JP2010095150A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of attaining high durability by improving heat radiation. <P>SOLUTION: The pneumatic tire includes: a tread portion; a pair of bead portions; a carcass which includes a pair of sidewalls extending to between the tread portion and each bead portion and reinforces each thereof, extending to between the pair of bead portions in a toroid form; and an inner liner provided inside the carcass. In the pneumatic tire, a turbulent flow generation portion having a protrusion portion is formed on at least a part of a surface of the sidewall portion, and a thermoplastic resin film is used in an inner liner. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire capable of improving durability by suppressing temperature rise.

  In general, an increase in the tire temperature of a pneumatic tire is not preferable from the viewpoint of tire durability because it causes a change over time such as a change in material properties and a tread breakage during high-speed running.

  In particular, in a run flat tire during puncturing (when traveling with an internal pressure of 0 kPa), reducing the tire temperature is a major issue in order to improve durability. This is because, for example, in a run-flat tire having a crescent-shaped reinforcing rubber, deformation in the tire radial direction concentrates on the reinforcing rubber during puncturing and the portion reaches a very high temperature, which greatly affects durability. .

  On the other hand, a tire using a reinforcing member that reduces and suppresses distortion of the tire constituent member is known as a tire capable of reducing the tire temperature by suppressing heat generation from the tire constituent member. However, the use of such a reinforcing member may cause an unintended failure, and in a run-flat tire, the normal spring performance during normal internal pressure running is increased to deteriorate the ride comfort. May have adverse effects.

Therefore, as a tire capable of reducing the tire temperature without impairing the normal performance, for example, a long protrusion (protrusion) or groove in the tire radial direction described in Patent Document 1 is provided on the outer surface of the tire to provide a cooling effect. Improved tires are used. As can be seen from the fact that rubber is a material with poor thermal conductivity, this tire has a cooling effect by promoting the generation of turbulence in the air flow on the outer surface of the tire rather than by improving the cooling effect by expanding the heat radiation area. A tire intended to improve the effect.
International Publication No. 2007/032405 Pamphlet

  However, even in the case of a pneumatic tire that promotes heat dissipation as described above and has improved durability, further improvements in heat dissipation efficiency and durability are desired in order to more reliably reduce the occurrence of failure.

  An object of the present invention is to advantageously solve the above problems, and a pneumatic tire according to the present invention extends between a tread portion, a pair of bead portions, and the tread portion and each bead portion. A pneumatic tire having a pair of sidewall portions, a carcass extending in a toroidal shape between the pair of bead portions to reinforce these portions, and an inner liner provided inside the carcass In this embodiment, a turbulent flow generating portion having a protrusion is provided on at least a part of the surface of the sidewall portion, and a thermoplastic resin film is used for the inner liner. As described above, by providing the turbulent flow generation portion in the sidewall portion where failure is likely to occur, the heat dissipation of the sidewall portion can be promoted by the turbulent flow of air generated in the turbulent flow generation portion. Also, by using a thermoplastic resin film for the inner liner that exists in the innermost part of the tire with the greatest bending deformation, heat generation of the inner liner is reduced compared to the case where a rubber sheet with poor thermal conductivity is used for the inner liner. The tire temperature rise can be reduced. And, since the temperature is involved nonlinearly in the fatigue fracture characteristics of the tire constituent members, the tire durability performance is improved as the absolute temperature of the tire is lower even with the same temperature reduction effect. Therefore, according to the present invention, the thermoplastic resin film The synergistic effect of use and installation of the turbulent flow generator improves tire durability.

  Here, since the rubber constituting the tire is a material with poor thermal conductivity, the protrusion of the turbulent flow generation part promotes the generation of turbulent flow rather than the effect of enlarging the heat dissipation area and promoting heat dissipation. It is considered that the effect of accelerating heat dissipation by applying air turbulence directly to the sidewall portion is greater. And in this invention, generation | occurrence | production of a tire failure can be suppressed by providing a protrusion in the vicinity surface of the location where a failure is likely to occur, and the present invention particularly provides a sidewall portion where the end of the carcass is located. The temperature of the sidewall portion is reduced by applying it to a pneumatic tire having a structure in which failure is likely to occur in the sidewall portion, such as a run-flat tire having a sidewall portion provided with a TBR having a crescent-shaped reinforcing rubber. The effect can be enhanced.

