WO2020095891A1 - Run-flat tire - Google Patents

Abstract

This run-flat tire is provided with: a pair of bead cores; a carcass that is provided across the pair of bead cores and that has ends locked with the bead cores; an inner liner provided on the tire inner surface side of the carcass and that has a diene rubber content not less than 20 mass% with respect to the total amount of rubber included in the inner liner; a side-reinforcing rubber layer that is provided between the inner liner and the carcass at the tire side portions so as to be in direct contact with the inner liner, and that extends in the tire radial direction along the inner surface of the carcass; and a belt layer that is provided outward in the tire radial direction of the carcass, and that has a cord and a cord-coating layer containing a resin and coating the cord; and a tread provided outward in the tire radial direction of the belt layer.

Description

Run flat tires

The present disclosure relates to a run flat tire.

There is known a side-reinforcement type run-flat tire in which the tire side portion is reinforced with a side-reinforcing rubber to ensure durability during run-flat running (during abnormal running when air pressure decreases).
For example, Patent Document 1 proposes a run-flat tire in which an inner liner containing a non-diene rubber and a side reinforcing rubber layer containing a diene rubber contain the same kind of vulcanization accelerator.

On the other hand, as one attempt to improve the durability of the tire (for example, stress resistance, internal pressure resistance, and rigidity), a reinforcing cord member, which is a spirally wound metallic reinforcing cord, is provided on the outer periphery of the tire body. Has been. Further, in recent years, as a reinforcing cord member, one in which a resin-coated cord having a periphery of the reinforcing cord covered with a resin is wound is also used.
For example, in Patent Document 2, a tire formed of at least a thermoplastic resin material and having an annular tire skeleton is wound around the outer periphery of the tire skeleton in the circumferential direction to form a reinforcing cord layer. A tire having a reinforcing cord member and the reinforcing cord layer including a resin material has been proposed.

Patent Document 1: Patent 5629786 Patent Document 2: JP 2012-046025 A

Patent Document 2 describes a tire having a reinforcing cord member containing a resin material as described above. However, there is no description about the side-reinforcing rubber layer and the inner liner, and there is no description focusing on the adhesiveness between the two and the internal pressure retention by air permeation.
Here, the inner liner provided for the purpose of suppressing the air permeation of the pneumatic tire to maintain the internal pressure, and the side reinforcing rubber layer provided to reinforce the tire side portion that supports the load during run-flat traveling, A rubber material having a composition according to the purpose of is used.
Therefore, in a run flat tire in which the inner liner and the side reinforcing rubber layer are in direct contact with each other, the compositions of the two are different from each other, so that the adhesiveness at the interface is low and peeling may occur during run flat running. When the interface peels off, the location may affect the run-flat traveling property (that is, the durability during run-flat traveling).
On the other hand, Patent Document 1 describes a run-flat tire in which the side reinforcing rubber layer and the inner liner contain the same type of vulcanization accelerator to improve the adhesiveness between the two. However, as described above, a rubber material having a composition according to each purpose is used for the inner liner and the side-reinforcing rubber layer. Therefore, from this viewpoint, it is preferable that the vulcanization accelerator has a high degree of freedom in selection. ..
On the other hand, if the composition of the inner liner and the composition of the side reinforcing rubber layer are brought close to each other in order to enhance the adhesiveness of the interface, it becomes difficult to achieve the respective objects. Therefore, it is difficult to achieve both the tire internal pressure holding property and the run flat running property.

In consideration of the above facts, the present disclosure aims to provide a run-flat tire that has both the internal pressure holding property and the run-flat running property.

Specific means for solving the problems include the following embodiments.
<1> A pair of bead cores,
A carcass straddling the pair of bead cores, the end portion of which is locked to the bead core,
An inner liner provided on the tire inner surface side of the carcass, wherein the content of the diene rubber is 20% by mass or more based on the total amount of rubber contained in the inner liner,
A side reinforcing rubber layer provided in direct contact with the inner liner between the carcass of the tire side portion and the inner liner, and extending in the tire radial direction along the inner surface of the carcass,
A belt layer provided on the outer side in the tire radial direction of the carcass, having a cord and a cord coating layer that coats the cord and contains a resin,
A tread provided on the tire radial direction outer side of the belt layer,
Run-flat tire with.

According to the present disclosure, it is possible to provide a run-flat tire that has both the internal pressure holding property and the run-flat running property.

FIG. 3 is a half cross-sectional view showing one side of a cut surface obtained by cutting the run-flat tire according to the embodiment of the present disclosure along the tire width direction and the tire radial direction in a state of being assembled to a rim. It is a partial expanded sectional view showing a bead core in a run flat tire concerning one embodiment of this indication. 1 is a perspective view showing a belt layer in a run flat tire according to an embodiment of the present disclosure. FIG. 9 is a partially enlarged cross-sectional view showing a modified example in which a bead core is formed by a wire bundle in which a plurality of bead wires are coated with a coating resin in a run-flat tire according to an embodiment of the present disclosure. In a run-flat tire according to an embodiment of the present disclosure, a half cross-sectional view showing a modified example in which a plurality of reinforcing cords are coated with a coating resin and a belt layer is formed using a resin-coated cord having a substantially parallelogram shape in section. Is.

Hereinafter, specific embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments and is appropriately modified and implemented within the scope of the object of the present disclosure. be able to.
The size of the members in each drawing is conceptual, and the relative size relationship between the members is not limited to this. In addition, members having substantially the same function are denoted by the same reference numerals throughout the drawings, and redundant description may be omitted.

In the present specification, the "resin" is a concept including a thermoplastic resin, a thermoplastic elastomer, and a thermosetting resin, and does not include a vulcanized rubber. Further, in the following description of the resin, “same type” means a resin having a skeleton common to the skeleton constituting the resin main chain, such as ester-based resins and styrene-based resins.
In the present specification, a numerical range represented by “to” means a range including the numerical values before and after “to” as a lower limit value and an upper limit value.
In the present specification, the amount of each component in the composition is the sum of a plurality of substances present in the composition, unless a plurality of substances corresponding to each component are present in the composition. Means quantity.
In the present specification, the “main component” means a component having the largest content by mass in the mixture, unless otherwise specified.

Further, in the present specification, the term “thermoplastic resin” means a polymer compound in which the material softens and flows as the temperature rises and becomes relatively hard and strong when cooled, but does not have rubber-like elasticity.
The term "thermoplastic elastomer" as used herein means a copolymer having a hard segment and a soft segment. Specifically, as the thermoplastic elastomer, for example, a polymer that constitutes a crystalline hard segment having a high melting point or a hard segment having a high cohesive force, and a polymer that constitutes an amorphous and soft segment having a low glass transition temperature, The copolymer which has is mentioned. Further, examples of the thermoplastic elastomer include ones in which the material softens and flows as the temperature rises, becomes relatively hard and strong when cooled, and has rubber-like elasticity.
The hard segment refers to a component that is relatively harder than the soft segment. The hard segment is preferably a molecular constraining component that functions as a crosslinking point of the crosslinked rubber that prevents plastic deformation. As the hard segment, for example, a segment having a structure having a rigid group such as an aromatic group or an alicyclic group in the main skeleton, or a structure capable of intermolecular packing by intermolecular hydrogen bond or π-π interaction Is mentioned. Also, the soft segment refers to a component that is relatively softer than the hard segment. The soft segment is preferably a flexible component exhibiting rubber elasticity. Examples of the soft segment include a segment having a long-chain group (for example, a long-chain alkylene group) in the main chain, a high degree of freedom of molecular rotation, and a stretchable structure.

[Run flat tire]
FIG. 1 illustrates a cut surface (along a tire circumferential direction) cut along a tire width direction and a tire radial direction in an example of a run flat tire (hereinafter, referred to as “tire 10”) according to an embodiment of the present disclosure. Shows one side of the cross section as seen from the direction).
The arrow W in the figure indicates the width direction of the tire 10 (tire width direction), and the arrow R indicates the radial direction of the tire 10 (tire radial direction). The tire width direction mentioned here refers to a direction parallel to the rotation axis of the tire 10. Further, the tire radial direction means a direction orthogonal to the rotation axis of the tire 10. Reference numeral CL indicates the equatorial plane of the tire 10 (tire equatorial plane).

In the present embodiment, the side closer to the rotation axis of the tire 10 along the tire radial direction is “the tire radial direction inner side”, and the side farther from the rotation axis of the tire 10 along the tire radial direction is the “tire radial direction outer side”. Enter. On the other hand, the side closer to the tire equatorial plane CL along the tire width direction is referred to as "tire width direction inner side", and the side farther from the tire equatorial plane CL along the tire width direction is referred to as "tire width direction outer side".

FIG. 1 shows the tire 10 when assembled to a rim 30 which is a standard rim and filled with standard air pressure. The "standard rim" referred to here is the rim defined by JATMA (Japan Automobile Tire Manufacturer's Association) Year Book 2018 version. Further, the standard air pressure is the air pressure corresponding to the maximum load capacity of Year Book 2018 version of JATMA (Japan Automobile Tire Manufacturers Association).

