a part of the different color rubber layer is exposed to the outer surface of the sidewall portion, the barrier rubber layer is disposed between the different-color rubber layer and the base rubber layer, and has a rubber compounding that suppresses migration of a rubber compounding agent of the base rubber layer to the different-color rubber layer, The barrier rubber layer has a thickness of 1.0 mm or less, A distance in a radial direction of the tire from a bead base line to an outer end in a radial direction of the barrier rubber layer is 65% or more of a section height. Pneumatic tires.

5. The first sidewall rubber includes a cover rubber layer covering an outer surface of the different-color rubber layer in the tire axial direction and exposing a part of the different-color rubber layer, The pneumatic tire according to claim 1 , wherein the cover rubber layer is formed of the same rubber compound as the barrier rubber layer.

6. A pneumatic tire described in any one of claims 1 to 5, having a section height of 120 mm or less.

7. A pneumatic tire as described in any one of claims 1 to 6, wherein the barrier rubber layer contains 60% or less of butyl-based rubber.

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