  Here, in the pneumatic tire according to the present invention, the turbulent flow generation portion includes a plurality of protrusions, the height of the protrusion is h, the width is w, and the protrusions in the turbulent flow generation portion are between the protrusions. When the pitch is p, it is preferable to satisfy the relationship of 1.0 ≦ p / h ≦ 50.0 and 1.0 ≦ (p−w) /w≦100.0. The state of the air flow (turbulent flow) can be roughly organized at p / h. However, if the pitch (p) is too narrow, the air flow does not enter between the protrusions, and the heat dissipation efficiency hardly increases. If the pitch (p) is excessively widened, a region where the influence of the change in the air flow due to the provision of the protrusions does not reach occurs, and the heat dissipation efficiency hardly increases. Moreover, when (pw) / w which shows the ratio of the width | variety (w) of a protrusion with respect to pitch (p) is made too small, with respect to the area of the surface which wants to improve heat dissipation, the protrusion (surface area increase) which consists of rubber | gum The surface area of the portion where the heat dissipation effect cannot be increased due to the increase in the surface area may increase, and the heat generation may increase due to the increase in the rubber volume.

  In the pneumatic tire of the present invention, the ratio (p / h) of the pitch (p) to the height (h) is preferably 2.0 ≦ p / h ≦ 24.0, and 10.0 ≦ More preferably, p / h ≦ 20.0. In the pneumatic tire according to the present invention, the (pw) / w preferably satisfies 4.0 ≦ (pw) /w≦39.0. By setting p / h and (p−w) / w within this range, it is possible to further improve the heat transfer coefficient on the surface of the sidewall portion where the turbulent flow generation portion is provided, and to reduce the tire temperature.

  In the pneumatic tire of the present invention, the height (h) of the protrusion is preferably 0.5 mm ≦ h ≦ 7 mm, and the width (w) of the protrusion is preferably 0.3 mm ≦ h ≦ 4 mm. This is because a protrusion having a height (h) and a width (w) in this range has a high effect of improving the heat dissipation efficiency and a high tire temperature reduction effect.

  In the pneumatic tire of the present invention, the angle θ formed by the extending direction of the protrusion with respect to the tire radial direction is preferably −70 ° ≦ θ ≦ 70 °, and −45 ° ≦ θ ≦ 45 °. More preferably, it is most preferable that −20 ° ≦ θ ≦ 20 °. By prescribing the extending direction of the protrusions as described above, it is possible to reduce the concern about the increase in heat generation and heat storage at the protrusions of the turbulent flow generation part.

  In the pneumatic tire of the present invention, it is preferable that the width of the upper portion of the protrusion is smaller than the width of the lower portion of the protrusion at least at the inner end in the tire radial direction. Since the pneumatic tire is a rotating body, the air flow on the surface of the sidewall portion is slightly toward the outside in the tire radial direction due to centrifugal force. By reducing the width of the upper part from the width, that is, by forming an inclined surface that is inclined inwardly in the tire circumferential direction from the lower part to the upper part of the protrusion, and providing the top part to the protrusion, This is because it is possible to reduce the stagnation portion on the back side of the protrusion with respect to the inflow of air and improve the heat dissipation. Further, by additionally providing the top portion, a three-dimensional flow is generated, and the heat dissipation effect can be further improved locally.

  In the pneumatic tire of the present invention, an angle θ formed by the extending direction of the protrusion with respect to the tire radial direction may vary depending on the position in the tire radial direction. On the surface of the rotating pneumatic tire, the flow velocity of the air flow varies depending on the position in the tire radial direction. Therefore, it is preferable to change the angle in the extending direction of the protrusion at an arbitrary position in the tire radial direction.

  In the pneumatic tire of the present invention, the protrusion may be discontinuously divided along the extending direction. When a protrusion is provided on the surface of the side wall, a portion of the heat radiation is worse than when no protrusion is provided because stagnation occurs on the back side of the protrusion with respect to the inflow of air into the protrusion. However, by dividing the protrusion of the turbulent flow generation portion discontinuously, it is possible to reduce the portion where the heat dissipation deteriorates and improve the average heat transfer coefficient.

  In the pneumatic tire of the present invention, the protrusions may be non-uniformly arranged along the tire circumferential direction. The heat transfer rate depends on the air flow rate, and the pneumatic tire is a rotating body, and the flow rate of the air flowing on the surface of the sidewall portion varies depending on the position in the tire radial direction. Therefore, by disposing the protrusions non-uniformly along the tire circumferential direction, the radial heat dissipation efficiency can be made uniform.

  In the pneumatic tire of the present invention, the sidewall portion may include a crescent-shaped reinforcing rubber. The pneumatic tire of the present invention may be a heavy duty tire. According to the present invention, it is possible to reduce the temperature of the maximum bent portion of the reinforcing rubber and the temperature near the end of the carcass, thereby improving the durability of the tire and reducing the occurrence of failure.