As shown in FIG. 1, the tire 10 includes a pair of bead cores 26 embedded in the bead portion 12, a carcass 14 whose end portions straddle the bead core 26 are locked to the bead core 26, and a carcass 14 on the tire inner surface side. The inner liner 16 provided and between the carcass 14 of the tire side portion 22 and the inner liner 16 are provided in direct contact with the inner liner 16 and extend along the inner surface of the carcass 14 in the tire radial direction (i.e., side reinforcement rubber 24). A side reinforcing rubber layer), a belt layer 40 provided on the tire radial direction outer side of the tread portion 18 of the carcass 14, and a tread 20 provided on the tire radial direction outer side of the belt layer 40. In FIG. 1, only the bead portion 12 on one side is shown.

The inner liner 16 is made of a rubber material containing rubber, and the diene rubber is contained in an amount of 20% by mass or more based on the entire rubber (total amount of rubber) contained in the inner liner 16.
The belt layer 40 is configured to include a reinforcing cord 42C and a coating resin 42S (that is, a cord coating layer) that covers the reinforcing cord 42C and contains a resin. That is, the belt layer 40 contains resin. The details of the resin material forming the coating resin 42S will be described later.

Here, generally, the inner liner is a layer provided to enhance the internal pressure retention of the tire, and is preferably a layer having low air permeability, and therefore a rubber other than the diene rubber (that is, a non-diene rubber) is used. Often composed of a rubber material including (rubber). On the other hand, the side-reinforcing rubber is a layer for reinforcing the tire side portion that generally bears the load acting on the tire during run-flat running, and it is desirable that the side-reinforcing rubber has a hardness high enough to enable reinforcement. Therefore, the inner liner is composed of a rubber material having a different composition. Therefore, even if vulcanization is performed in a state where the unvulcanized inner liner and the unvulcanized side reinforcing rubber are in contact with each other, the adhesive force at the interface hardly increases.
In addition, in order to increase the adhesive strength at the interface, for example, if the composition of the rubber material used for the inner liner is brought close to the composition of the rubber material used for the side reinforcing rubber, the adhesive strength at the interface increases, but the air permeability of the inner liner increases. May increase, and the internal pressure retention may decrease.

On the other hand, in the tire 10, the inner liner 16 that is in direct contact with the side reinforcing rubber 24 contains 20 mass% or more of diene rubber with respect to the entire rubber (total amount of rubber), and the belt layer 40 contains resin. .. As a result, both the internal pressure holding property and the run flat traveling property are compatible. The reason is not clear, but it is presumed as follows.

In the process of manufacturing the side reinforcing rubber 24, vulcanization is performed at a relatively high vulcanization speed in order to form a layer having a hardness that is high enough to reinforce the tire side portion 22. When the inner liner 16 contains 20% by mass or more of the diene rubber, the vulcanization speed is higher in the process of manufacturing the inner liner 16 as compared with the case where the diene rubber is not included, and the vulcanization speeds of both approaches. it is conceivable that. Therefore, if vulcanization is performed with the unvulcanized inner liner and the unvulcanized side reinforcing rubber in contact with each other, they will be vulcanized at a similar speed, which facilitates co-crosslinking and the adhesive strength of the interface. Is estimated to be high.
In particular, when the side reinforcing rubber 24 contains a diene rubber, the inner liner 16 also contains 20% by mass or more of the diene rubber, so that further co-crosslinking occurs as compared with the case where the inner liner 16 does not contain the diene rubber. It is presumed that it will be easier and the adhesive strength at the interface will be higher.
In this way, the adhesive force between the inner liner 16 and the side reinforcing rubber 24 is increased, so that peeling of the interface hardly occurs and the run-flat traveling property is improved.

In addition, since the belt layer 40 contains the resin, the inner pressure retaining property of the entire tire 10 is easily maintained. That is, the resin is used for the belt layer provided in the tread portion, which is a region in the tire where the internal pressure retention is likely to be deteriorated due to the permeation of air. Resins generally have lower air permeability than rubbers. Therefore, even if the inner liner contains a diene rubber and the air barrier property of the inner liner itself is lowered, the air permeability in the tread portion can be kept low, and the inner pressure holding property of the tire as a whole is maintained. ..
As described above, in the tire 10, it is presumed that the internal pressure holding property and the run flat running property are compatible with each other.
Hereinafter, each part of the tire 10 will be described.

<Bead part>
A bead core 26 including a wire bundle is embedded in each of the pair of bead portions 12. The carcass 14 straddles these bead cores 26. The bead core 26 can adopt various structures in a pneumatic tire, such as a circular cross section and a polygonal shape, and can adopt, for example, a hexagon as the polygon, but in the present embodiment, it is a quadrangle. There is.

As shown in FIG. 2, the bead core 26 includes, for example, a bead wire 26A and a coating resin 26B that covers the bead wire 26A and contains a resin (that is, a bead coating layer). The bead core 26 is formed by winding a single bead wire 26A coated with the coating resin 26B a plurality of times and laminating it. Specifically, the bead wire 26A coated with the coating resin 26B is wound in the tire width direction without gaps to form a first row, and thereafter, the rows are stacked on the tire radial direction outside with no gaps, and the cross-sectional shape is quadrangular. To form the bead core 26. At this time, the coating resins 26B of the bead wires 26A that are adjacent to each other in the tire width direction and the radial direction are joined to each other. Thereby, the bead core 26 in which the bead wire 26A is coated with the coating resin 26B is formed.

In the tire 10 shown in FIGS. 1 and 2, not only the belt layer 40 but also the bead core 26 contains a resin, so that the internal pressure retention of the tire 10 is more likely to be maintained, and the internal pressure retention and the run flat traveling property are more compatible. To be done. The resin material forming the coating resin 26B is the same as the resin material forming the coating resin 42S described later.

In the present embodiment, the bead core 26 is formed by winding one bead wire 26A coated with the coating resin 26B and laminating the bead wire 26A, but the embodiment of the present disclosure is not limited to this. For example, like a bead core 60 shown in FIG. 4, a wire bundle in which a plurality of bead wires 60A are coated with a coating resin 60B may be wound and laminated.

In this case, the interface during lamination is fused by heat welding. The number of bead wires 60A included in one wire bundle is not limited to three, and may be two or four or more. Further, the number of wire bundles in each layer for stacking the wire bundles may be one as shown in FIG. 4, or may be two or more bundles adjacent to each other in the tire width direction.

In the present embodiment, the bead wire 26A is coated with the coating resin 26B to form the bead core 26, but the embodiment of the present disclosure is not limited to this. For example, instead of the coating resin 26B, a coating rubber containing rubber may be used.

As shown in FIG. 1, the tire 10 further includes a bead filler 28 embedded in the bead portion 12 and extending from the bead core 26 to the tire radial direction outer side along the outer surface of the carcass 14. The bead filler 28 contains a resin and is embedded in a region of the bead portion 12 surrounded by the carcass 14 (a region outside the portion of the carcass 14 that is arranged inside the tire width direction around the bead core 26). Further, the bead filler 28 has a thickness that decreases toward the end portion 28A on the outer side in the tire radial direction.

In the tire 10 shown in FIG. 1 and FIG. 2, not only the belt layer 40 but also the bead filler 28 contains a resin, so that the internal pressure retention of the tire 10 is more easily maintained, and the internal pressure retention and the run flat traveling property are improved. More compatible. The resin material forming the bead filler 28 is the same as the resin material forming the coating resin 42S described later.

In the present embodiment, the bead filler 28 containing a resin is used, but the embodiment of the present disclosure is not limited to this, and includes, for example, rubber (preferably containing rubber as a main component (for example, for the whole bead filler). Bead filler may be used.

<Carcass>
The carcass 14 is a tire frame member including two carcass plies 14A and 14B. The carcass ply 14A is a carcass ply arranged on the tire equatorial plane CL on the outer side in the tire radial direction, and the carcass ply 14B is a carcass ply arranged on the inner side in the tire radial direction. Each of the carcass plies 14A and 14B is configured to include a plurality of cords and a coated rubber that coats the cords and contains rubber.
The coated rubber is not particularly limited, and examples thereof include a rubber material containing a diene rubber (for example, natural rubber). In particular, when the coating rubber contains a diene-based rubber and the carcass 14 and the inner liner 16 are in direct contact with each other, the inner liner 16 contains 20% by mass or more of the diene-based rubber, whereby the inner liner 16 and the carcass 14 are The adhesiveness with is also high. Therefore, run-flat traveling performance is further improved.

The carcass 14 thus formed extends in a toroidal shape from one bead core 26 to the other bead core 26 to form a tire skeleton. The end portion side of the carcass 14 is locked to the bead core 26. Specifically, the end portion side of the carcass 14 is folded back around the bead core 26 from the tire width direction inner side to the tire width direction outer side and locked. Further, the folded back end portions (end portions 14AE and 14BE) of the carcass 14 are arranged on the tire side portion 22. The end portion 14AE of the carcass ply 14A is arranged inside the end portion 14BE of the carcass ply 14B in the tire radial direction.

In the present embodiment, the end portion of the carcass 14 is arranged on the tire side portion 22, but the present disclosure is not limited to this structure. For example, the end portion of the carcass 14 is arranged on the belt layer 40. Good. Alternatively, the end portion side of the carcass 14 may be sandwiched between a plurality of bead cores 26 or may be wound around the bead cores 26 without being folded back. In this specification, "locking" the end of the carcass 14 to the bead core 26 includes various embodiments such as these.

Note that, in the present embodiment, the carcass 14 is a radial carcass. The material of the cord included in the carcass 14 is not particularly limited, and rayon, nylon, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), aramid, glass fiber, carbon fiber, steel or the like can be used. From the viewpoint of weight reduction, the organic fiber cord is preferable. Further, the number of driving the carcass is set in the range of 20 to 60 pieces / 50 mm, but the number is not limited to this range.

<Belt layer>
A belt layer 40 is disposed on the outer side of the carcass 14 in the tire radial direction. As shown in FIG. 3, the belt layer 40 is a ring-shaped batter formed by spirally winding the resin-coated cord 42 around the outer peripheral surface of the carcass 14 along the tire circumferential direction.

The resin-coated cord 42 is formed by coating the reinforcing cord 42C with the coating resin 42S, and has a substantially square cross section as shown in FIG. The coating resin 42S on the inner peripheral portion of the resin coated cord 42 in the tire radial direction is configured to be bonded to the outer peripheral surface of the carcass 14 via rubber and, if necessary, an adhesive. Further, the coating resins 42S that are adjacent to each other in the tire width direction of the resin coating cord 42 are integrally joined by heat welding or an adhesive. As a result, the belt layer 40 (resin-coated belt layer) including the reinforcing cord 42C coated with the coating resin 42S is formed.

In the present embodiment, the resin coated cord 42 is configured by coating one reinforcing cord 42C with the coating resin 42S, but may be configured by coating a plurality of reinforcing cords 42C with the coating resin 42S. Good.

Further, the bead wire 26A in the bead core 26 and the reinforcing cord 42C in the belt layer 40 of the present embodiment are steel cords. This steel cord is mainly composed of steel and can contain various trace contents such as carbon, manganese, silicon, phosphorus, sulfur, copper and chromium.

Note that the embodiment of the present disclosure is not limited to this, and as at least one selected from the group consisting of the bead wire 26A and the reinforcing cord 42C, a monofilament cord, a cord obtained by twisting a plurality of filaments, or the like is used instead of the steel cord. May be used. Various designs can be adopted for the twist structure, and various cross-sectional structures, twist pitches, twist directions, and distances between adjacent filaments can be used. Further, a cord obtained by twisting filaments made of different materials can be adopted, and the cross-sectional structure is not particularly limited, and various twist structures such as single twist, layer twist, and multiple twist can be adopted. A resin cord (that is, a cord containing a resin) may be used as at least one selected from the group consisting of the bead wire 26A and the reinforcing cord 42C.

Further, in the present embodiment, the belt layer 40 is formed by winding the substantially square resin-coated cord 42 formed by coating one reinforcing cord 42C with the coating resin 42S around the outer peripheral surface of the carcass 14. The embodiment of the present disclosure is not limited to this.
For example, as in the belt layer 70 shown in FIG. 5, a resin-coated cord 72 having a substantially parallelogram-shaped cross section, which is formed by coating a plurality of reinforcing cords 72C with a coating resin 72S, is wound around the outer peripheral surface of the carcass 14. You may form it.

<Tread>
A tread 20 is provided outside the belt layer 40 in the tire radial direction in the tread portion 18. The tread 20 is a portion that comes into contact with the road surface during traveling, and a plurality of circumferential grooves 50 extending in the tire circumferential direction are formed on the tread surface of the tread 20. The shape and the number of the circumferential grooves 50 are appropriately set according to performances such as drainage and steering stability required for the tire 10.

<Inner liner>
The inner liner 16 is provided as a continuous layer on the tire inner surface side of the carcass 14 (that is, the tire width direction inner side of the bead portion 12, the tire width direction inner side of the tire side portion 22, and the tread portion 18 tire radial direction inner side). ing. The inner liner 16 is a layer provided to increase the internal pressure retention of the tire 10 by reducing the air permeability.
The inner liner 16 is provided in direct contact with at least the inner peripheral surface of the side reinforcing rubber 24 (that is, the inner surface in the tire width direction). On the other hand, in the tire 10, the inner liner 16 is also provided in direct contact with the inner peripheral surface (that is, the inner surface in the tire radial direction) of the tread portion 18 of the carcass 14. However, the present invention is not limited to this, and the carcass 14 and the inner It may have another layer between it and the liner 16.

Further, in the tire 10, the inner liner 16 is provided as a continuous layer from one bead portion 12 to the other bead portion 12. The inner liner 16 is not limited to this as long as it is provided in contact with at least a part of the side reinforcing rubber 24 in a region where it is desirable to block air, but from the viewpoint of the internal pressure retaining property, the tire of the tire 10 is not limited thereto. It is preferably provided on the entire inner surface.
The thickness of the inner liner 16 is, for example, in the range of 0.1 mm or more and 0.4 mm or less. The inner liner 16 may have the same thickness from the one bead portion 12 to the other bead portion 12, and in particular, the region where it is desired to reduce the air permeability may be relatively thick.

The inner liner 16 contains at least a diene rubber. The content ratio of the diene rubber to the entire rubber (total amount of rubber) contained in the inner liner 16 is 20% by mass or more, and from the viewpoint of adhesiveness with the side reinforcing rubber 24, 35% by mass or more is preferable, and 50% by mass. % Or more is more preferable.
When the inner liner 16 contains the diene rubber in the above range, the adhesion between the inner liner and the side reinforcing rubber 24 becomes high. In addition, when the inner liner 16 is in contact with the carcass 14, the adhesion between the inner liner 16 and the carcass 14 is also high.

Here, the diene rubber refers to a rubber containing a double bond in the main chain of the rubber (specifically, containing 2.5 mol% or more). Examples of the diene rubber include natural rubber (NR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), and polychloroprene rubber (CR). ) And other synthetic rubbers. The diene rubbers may be used alone or as a mixture of two or more.
Among these, natural rubber (NR) is preferable as the diene rubber from the viewpoint of adhesiveness with the side reinforcing rubber 24.

The inner liner 16 preferably contains a non-diene rubber in addition to the diene rubber from the viewpoint of lowering air permeability. The content of the non-diene rubber with respect to the entire rubber (total amount of rubber) contained in the inner liner 16 is preferably 20% by mass or more, more preferably 30% by mass or more, and 40% by mass from the viewpoint of reducing air permeability. The above is more preferable. That is, the content ratio of the diene rubber to the entire rubber (total amount of rubber) contained in the inner liner 16 is preferably 80% by mass or less, more preferably 70% by mass or less, from the viewpoint of reducing air permeability. It is more preferably not more than mass%.

Here, the non-diene rubber refers to a rubber that contains almost no double bonds in the main chain of the rubber (specifically, less than 2.5 mol%). Examples of the non-diene rubber include butyl rubber (butyl rubber (IIR), halogenated butyl rubber, etc.), ethylene / propylene rubber (EPM, EPDM), urethane rubber (U), silicone rubber (Q), chlorosulfonated rubber. (CSM), acrylic rubber (ACM), fluororubber (FKM), chlorosulfonated polyethylene and the like.
As the non-diene rubber, butyl rubber is preferable among them from the viewpoint of reducing air permeability, and among them, butyl rubber (IIR) and bromobutyl rubber are more preferable.

The rubber material forming the inner liner 16 may include other components other than rubber, if necessary, in addition to rubber.
Other components include, for example, reinforcing materials such as carbon black, fillers (fillers, short fibers, resins, etc.), vulcanizing agents, vulcanization accelerators, fatty acids or salts thereof, metal oxides, process oils, anti-aging agents. Agents and the like.
As the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxides, resin vulcanizing agents and the like are used. Among them, it is preferable that sulfur is used as the vulcanizing agent.
As the vulcanization accelerator, known vulcanization accelerators such as aldehydes, ammonias, amines, guanidines, thioureas, thiazoles, sulfenamides, thiurams, dithiocarbamates, xanthates and the like are used. Be done.
Examples of the fatty acid include stearic acid, palmitic acid, myristic acid, and lauric acid, and these may be blended in a salt state such as zinc stearate. Of these, stearic acid is preferred.
Examples of the metal oxide include zinc white (ZnO), iron oxide, magnesium oxide, and the like, and zinc white is preferable.
The process oil may be any of aromatic type, naphthene type and paraffin type. As the antiaging agent, amine-ketone type, imidazole type, amine type, phenol type, sulfur type, phosphorus type and the like can be mentioned.

<Side reinforcement rubber>
The tire side portion 22 is configured to extend in the tire radial direction, connect the bead portion 12 and the tread portion 18, and can bear the load acting on the tire 10 during run flat traveling. In the tire side portion 22, a side reinforcing rubber 24 that reinforces the tire side portion 22 is provided inside the carcass 14 in the tire width direction. Specifically, the side reinforcing rubber 24 is provided between the carcass 14 and the inner liner 16 and at least in direct contact with the inner liner 16. The side reinforcing rubber 24 is a reinforcing rubber for traveling a predetermined distance while supporting the weight of the vehicle and an occupant when the internal pressure of the tire 10 decreases due to puncture or the like.