  In the pneumatic tire of the present invention, the thermoplastic resin film used for the inner liner is made from a modified ethylene-vinyl alcohol copolymer (B) obtained by reacting an ethylene-vinyl alcohol copolymer (A). It is preferable to include at least a layer made of a resin composition (D) obtained by dispersing a flexible resin (C) having a Young's modulus at 23 ° C. smaller than the modified ethylene-vinyl alcohol copolymer (B) in the matrix. . Here, the thermoplastic resin film of the pneumatic tire of the present invention is required to include at least a layer composed of the resin composition (D), and may further include another layer, or the resin composition. You may be comprised only from the layer which consists of (D). In the resin composition (D), the modified ethylene-vinyl alcohol copolymer (B) exists as a matrix, and the matrix means a continuous phase. As described above, when the thermoplastic resin film including at least the layer made of the resin composition (D) is used as the inner liner for the pneumatic tire described above, the layer made of the resin composition (D) is excellent in gas barrier properties and flex resistance. Since it is a lightweight layer, it is possible to provide a lightweight pneumatic tire with significantly improved internal pressure retention.

  In the pneumatic tire of the present invention, the flexible resin (C) preferably has a Young's modulus at 23 ° C. of 500 MPa or less. In the pneumatic tire of the present invention, the flexible resin (C) preferably has a functional group that reacts with a hydroxyl group.

  In the pneumatic tire of the present invention, the content of the flexible resin (C) in the resin composition (D) is preferably in the range of 10 to 80% by mass, and the average particle of the flexible resin (C) The diameter is preferably 2 μm or less.

  In the pneumatic tire of the present invention, the layer made of the resin composition (D) may be crosslinked.

Furthermore, in the pneumatic tire of the present invention, the layer made of the resin composition (D) has an oxygen transmission rate of 3.0 × 10 ⁻¹² cm ³ · cm ² · sec ² · 20 ° C. and 65% RH. The thickness is preferably cmHg or less, and the thickness of the layer made of the resin composition (D) is preferably 100 μm or less. Here, the oxygen transmission rate can be measured according to, for example, JIS K7126 (isobaric method).

  ADVANTAGE OF THE INVENTION According to this invention, the heat dissipation effect increases by the synergistic effect of use of a thermoplastic resin film, and installation of a turbulent flow generation part, and the pneumatic tire which the durability performance improved can be provided.

  Hereinafter, embodiments of a pneumatic tire according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
Here, FIG. 1 is a side view of the run-flat tire 1 of the first embodiment of the pneumatic tire of the present invention, FIG. 2 is a perspective view of the main part of the run-flat tire 1, and FIG. FIG. 4 is a perspective view of the main part of the turbulent flow generating part 5 provided on the sidewall part 3 of the run-flat tire 1, and FIG. 5 is a cross-sectional view of the turbulent flow generating part 5. 6 is a side view of the protrusion of the turbulent flow generation part 5 as seen from the tire circumferential direction.

(Run flat tire)
As shown in FIGS. 1 to 3, the run-flat tire 1 includes a tread portion 2 that comes into contact with the road surface, sidewall portions 3 on both sides of the tire, and bead portions 4 provided along the opening edges of the sidewall portions 3. And.

  The sidewall portion 3 is provided with five turbulent flow generating portions 5 intermittently in the tire circumferential direction as shown in FIG. Here, as shown in FIG. 3, the range (working region) of the sidewall portion 3 forming the turbulent flow generation portion 5 is 10 of the tire cross-section height (SH) from the base line of the rim (not shown). It is in the range of ˜90%.

  As shown in FIG. 1 and FIG. 2, the bead part 4 includes a bead core 6 </ b> A and a bead filler 6 </ b> B provided so as to go around along the edge of the opening of the sidewall part 3. A steel cord or the like is used as the bead core 6A.

  As shown in FIGS. 2 and 3, the run-flat tire 1 has a carcass layer 7 serving as a skeleton of the tire. A side wall reinforcing layer 8 that reinforces the side wall portion 3 is provided on the inner side in the tire width direction of the carcass layer 7 located in the side wall portion 3. Here, the sidewall reinforcing layer 8 is formed of a crescent-shaped rubber stock in a cross section in the tire width direction.

  A plurality of belt layers (steel belt reinforcing layers 9 and 10, circumferential reinforcing layer 11) are provided on the outer side in the tire radial direction of the carcass layer 7. A tread portion 2 that is in contact with the road surface is provided on the outer side in the tire radial direction of the circumferential reinforcing layer 11. An inner liner 14, which will be described in detail later, is provided on the inner side in the tire radial direction of the carcass layer 7 and the sidewall reinforcing layer 8.