The side reinforcing rubber 24 extends in the tire radial direction from the bead portion 12 side to the tread 20 side along the inner surface of the carcass 14. Further, the side reinforcing rubber 24 has a shape in which the thickness decreases from the central portion toward the bead portion 12 side and the tread 20 side, for example, a substantially crescent shape. The thickness of the side reinforcing rubber 24 referred to here means the length along the normal line of the carcass 14.

The lower end portion 24B of the side reinforcing rubber 24 on the bead portion 12 side overlaps the bead filler 28 with the carcass 14 in between when viewed in the tire width direction. Further, the upper end portion 24A of the side reinforcing rubber 24 on the tread 20 side overlaps with the belt layer 40 when viewed in the tire radial direction. Specifically, the upper end portion 24A of the side reinforcing rubber 24 overlaps the belt layer 40 with the carcass 14 interposed therebetween. In other words, the upper end portion 24A of the side reinforcing rubber 24 is located inside the tire width direction end portion 40E of the belt layer 40 in the tire width direction.

In the present embodiment, the side reinforcing rubber 24 is formed of one type of rubber material, but the embodiment of the present disclosure is not limited to this, and may be formed of a plurality of rubber materials.
The side-reinforcing rubber 24 preferably contains rubber as a main component, and from the viewpoint of run-flat running property, it is preferable that the side-reinforcing rubber 24 include a diene rubber, and more preferably, a butadiene rubber (BR). It is also preferable to contain butadiene rubber (BR) and natural rubber (NR).
The content of the diene rubber with respect to the entire rubber (total amount of rubber) contained in the side reinforcing rubber 24 is preferably 70% by mass or more, and more preferably 90% by mass or more, from the viewpoint of run-flat traveling property.

The rubber material forming the side reinforcing rubber 24 may include, in addition to rubber, other components other than rubber, if necessary. Examples of the other components include the same components as the other components that may be included in the rubber material forming the inner liner 16 if necessary.
Among them, the rubber material forming the side reinforcing rubber 24 preferably contains a thiuram accelerator as a vulcanization accelerator in order to enhance durability during run-flat running.

The hardness of the side reinforcing rubber 24 is preferably 70 or more and 85 or less from the viewpoint of run-flat traveling property. The hardness of the side reinforcing rubber 24 refers to the hardness defined by JIS K6253 (type A durometer).
Further, the loss coefficient tan δ of the side reinforcing rubber 24 at a temperature of 60 ° C. and a frequency of 20 Hz is preferably 0.10 or less. The loss coefficient tan δ is a value measured using a viscoelastic spectrometer (a spectrometer manufactured by Toyo Seiki Seisaku-sho, Ltd.) under the conditions of a frequency of 20 Hz, an initial strain of 10%, a dynamic strain of ± 2%, and a temperature of 60 ° C.

<Resin material>
Hereinafter, the resin material used for the coating resin 42S in the belt layer 40 will be described. The resin material used for the coating resin 26B and the bead filler 28 in the bead core 26 is the same as the resin material used for the coating resin 42S in the belt layer 40.
The resin material contains at least a resin and may contain other components as necessary.
The resin material preferably contains a resin as a main component. Specifically, the resin content with respect to the total amount of the resin material is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 75% by mass or more.
The resin material may contain any of a thermoplastic resin, a thermoplastic elastomer, and a thermosetting resin as the resin, but preferably contains at least one selected from the group consisting of a thermoplastic resin and a thermoplastic elastomer, More preferably, it contains a thermoplastic elastomer.

Examples of the thermoplastic resin include polyester-based thermoplastic resin, polyamide-based thermoplastic resin, polystyrene-based thermoplastic resin, polyurethane-based thermoplastic resin, polyolefin-based thermoplastic resin, vinyl chloride-based thermoplastic resin, and the like.

Examples of the thermoplastic elastomer include polyester thermoplastic elastomer (TPC), polyamide thermoplastic elastomer (TPA), polystyrene thermoplastic elastomer (TPS), polyurethane thermoplastic elastomer (TPU), which are defined in JIS K6418. Examples thereof include a polyolefin-based thermoplastic elastomer (TPO), a crosslinked thermoplastic rubber (TPV), or another thermoplastic elastomer (TPZ).

Examples of the thermosetting resin include phenol-based thermosetting resin, urea-based thermosetting resin, melamine-based thermosetting resin, and epoxy-based thermosetting resin.

The resin material may contain one of these resins alone, or may contain two or more kinds of resins in combination.
Among these, as the resin, polyester-based thermoplastic elastomer, polyester-based thermoplastic resin, polyamide-based thermoplastic elastomer, polyamide-based thermoplastic resin, polystyrene-based thermoplastic elastomer, polystyrene-based thermoplastic resin, polyurethane-based thermoplastic elastomer, A polyurethane-based thermoplastic resin, a polyolefin-based thermoplastic elastomer, or a polyolefin-based thermoplastic resin is preferable.
The resin material preferably contains at least one selected from the group consisting of a polyester-based thermoplastic elastomer, a polyester-based thermoplastic resin, a polyamide-based thermoplastic elastomer, and a polyamide-based thermoplastic resin. The polyester-based thermoplastic elastomer and the polyester It is more preferable to include at least one selected from the group consisting of thermoplastic resins.

-Thermoplastic elastomer-
(Polyester thermoplastic elastomer)
As the polyester-based thermoplastic elastomer, for example, at least polyester forms a hard segment having a high melting point and another polymer (for example, polyester or polyether) is a soft segment having a low glass transition temperature and being amorphous. The forming material is mentioned.

As the polyester forming the hard segment, an aromatic polyester can be used. The aromatic polyester can be formed from, for example, an aromatic dicarboxylic acid or its ester-forming derivative and an aliphatic diol. The aromatic polyester is preferably polybutylene terephthalate derived from at least one selected from the group consisting of terephthalic acid and dimethyl terephthalate, and 1,4-butanediol. The aromatic polyesters include, for example, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5 A dicarboxylic acid component such as sulfoisophthalic acid or an ester-forming derivative thereof, and a diol having a molecular weight of 300 or less (eg, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, etc. Aliphatic diols; alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethylol; xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxyphenyl) propane, 2,2- B Sus [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane, 4,4'- Aromatic diols such as dihydroxy-p-terphenyl and 4,4′-dihydroxy-p-quarterphenyl; etc.) and polyesters derived from these, or a combination of two or more of these dicarboxylic acid components and diol components It may be polymerized polyester. It is also possible to copolymerize a trifunctional or higher polyfunctional carboxylic acid component, a polyfunctional oxyacid component, a polyfunctional hydroxy component, etc. within a range of 5 mol% or less.
Examples of the polyester forming the hard segment include polyethylene terephthalate, polybutylene terephthalate, polymethylene terephthalate, polyethylene naphthalate and polybutylene naphthalate, and polybutylene terephthalate is preferable.

Examples of the polymer that forms the soft segment include aliphatic polyester and aliphatic polyether.
Examples of the aliphatic polyether include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, and poly (propylene oxide). ) An ethylene oxide addition polymer of glycol, a copolymer of ethylene oxide and tetrahydrofuran and the like can be mentioned.
Examples of the aliphatic polyester include poly (ε-caprolactone), polyenanthlactone, polycaprylolactone, polybutylene adipate, polyethylene adipate and the like.
Among these aliphatic polyethers and aliphatic polyesters, as the polymer forming the soft segment, poly (tetramethylene oxide) glycol and poly (propylene oxide) glycol are used from the viewpoint of the elastic properties of the obtained polyester block copolymer. Ethylene oxide adduct, poly (ε-caprolactone), polybutylene adipate, polyethylene adipate and the like are preferable.

The number average molecular weight of the polymer forming the soft segment is preferably 300 to 6000 from the viewpoint of toughness and low temperature flexibility. Further, the mass ratio (x: y) of the hard segment (x) and the soft segment (y) is preferably 99: 1 to 20:80, and more preferably 98: 2 to 30:70 from the viewpoint of moldability. ..

As a combination of the above-mentioned hard segment and soft segment, for example, each combination of the above-mentioned hard segment and soft segment can be mentioned. Among these, as the combination of the hard segment and the soft segment described above, the hard segment is polybutylene terephthalate, preferably a combination in which the soft segment is an aliphatic polyether, the hard segment is polybutylene terephthalate, the soft segment More preferred is the combination where is a poly (ethylene oxide) glycol.

Examples of commercially available polyester thermoplastic elastomers include "Hytrel" series (for example, 3046, 5557, 6347, 4047N, 4767N) manufactured by Toray-Dupont Co., Ltd., "Perprene" series manufactured by Toyobo Co., Ltd. (For example, P30B, P40B, P40H, P55B, P70B, P150B, P280B, E450B, P150M, S1001, S2001, S5001, S6001, S9001, etc.) can be used.

The polyester-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.

(Polyamide thermoplastic elastomer)
The polyamide-based thermoplastic elastomer is a thermoplastic resin material composed of a copolymer having a polymer that forms a crystalline and hard segment with a high melting point and an amorphous polymer that forms a soft segment with a low glass transition temperature. It means that the main chain of the polymer forming the hard segment has an amide bond (—CONH—).
As the thermoplastic polyamide-based elastomer, for example, at least polyamide is a crystalline soft segment having a high melting point, and another polymer (for example, polyester, polyether, etc.) is a soft segment having a low glass transition temperature and being amorphous. The forming material is mentioned. In addition to the hard segment and the soft segment, the polyamide-based thermoplastic elastomer may be formed using a chain extender such as dicarboxylic acid.
Specific examples of the polyamide-based thermoplastic elastomer include the amide-based thermoplastic elastomer (TPA) defined in JIS K6418: 2007, and the polyamide-based elastomer described in JP 2004-346273 A. it can.

In the polyamide-based thermoplastic elastomer, examples of the polyamide that forms the hard segment include a polyamide formed by a monomer represented by the following general formula (1) or (2).

 

In the general formula (1), R ¹ represents a hydrocarbon molecular chain having 2 to 20 carbon atoms (for example, an alkylene group having 2 to 20 carbon atoms).

 

In the general formula (2), R ² represents a hydrocarbon molecular chain having 3 to 20 carbon atoms (for example, an alkylene group having 3 to 20 carbon atoms).

In the general formula (1), R ¹ is preferably a hydrocarbon molecular chain having 3 to 18 carbon atoms, for example, an alkylene group having 3 to 18 carbon atoms, and a molecular chain of hydrocarbon having 4 to 15 carbon atoms, for example, carbon An alkylene group having 4 to 15 carbon atoms is more preferable, and a hydrocarbon molecular chain having 10 to 15 carbon atoms, for example, an alkylene group having 10 to 15 carbon atoms is particularly preferable.
Further, in the general formula (2), as R ² , a hydrocarbon molecular chain having 3 to 18 carbon atoms, for example, an alkylene group having 3 to 18 carbon atoms is preferable, and a molecular chain of hydrocarbon having 4 to 15 carbon atoms, For example, an alkylene group having 4 to 15 carbon atoms is more preferable, and a hydrocarbon molecular chain having 10 to 15 carbon atoms, for example, an alkylene group having 10 to 15 carbon atoms is particularly preferable.
Examples of the monomer represented by the general formula (1) or the general formula (2) include ω-aminocarboxylic acid and lactam. Examples of polyamides that form the hard segment include polycondensates of these ω-aminocarboxylic acids or lactams, and copolycondensates of diamines and dicarboxylic acids.

Examples of ω-aminocarboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 10-aminocapric acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like having 5 to 20 carbon atoms. Examples thereof include aliphatic ω-aminocarboxylic acid. Examples of lactams include aliphatic lactams having 5 to 20 carbon atoms such as lauryl lactam, ε-caprolactam, udecane lactam, ω-enanthlactam and 2-pyrrolidone.
Examples of diamines include aliphatic diamines having 2 to 20 carbon atoms and aromatic diamines having 6 to 20 carbon atoms. Examples of the aliphatic diamine having 2 to 20 carbon atoms and the aromatic diamine having 6 to 20 carbon atoms include, for example, ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, Examples include decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 3-methylpentamethylenediamine, and metaxylenediamine. it can.
Further, the dicarboxylic acid can be represented by HOOC- (R ³ ) _m —COOH (R ³ : a molecular chain of a hydrocarbon having 3 to 20 carbon atoms, m: 0 or 1), and examples thereof include oxalic acid and succinic acid. And aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as glutamic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid.
As the polyamide forming the hard segment, a polyamide obtained by ring-opening polycondensation of lauryl lactam, ε-caprolactam, or udecanlactam can be preferably used.

Examples of the polymer that forms the soft segment include polyester and polyether. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and ABA type triblock polyether. These may be used alone or in combination of two or more. Further, polyether diamine or the like obtained by reacting the end of polyether with ammonia or the like can also be used.
Here, the "ABA type triblock polyether" means a polyether represented by the following general formula (3).

 

In the general formula (3), x and z represent an integer of 1 to 20. y represents an integer of 4 to 50.

In the general formula (3), each of x and z is preferably an integer of 1 to 18, more preferably an integer of 1 to 16, even more preferably an integer of 1 to 14, and particularly preferably an integer of 1 to 12. Further, in the general formula (3), y is preferably an integer of 5 to 45, more preferably an integer of 6 to 40, further preferably an integer of 7 to 35, particularly preferably an integer of 8 to 30.

As the combination of the hard segment and the soft segment, each combination of the hard segment and the soft segment mentioned above can be mentioned. Among these, as the combination of the hard segment and the soft segment, the combination of lauryl lactam ring-opening polycondensate / polyethylene glycol, the combination of lauryl lactam ring-opening polycondensate / polypropylene glycol, the lauryl lactam ring-opening polycondensation Body / polytetramethylene ether glycol combination, or a combination of lauryl lactam ring-opening polycondensate / ABA type triblock polyether, and a combination of lauryl lactam ring-opening polycondensate / ABA type triblock polyether is more preferable. preferable.

The number average molecular weight of the polymer (polyamide) forming the hard segment is preferably 300 to 15,000 from the viewpoint of melt moldability. The number average molecular weight of the polymer forming the soft segment is preferably 200 to 6000 from the viewpoint of toughness and low temperature flexibility. Further, the mass ratio (x: y) of the hard segment (x) and the soft segment (y) is preferably 50:50 to 90:10, and more preferably 50:50 to 80:20 from the viewpoint of moldability. ..

The thermoplastic polyamide-based elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.

Commercially available polyamide-based thermoplastic elastomers include, for example, UBE Industries' UBESTA XPA series (eg, XPA9068X1, XPA9063X1, XPA9055X1, XPA9048X2, XPA9048X1, XPA9040X1, XPA9040X2XPA9044, etc.), Daicel Eponic Co., Ltd. “Vestamide” series (eg, E40-S3, E47-S1, E47-S3, E55-S1, E55-S3, EX9200, E50-R2, etc.) can be used.

(Polystyrene thermoplastic elastomer)
As the thermoplastic polystyrene-based elastomer, for example, at least polystyrene forms a hard segment, and other polymers (for example, polybutadiene, polyisoprene, polyethylene, hydrogenated polybutadiene, hydrogenated polyisoprene) are amorphous and have a glass transition temperature. A material forming a low soft segment is included. As the polystyrene forming the hard segment, for example, those obtained by a known radical polymerization method, ionic polymerization method or the like are preferably used, and specifically, polystyrene having anion living polymerization is mentioned. Examples of the polymer forming the soft segment include polybutadiene, polyisoprene, poly (2,3-dimethyl-butadiene) and the like.

As the combination of the hard segment and the soft segment, each combination of the hard segment and the soft segment mentioned above can be mentioned. Among these, the combination of the hard segment and the soft segment is preferably the combination of polystyrene / polybutadiene or the combination of polystyrene / polyisoprene. Further, the soft segment is preferably hydrogenated in order to suppress an unintended crosslinking reaction of the thermoplastic elastomer.

The number average molecular weight of the polymer (polystyrene) forming the hard segment is preferably 5,000 to 500,000, more preferably 10,000 to 200,000.
The number average molecular weight of the polymer forming the soft segment is preferably 5,000 to 1,000,000, more preferably 10,000 to 800,000, and further preferably 30,000 to 500,000. Further, the volume ratio (x: y) of the hard segment (x) and the soft segment (y) is preferably 5:95 to 80:20 and more preferably 10:90 to 70:30 from the viewpoint of moldability. ..

The thermoplastic polystyrene-based elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.
Examples of the polystyrene-based thermoplastic elastomer include styrene-butadiene-based copolymers [SBS (polystyrene-poly (butylene) block-polystyrene), SEBS (polystyrene-poly (ethylene / butylene) block-polystyrene)], styrene-isoprene. Copolymer (polystyrene-polyisoprene block-polystyrene), styrene-propylene copolymer [SEP (polystyrene- (ethylene / propylene) block), SEPS (polystyrene-poly (ethylene / propylene) block-polystyrene), SEEPS ( Polystyrene-poly (ethylene-ethylene / propylene) block-polystyrene), SEB (polystyrene (ethylene / butylene) block)] and the like.

Examples of commercially available polystyrene-based thermoplastic elastomers include, for example, "Tuftec" series manufactured by Asahi Kasei (for example, H1031, H1041, H1043, H1051, H1052, H1053, H1062, H1082, H1141, H1221, H1272, etc.), "SEBS" series (8007, 8076, etc.) and "SEPS" series (2002, 2063, etc.) manufactured by Kuraray Co., Ltd. can be used.

(Polyurethane thermoplastic elastomer)
As the thermoplastic polyurethane-based elastomer, for example, at least polyurethane forms a hard segment in which pseudo-crosslinking is formed by physical agglomeration, and another polymer forms an amorphous soft segment having a low glass transition temperature. Ingredients are listed.
Specific examples of the polyurethane-based thermoplastic elastomer include a polyurethane-based thermoplastic elastomer (TPU) defined in JIS K6418: 2007. The polyurethane-based thermoplastic elastomer can be represented as a copolymer including a soft segment including a unit structure represented by the following formula A and a hard segment including a unit structure represented by the following formula B.