(Turbulent flow generator)
As shown in FIGS. 2, 4, and 5, the turbulent flow generating portion 5 of the run-flat tire 1 has a plurality of protrusions extending on the outer surface of the sidewall portion 3 along substantially the same direction as the radial direction r. (Projection) 12 and a groove 13 between the projections 12 are provided. As shown in FIG. 5, the protrusions 12 are set to a predetermined pitch (p), and the height of the protrusions 12 is also set to the same height between the protrusions 12 adjacent in the tire circumferential direction. As shown in FIG. 5, the pitch (p) is a distance between points obtained by dividing the width at the center in the extending direction of the protrusion 12 into two equal parts.

  As shown in FIG. 6, in this embodiment, the center height (h2) of the protrusion 12 in the extending direction of the protrusion 12 (substantially the same as the tire radial direction r) is the end in the extending direction of the protrusion 12. The center in the extending direction is gradually raised so as to be higher than the height (h1). Hereinafter, the height (h) of the protrusion 12 refers to the height of the highest portion of the protrusion, that is, the center height (h2) in the present embodiment. In addition to the present embodiment, the height of the protrusion 12 may be uniform (the height of the end is equal to the height of the center).

  As described above, the turbulent flow generation part 5 is provided completely along the circumferential direction of the sidewall part 3, and the turbulent flow generation part 5 provided in at least a part of the sidewall part 3 has an angle θ It extends in the direction of In the present embodiment, the height (h), pitch (p), and width (w) of the protrusion 12 of the turbulent flow generation unit 5 are 1.0 ≦ p / h ≦ 50.0 and 1.0. The relationship of ≦ (p−w) /w≦100.0 is satisfied. In addition to this embodiment, the ratio (p / h) between the pitch (p) and the height (h) of the protrusions is preferably 2.0 ≦ p / h ≦ 24.0, more preferably 10. If 0 ≦ p / h ≦ 20.0, the heat transfer coefficient of the sidewall portion surface can be further improved.

  In this embodiment, by providing the turbulent flow generating portion 5 in the sidewall portion 3 where deterioration is likely to occur as compared with other portions, the sidewall portion is caused by the turbulent flow of air generated in the turbulent flow generating portion 5. 3 heat dissipation can be promoted. This is because the rubber constituting the tire is a material with poor thermal conductivity, so rather than expanding the heat dissipation area and promoting heat dissipation, it promotes the generation of turbulent flow and directs the turbulent air flow directly to the sidewall part. It is thought that this is because the heat radiation effect by applying is great.

  And, in particular, the side wall portion compared to other parts in long-term use, such as a heavy load tire, a run flat tire having a side wall portion 3 provided with a crescent-shaped reinforcing rubber, and a TBR (truck bus radial) In the pneumatic tire provided with a portion in which a failure is likely to occur in 3, the effect of reducing the temperature of the sidewall portion 3 is enhanced.

  Note that the air flow (turbulent flow) defined by p / h as described above has a fine pitch (p), that is, if the pitch (p) is narrowed, the air flow does not enter and the pitch (p ) Is too wide, it is equivalent to the case where there is no shape processing of the turbulent flow generation part, so p / h is preferably in the above numerical range.

  Further, (p−w) / w indicates the ratio of the protrusion to the pitch (p), and if this is too small, the ratio of the surface area of the protrusion 12 to the area of the surface on which heat dissipation is desired to be improved is equal. It is the same as becoming. The protrusion 12 is made of rubber, and since the effect of improving heat dissipation due to an increase in surface area cannot be expected, the minimum value of (p−w) / w is defined as 1.0.

  Moreover, as shown in FIG. 7, the extending direction of the protrusion 12 forms an angle θ with respect to the tire radial direction. Here, θ is an angle formed by the extending direction a at the center of the protrusion 12 and the tire radial direction, and is preferably in the range of −70 ° ≦ θ ≦ 70 °. Since the run-flat tire 1 is a rotating body, the air flow on the surface of the sidewall portion 3 is slightly outward in the radial direction due to centrifugal force. Therefore, in order to reduce the stagnation portion on the back side with respect to the inflow of air into the protrusion 12 and improve the heat dissipation, it is preferable to incline in the angular range with respect to the radial direction r.

  Here, the extending direction a of the turbulent flow generation unit 5 may be configured such that the angle θ formed with the tire radial direction r is different from the angle θ depending on the position along the predetermined tire radial direction r. In the rotating pneumatic tire (run flat tire 1), the flow velocity of the air flow varies depending on the radial position, and therefore the angle of the extending direction a of the turbulent flow generating portion 5 varies with respect to the radial direction r depending on the radial position. It is preferable to make it.