 

In the formula, P represents a long-chain aliphatic polyether or a long-chain aliphatic polyester. R represents an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon. P'represents a short chain aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon.

As the long-chain aliphatic polyether or the long-chain aliphatic polyester represented by P in the formula A, for example, those having a molecular weight of 500 to 5000 can be used. P is derived from a diol compound containing a long-chain aliphatic polyether represented by P and a long-chain aliphatic polyester. Examples of such a diol compound include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, poly (butylene adipate) diol, poly-ε-caprolactone diol, poly (hexamethylene carbonate) having a molecular weight within the above range. Examples thereof include diols and ABA type triblock polyethers.
These may be used alone or in combination of two or more.

In Formula A and Formula B, R is a partial structure introduced using a diisocyanate compound containing an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon represented by R. Examples of the aliphatic diisocyanate compound containing an aliphatic hydrocarbon represented by R include 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butane diisocyanate and 1,6-hexamethylene diisocyanate. Can be mentioned.
Examples of the diisocyanate compound containing an alicyclic hydrocarbon represented by R include 1,4-cyclohexane diisocyanate and 4,4-cyclohexane diisocyanate. Further, examples of the aromatic diisocyanate compound containing an aromatic hydrocarbon represented by R include 4,4′-diphenylmethane diisocyanate and tolylene diisocyanate.
These may be used alone or in combination of two or more.

As the short-chain aliphatic hydrocarbon, alicyclic hydrocarbon or aromatic hydrocarbon represented by P ′ in the formula B, for example, those having a molecular weight of less than 500 can be used. P'is derived from a diol compound containing a short chain aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon represented by P '. Examples of the aliphatic diol compound containing a short chain aliphatic hydrocarbon represented by P ′ include glycol and polyalkylene glycol, and specifically, ethylene glycol, propylene glycol, trimethylene glycol, 1,4 -Butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10- Decanediol and the like can be mentioned.
Examples of the alicyclic diol compound containing an alicyclic hydrocarbon represented by P ′ include cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, Examples thereof include cyclohexane-1,4-diol and cyclohexane-1,4-dimethanol.
Furthermore, examples of the aromatic diol compound containing an aromatic hydrocarbon represented by P ′ include hydroquinone, resorcin, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4′- Dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1, Examples thereof include 1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-hydroxyphenoxy) ethane, 1,4-dihydroxynaphthalene and 2,6-dihydroxynaphthalene.
These may be used alone or in combination of two or more.

The number average molecular weight of the polymer (polyurethane) forming the hard segment is preferably 300 to 1500 from the viewpoint of melt moldability. The number average molecular weight of the polymer forming the soft segment is preferably 500 to 20,000, more preferably 500 to 5,000, and particularly preferably 500 to 3,000, from the viewpoint of the flexibility and thermal stability of the polyurethane-based thermoplastic elastomer. .. The mass ratio (x: y) of the hard segment (x) and the soft segment (y) is preferably 15:85 to 90:10, more preferably 30:70 to 90:10 from the viewpoint of moldability. ..

The polyurethane-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method. As the polyurethane-based thermoplastic elastomer, for example, the thermoplastic polyurethane described in JP-A-5-331256 can be used.

As the polyurethane-based thermoplastic elastomer, specifically, a combination of a hard segment made of an aromatic diol and an aromatic diisocyanate and a soft segment made of a polycarbonate is preferable, and more specifically, a tolylene diisocyanate ( TDI) / polyester type polyol copolymer, TDI / polyether type polyol copolymer, TDI / caprolactone type polyol copolymer, TDI / polycarbonate type polyol copolymer, 4,4′-diphenylmethane diisocyanate (MDI) / polyester -Based polyol copolymer, MDI / polyether-based polyol copolymer, MDI / caprolactone-based polyol copolymer, MDI / polycarbonate-based polyol copolymer, and MDI + hydroquinone / polyhexamethyi At least one selected from the group consisting of carbonate copolymers is preferable, and TDI / polyester polyol copolymer, TDI / polyether polyol copolymer, MDI / polyester polyol copolymer, MDI / polyether polyol At least one selected from the group consisting of a copolymer and an MDI + hydroquinone / polyhexamethylene carbonate copolymer is more preferable.

Examples of commercially available polyurethane-based thermoplastic elastomers include "Elastollan" series manufactured by BASF (for example, ET680, ET880, ET690, ET890, etc.) and "Kuramilon U" series manufactured by Kuraray Co., Ltd. (for example, , 2000-series, 3000-series, 8000-series, 9000-series, etc.), "Miractran" series manufactured by Nippon Miractolan Co., Ltd. (eg, XN-2001, XN-2004, P390RSUP, P480RSUI, P26MRNAT, E490, E590, P890 etc.) Etc. can be used.

(Polyolefin thermoplastic elastomer)
As the thermoplastic polyolefin-based elastomer, for example, at least polyolefin forms crystalline hard segments having a high melting point, and other polymers (eg, polyolefin, other polyolefins, polyvinyl compounds, etc.) are amorphous and have a glass transition temperature of The material forming the low soft segment may be mentioned. Examples of the polyolefin forming the hard segment include polyethylene, polypropylene, isotactic polypropylene, polybutene and the like.

Examples of the thermoplastic polyolefin-based elastomer include olefin-α-olefin random copolymers and olefin block copolymers. Specific examples include propylene block copolymers, ethylene-propylene copolymers and propylene- 1-hexene copolymer, propylene-4-methyl-1 pentene copolymer, propylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-pentene copolymer, ethylene- 1-butene copolymer, 1-butene-1-hexene copolymer, 1-butene-4-methyl-pentene, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate Copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer Polymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, propylene-methacrylic acid copolymer, propylene-methyl methacrylate copolymer, propylene-ethyl methacrylate copolymer, propylene-butyl methacrylate copolymer Examples thereof include polymers, propylene-methyl acrylate copolymers, propylene-ethyl acrylate copolymers, propylene-butyl acrylate copolymers, ethylene-vinyl acetate copolymers and propylene-vinyl acetate copolymers.

Among them, the thermoplastic polyolefin-based elastomers include propylene block copolymers, ethylene-propylene copolymers, propylene-1-hexene copolymers, propylene-4-methyl-1pentene copolymers, propylene-1- Butene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-pentene copolymer, ethylene-1-butene copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer , Ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, propylene-methacrylic acid copolymer , Propylene-methyl methacrylate copolymer, Ropylene-ethyl methacrylate copolymer, propylene-butyl methacrylate copolymer, propylene-methyl acrylate copolymer, propylene-ethyl acrylate copolymer, propylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, And at least one selected from the group consisting of propylene-vinyl acetate copolymer, ethylene-propylene copolymer, propylene-1-butene copolymer, ethylene-1-butene copolymer, ethylene-methyl methacrylate At least one selected from the group consisting of a copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-butyl acrylate copolymer is more preferable.
Further, two or more kinds of olefin resins such as ethylene and propylene may be used in combination. The content of the olefin resin in the thermoplastic polyolefin-based elastomer is preferably 50% by mass or more and 100% by mass or less.

The number average molecular weight of the thermoplastic polyolefin-based elastomer is preferably 5,000 to 10,000,000. When the number average molecular weight of the thermoplastic polyolefin-based elastomer is 5,000 to 10,000,000, the thermoplastic resin material has sufficient mechanical properties and excellent processability. From the same viewpoint, the number average molecular weight of the polyolefin-based thermoplastic elastomer is more preferably 7,000 to 1,000,000, and particularly preferably 10,000 to 1,000,000. Thereby, the mechanical properties and processability of the thermoplastic resin material can be further improved. The number average molecular weight of the polymer forming the soft segment is preferably 200 to 6000 from the viewpoint of toughness and low temperature flexibility. Further, the mass ratio (x: y) of the hard segment (x) and the soft segment (y) is preferably 50:50 to 95:15, more preferably 50:50 to 90:10 from the viewpoint of moldability. ..
The thermoplastic polyolefin-based elastomer can be synthesized by copolymerization by a known method.

Moreover, as the polyolefin-based thermoplastic elastomer, one obtained by acid-modifying a polyolefin-based thermoplastic elastomer may be used.
The "acid-modified polyolefin-based thermoplastic elastomer" refers to a polyolefin-based thermoplastic elastomer to which an unsaturated compound having an acidic group such as a carboxylic acid group, a sulfuric acid group or a phosphoric acid group is bonded.
To bond an unsaturated compound having an acidic group such as a carboxylic acid group, a sulfuric acid group, and a phosphoric acid group to the polyolefin-based thermoplastic elastomer, for example, a polyolefin-based thermoplastic elastomer, as an unsaturated compound having an acidic group, Examples thereof include bonding (for example, graft polymerization) of unsaturated bond sites of unsaturated carboxylic acid (generally maleic anhydride).
As the unsaturated compound having an acidic group, an unsaturated compound having a carboxylic acid group, which is a weak acid group, is preferable from the viewpoint of suppressing deterioration of the thermoplastic polyolefin-based elastomer. Examples of the unsaturated compound having a carboxylic acid group include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and the like.

Examples of commercially available polyolefin-based thermoplastic elastomers include "Toughmer" series manufactured by Mitsui Chemicals, Inc. (for example, A0550S, A1050S, A4050S, A1070S, A4070S, A35070S, A1085S, A4085S, A7090, A70090, MH7007, MH7010). , XM-7070, XM-7080, BL4000, BL2481, BL3110, BL3450, P-0275, P-0375, P-0775, P-0180, P-0280, P-0480, P-0680, etc.), Mitsui DuPont "Nucrel" series manufactured by Polychemical Co., Ltd. (for example, AN4214C, AN4225C, AN42115C, N0903HC, N0908C, AN42012C, N410, N1050H, N11). 8C, N1110H, N1207C, N1214, AN4221C, N1525, N1560, N0200H, AN4228C, AN4213C, N035C, etc. "Elvalloy AC" series (for example, 1125AC, 1209AC, 1218AC, 1609AC, 1820AC, 1913AC, 2112AC, 2116AC, 2615AC, 2715AC, 3117AC, 3427AC, 3717AC, etc.), Sumitomo Chemical Co., Ltd.'s "Aklift" series, "Evatate" series, etc., Tosoh Corporation's "Ultrasen" series, etc., Prime Polymer "Prime TPO" series ( For example, E-2900H, F-3900H, E-2900, F-3900, J-5900, E-2910, F-3910, J-5910, E-2710 F-3710, J-5910, E-2740, F-3740, R110MP, R110E, can be used T310E, also M142E, etc.) and the like.

-Thermoplastic resin-
(Polyester thermoplastic resin)
Examples of the polyester-based thermoplastic resin include polyesters that form the hard segment of the above-mentioned polyester-based thermoplastic elastomer.
Specific examples of the polyester-based thermoplastic resin include polylactic acid, polyhydroxy-3-butylbutyric acid, polyhydroxy-3-hexylbutyric acid, poly (ε-caprolactone), polyenanthlactone, polycaprylolactone, and polybutylene. Examples thereof include aliphatic polyesters such as adipate and polyethylene adipate, and aromatic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polybutylene naphthalate. Among these, polybutylene terephthalate is preferable as the polyester thermoplastic resin from the viewpoint of heat resistance and processability.

Commercially available polyester-based thermoplastic resins include, for example, "Duranex" series manufactured by Polyplastics Co., Ltd. (for example, 2000, 2002, etc.) and "Novaduran" series manufactured by Mitsubishi Engineering Plastics Co., Ltd. (for example, 5010R5). , 5010R3-2, etc.), “Toraycon” series manufactured by Toray Industries, Inc. (eg, 1401X06, 1401X31, etc.) and the like can be used.

(Polyamide thermoplastic resin)
Examples of the polyamide-based thermoplastic resin include polyamides that form the hard segment of the above-mentioned polyamide-based thermoplastic elastomer.
Specific examples of the polyamide-based thermoplastic resin include polyamide obtained by ring-opening polycondensation of ε-caprolactam (amide 6), polyamide obtained by ring-opening polycondensation of undecane lactam (amide 11), ring-opening polycondensation of lauryl lactam. Examples thereof include polyamide (amide 12), polyamide (amide 66) obtained by polycondensing diamine and dibasic acid, and polyamide (amide MX) having metaxylene diamine as a constituent unit.

The amide 6 can be represented by, for example, {CO— (CH ₂ ) ₅ —NH} _n . The amide 11 can be represented by, for example, {CO— (CH ₂ ) ₁₀ —NH} _n . The amide 12 can be represented by, for example, {CO— (CH ₂ ) ₁₁ —NH} _n . The amide 66 can be represented by, for example, {CO (CH ₂ ) ₄ CONH (CH ₂ ) ₆ NH} _n . The amide MX can be represented by, for example, the following structural formula (A-1). Here, n represents the number of repeating units.

 

As a commercially available product of amide 6, for example, "UBE nylon" series (for example, 1022B, 1011FB, etc.) manufactured by Ube Industries, Ltd. can be used. As a commercially available product of amide 11, for example, “Rilsan B” series manufactured by Arkema Ltd. can be used. As a commercially available product of the amide 12, for example, "UBE nylon" series (for example, 3024U, 3020U, 3014U, etc.) manufactured by Ube Industries, Ltd. can be used. As a commercially available product of the amide 66, for example, "Leona" series (for example, 1300S, 1700S, etc.) manufactured by Asahi Kasei Co., Ltd. can be used. As a commercially available product of amide MX, for example, "MX Nylon" series (for example, S6001, S6021, S6011, etc.) manufactured by Mitsubishi Gas Chemical Co., Inc. can be used.

The thermoplastic polyamide-based resin may be a homopolymer formed of only the above structural unit or a copolymer of the above structural unit and another monomer. In the case of a copolymer, the content of the above structural units in each polyamide-based thermoplastic resin is preferably 40% by mass or more.

(Polyolefin thermoplastic resin)
Examples of the polyolefin-based thermoplastic resin include the polyolefins that form the hard segments of the above-mentioned polyolefin-based thermoplastic elastomer.
Specific examples of the polyolefin-based thermoplastic resin include polyethylene-based thermoplastic resin, polypropylene-based thermoplastic resin, polybutadiene-based thermoplastic resin, and the like. Among these, polypropylene-based thermoplastic resin is preferable as the polyolefin-based thermoplastic resin from the viewpoint of heat resistance and processability.
Specific examples of the polypropylene-based thermoplastic resin include propylene homopolymer, propylene-α-olefin random copolymer, propylene-α-olefin block copolymer and the like. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, Examples thereof include α-olefins having about 3 to 20 carbon atoms such as 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene.

-Other ingredients-
In addition to the resin, the resin material may contain other components such as additives within a range that does not impair the effect. Examples of other components include rubber, various fillers (eg, silica, calcium carbonate, clay, etc.), antioxidants, oils, plasticizers, coloring agents, weathering agents, and the like.

<Production of tire>
Next, an example of a method for manufacturing the tire 10 will be described.
First, an unvulcanized inner liner 16, an unvulcanized side reinforcing rubber 24, a carcass 14 including an unvulcanized rubber material, a bead core 26, and a bead filler 28 are provided on the outer periphery of a known tire forming drum (not shown). Forming an unvulcanized tire case.

On the other hand, the belt layer 40 is formed as follows.
Specifically, the resin coating cord 42 is sent toward the outer peripheral surface of the belt forming drum (not shown). The resin coating cord 42 is pressed against the outer peripheral surface of the belt forming drum in a state where the coating resin 42S is heated by hot air and melted, and then cooled. In this manner, the resin-coated cord 42 is spirally wound around the outer peripheral surface of the belt forming drum and pressed against the outer peripheral surface, whereby a layer of the resin coated cord 42 is formed on the outer peripheral surface of the belt forming drum.

Next, the belt layer 40 in which the resin coating cord 42 is cooled and the coating resin 42S is solidified is removed from the belt forming drum. Then, after the adhesive is applied to the inner peripheral surface of the removed belt layer 40 as required, the belt layer 40 is arranged on the tire molding drum in the radial direction outside of the unvulcanized tire case. Then, the unvulcanized tire case is expanded, and the outer peripheral surface of the tire case, in other words, the outer peripheral surface of the carcass 14 is pressure-bonded to the inner peripheral surface of the belt layer 40.
Finally, an adhesive is applied to the outer peripheral surface of the belt layer 40 as needed, and then the unvulcanized tread 20 is attached to complete the green tire.
The green tire manufactured in this way is vulcanized and molded by the vulcanization mold to complete the tire 10.

Although examples of the embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments, and various other embodiments are possible.

Note that one embodiment of the present disclosure includes the aspects described below.
<1> A pair of bead cores,
A carcass straddling the pair of bead cores, the end portion of which is locked to the bead core,
An inner liner provided on the tire inner surface side of the carcass, wherein the content of the diene rubber is 20% by mass or more based on the total amount of rubber contained in the inner liner,
A side reinforcing rubber layer provided in direct contact with the inner liner between the carcass of the tire side portion and the inner liner, and extending in the tire radial direction along the inner surface of the carcass,
A belt layer provided on the outer side in the tire radial direction of the carcass, having a cord and a cord coating layer that coats the cord and contains a resin,
A tread provided on the tire radial direction outer side of the belt layer,
Run-flat tire with.
<2> The run-flat tire according to <1>, wherein the diene rubber contained in the inner liner contains natural rubber.
<3> The run-flat tire according to <1> or <2>, wherein the inner liner further contains butyl rubber.
<4> The run-flat tire according to any one of <1> to <3>, in which the side reinforcing rubber layer contains a diene rubber.
<5> The run flat according to any one of <1> to <4>, which is arranged so as to extend from the bead core to a tire radial direction outer side along an outer surface of the carcass and further includes a bead filler containing a resin. tire.
<6> The run flat tire according to any one of <1> to <5>, wherein the bead core has a bead wire and a bead coating layer that covers the bead wire and contains a resin.

Hereinafter, the present disclosure will be specifically described by way of examples, but the present disclosure is not limited to these descriptions. In addition, "part" represents a mass standard unless otherwise specified.

[Example 1]
<Preparation of coated resin cord>
An adhesive (made by Mitsubishi Chemical Co., Ltd.) that was heated and melted into a multifilament having an average diameter of φ1.15 mm (a monofilament having a diameter of 0.35 mm (steel, strength: 280 N, elongation: 3%) twisted wire of 7 pieces) , Maleic anhydride-modified polyester-based thermoplastic elastomer, product name: Primalloy-AP GQ730). Then, a coating resin (a polyester thermoplastic elastomer manufactured by Toray-Dupont Co., Ltd., product name: Hytrel 5557) extruded by an extruder is attached to the outer periphery of the resin to coat and cool it. The extrusion conditions are that the temperature of the metal member is 200 ° C., the temperature of the coating resin is 240 ° C., and the extrusion speed is 30 m / min. The coated resin cord is produced as described above.

<Preparation of unvulcanized inner liner>
The following components are kneaded with a Banbury mixer (Mixtron BB MIXER, manufactured by Kobe Steel, Ltd.) and molded into a sheet shape to prepare an unvulcanized inner liner.
・ Natural rubber (“NR (PHR)” in Table 1): RSS # 3 ... 20 parts by mass Bromobutyl rubber (“Br-IIR (PHR)” in Table 1, bromobutyl 2225 trademark: manufactured by Exxon)・ ・ ・ 80 parts by mass ・ Carbon black N660 (trademark: manufactured by Degissa) ・ ・ ・ 45 parts by mass ・ Flat clay (POLYFIL DL trademark: manufactured by JH Huber) ・ ・ ・ 30 parts by mass ・ Process oil (aroma oil AROMAX # 1 Trademark: Fuji Kosan Co., Ltd ... 2 parts by mass

<Preparation of unvulcanized side reinforcing rubber>
The following components are kneaded and molded with a Banbury mixer (Mixtron BB MIXER, manufactured by Kobe Steel, Ltd.) to prepare an unvulcanized side reinforcing rubber.
・ Natural rubber: RSS # 3: 25 parts by mass ・ Butadiene rubber (BR): BR502, manufactured by JSR Co .: 75 parts by mass ・ Carbon black: FEF, Asahi Carbon Co .: 60 parts by mass ・ Anti-aging Agent: Antigen 6C, manufactured by Sumitomo Chemical Co., Ltd .... 2 parts by mass, vulcanization accelerator: Nocceller NS-P, manufactured by Ouchi Shinko Chemical Co., Ltd .... 3 parts by mass, vulcanization accelerator: Noxcellar TOT-N, Made by Ouchi Shinko Chemical Co., Ltd ... 2 parts by mass, sulfur ... 5 parts by mass

<Preparation of unvulcanized tread>
The following components are kneaded with a Banbury mixer (Mixtron BB MIXER, manufactured by Kobe Steel, Ltd.) and molded into a sheet shape to prepare an unvulcanized tread.
-Natural rubber: RSS # 3 ... 50 parts by mass-Styrene / butadiene copolymer rubber (SBR): # 1500 (emulsion polymerization SBR), manufactured by JSR ... 50 parts by mass-Carbon black: ISAF, Asahi Carbon Company-made: 50 parts by mass Anti-aging agent: Antigen 6C, Sumitomo Chemical Co., Ltd .: 1 part by mass-Vulcanization accelerator: Nocceller CZ, Ouchi Shinko Chemical Co., Ltd .: 0.5 parts by mass・ Vulcanization accelerator: Nocceller DM, manufactured by Ouchi Shinko Chemical Co., Ltd .... 1 part by mass ・ Vulcanization accelerator: Nocceller D, manufactured by Ouchi Shinko Chemical Co., Ltd .... 0.5 part by mass, sulfur・ 1.5 parts by mass

<Production of tire>
An unvulcanized tire case and belt layer are prepared according to the above-described embodiments.
As the bead core, as shown in FIG. 2, one steel wire (φ2.1 mm) coated with a coating resin (thermoplastic polyester elastomer, manufactured by Toray DuPont, product name: Hytrel 5557) is wound. Use the one that you made. As the bead filler, a bead filler made of a polyester thermoplastic elastomer (manufactured by Toray-Dupont, product name: Hytrel 5557) is used. As the carcass, an organic fiber cord covered with a diene rubber (natural rubber) is used.
A belt layer is installed on the outer peripheral surface of an unvulcanized tire case, and an unvulcanized tread is wound around the outer periphery of the belt layer to obtain a raw tire. Then, the obtained raw tire is vulcanized by heating at 160 ° C. for 20 minutes to obtain a tire.

<Evaluation>
(Run-flat runnability (durability) evaluation)
In an indoor drum test based on the ISO standard, run flat running at an internal pressure of 0 kPa and a speed of 80 km / h. The traveling distance until the traveling becomes impossible due to a tire failure or a support failure is measured, and an index when the traveling distance in Comparative Example 1 is 100 is obtained. The results are shown in Table 1. It should be noted that the larger the index, the better the run-flat running property (that is, the durability).

(Internal pressure retention evaluation)
A tire obtained by assembling a molded tire on a rim and filling the inside of the tire with air to an internal pressure of 0.3 MPa is left in a thermo-hygrostat for 3 months while being kept in an environment of 40 ° C / 50% RH. To do. The internal pressure holding ratio is obtained from the ratio of the internal pressure after leaving to the internal pressure before leaving, and the index when the internal pressure holding ratio in Comparative Example 1 is 100 is obtained. The results are shown in Table 1. The larger the index, the better the internal pressure retention.

[Example 2]
In the production of the unvulcanized inner liner, the tire is produced and evaluated in the same manner as in Example 1 except that the addition amount of natural rubber is 50 parts by mass and the addition amount of bromobutyl rubber is 50 parts by mass.

[Example 3]
In the production of the unvulcanized inner liner, the tire is produced and evaluated in the same manner as in Example 1 except that the addition amount of natural rubber is 80 parts by mass and the addition amount of bromobutyl rubber is 20 parts by mass.

[Comparative Example 1]
In the production of the coated resin cord, the coated rubber (natural rubber) is used instead of the coated resin, and in the production of the unvulcanized inner liner, the addition amount of the natural rubber is 0 part by mass and the addition amount of the bromobutyl rubber is 100 parts by mass A tire is manufactured and evaluated in the same manner as in Example 1 except that a coated rubber (natural rubber) is used instead of the coating resin in the bead core and a bead filler made of rubber (natural rubber) is used as the bead filler.

[Comparative example 2]
In the production of the coated resin cord, a tire was prepared in the same manner as in Example 1 except that a coated rubber was used instead of the coated resin, a coated rubber was used instead of the coated resin in the bead core, and a bead filler made of rubber was used as a bead filler. The production and evaluation of

[Comparative Example 3]
In the production of the coated resin cord, a tire was prepared in the same manner as in Example 2 except that a coated rubber was used instead of the coated resin, a coated rubber was used instead of the coated resin in the bead core, and a bead filler made of rubber was used as a bead filler. The production and evaluation of

 

Note that the numerical values of the durability evaluation and the internal pressure retention evaluation shown in Table 1 above are all prediction data by simulation.

The disclosure of Japanese Patent Application No. 2018-210297 filed on Nov. 8, 2018 is incorporated herein by reference in its entirety.
All publications, patent applications, and technical standards mentioned herein are to the same extent as if each individual publication, patent application, and technical standard were specifically and individually noted to be incorporated by reference, Incorporated herein.

The description of the reference numerals is as follows.
10 ... Tire (run flat tire), 12 ... Bead part, 14 ... Carcass, 16 ... Inner liner, 18 ... Tread part, 20 ... Tread, 22 ... Tire side part, 24 ... Side reinforcement rubber, 26 ... Bead core, 28 ... Bead filler, 30 ... rim, 40 ... Belt layer, 42 ... Resin coated cord

Claims (6)

1. A pair of bead cores,
   A carcass straddling the pair of bead cores, the end portion of which is locked to the bead core,
   An inner liner provided on the tire inner surface side of the carcass, wherein the content of the diene rubber is 20% by mass or more based on the total amount of rubber contained in the inner liner,
   A side reinforcing rubber layer provided in direct contact with the inner liner between the carcass of the tire side portion and the inner liner, and extending in the tire radial direction along the inner surface of the carcass,
   A belt layer provided on the outer side in the tire radial direction of the carcass, having a cord and a cord coating layer that coats the cord and contains a resin,
   A tread provided on the tire radial direction outer side of the belt layer,
   Run-flat tire with.
2. The run-flat tire according to claim 1, wherein the diene rubber contained in the inner liner contains natural rubber.
3. The run-flat tire according to claim 1 or 2, wherein the inner liner further contains butyl rubber.
4. The run-flat tire according to any one of claims 1 to 3, wherein the side reinforcing rubber layer contains a diene rubber.
5. The run-flat tire according to any one of claims 1 to 4, further comprising a bead filler containing a resin, the bead filler being arranged so as to extend from the bead core outward in the tire radial direction along the outer surface of the carcass.
6. The run-flat tire according to any one of claims 1 to 5, wherein the bead core includes a bead wire and a bead coating layer that covers the bead wire and contains a resin.

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