  In addition, the turbulent flow generation unit 5 may be configured to be discontinuously divided along the extending direction a. Moreover, the structure arrange | positioned nonuniformly along the tire circumferential direction may be sufficient as the turbulent flow generation part 5. By the way, when the protrusion is provided on the surface of the sidewall portion 3, the back side of the protrusion is stagnation with respect to the inflow of air, and there is a portion where heat dissipation is deteriorated as compared with the case where the protrusion is not provided. End up. In order to reduce the portion where the heat dissipation deteriorates and improve the average heat transfer coefficient, it is effective that the turbulent flow generating portion is divided discontinuously in the extending direction.

  And in this turbulent flow generation part 5, as shown in FIG. 5, with the rotation of the run-flat tire 1, the air flow S1 in contact with the sidewall part 3 where the turbulent flow generation part 5 is not formed is generated. The protrusion 12 is peeled off from the sidewall 3 and gets over the protrusion 12. At this time, an area S <b> 2 in which the air flow stays is generated on the back side of the protrusion 12. Then, the air flow S <b> 1 reattaches to the bottom (groove portion 13) between the next protrusion 12 and is peeled off again at the next protrusion 12. At this time, a region S3 in which the air flow stays is generated between the air flow S1 and the front surface of the next protrusion 12. Accordingly, the faster the air flow rate over the regions S2 and S3 where the air flow stays, the higher the heat dissipation rate.

  In addition, in this embodiment, although the turbulent flow generation | occurrence | production part 5 was arrange | positioned intermittently along the tire circumferential direction, you may arrange | position the protrusion 12 alternately uniformly over the perimeter.

(Inner liner)
The inner liner 14 is a flexible resin having a Young's modulus at 23 ° C. smaller than that of the modified ethylene-vinyl alcohol copolymer in a matrix made of a modified ethylene-vinyl alcohol copolymer obtained by reacting an ethylene-vinyl alcohol copolymer. A layer of a thermoplastic resin film made of a resin composition obtained by dispersing the resin is included. Such an inner liner 14 can be manufactured, for example, by the method disclosed in Japanese Patent Application Laid-Open No. 2008-24217 and used for the run flat tire 1 of the present embodiment. Specifically, the inner liner 14 is prepared as follows. The resin composition and an auxiliary layer and an adhesive layer can be used depending on the situation, and can be produced by a conventional method.

  Although the manufacturing method of the said modified ethylene-vinyl alcohol copolymer is not specifically limited, The manufacturing method with which an ethylene-vinyl alcohol copolymer and an epoxy compound are made to react in a solution is mentioned suitably. More specifically, a modified ethylene-vinyl alcohol copolymer is produced by adding an epoxy compound to a solution of an ethylene-vinyl alcohol copolymer in the presence of an acid catalyst or an alkali catalyst, preferably in the presence of an acid catalyst, and reacting. can do. Examples of the reaction solvent include aprotic polar solvents such as dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Examples of the acid catalyst include p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, sulfuric acid, and boron trifluoride. Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, lithium hydroxide, Examples include sodium methoxide. The catalyst amount is preferably in the range of 0.0001 to 10 parts by mass with respect to 100 parts by mass of the ethylene-vinyl alcohol copolymer.

  As said epoxy compound, a monovalent | monohydric epoxy compound is preferable. A divalent or higher-valent epoxy compound may crosslink with the ethylene-vinyl alcohol copolymer to generate gels, blisters, and the like, thereby reducing the quality of the inner liner. Note that glycidol and epoxypropane are particularly preferable among the monovalent epoxy compounds from the viewpoints of ease of production of the modified ethylene-vinyl alcohol copolymer, gas barrier properties, flex resistance, and fatigue resistance. Moreover, it is preferable that the said epoxy compound is made to react 1-50 mass parts with respect to 100 mass parts of ethylene-vinyl alcohol copolymers, It is still more preferable to react 2-40 mass parts, 5-35 mass parts It is more preferable to react.

  The modified ethylene-vinyl alcohol copolymer has a melt flow rate (MFR) of 0.1 to 30 g / 10 min under a load of 190 ° C. and 2160 g from the viewpoint of obtaining gas barrier properties, flex resistance and fatigue resistance. It is preferably 0.3 to 25 g / 10 minutes, more preferably 0.5 to 20 g / 10 minutes.

The flexible resin dispersed in the matrix composed of the modified ethylene-vinyl alcohol copolymer requires that the Young's modulus at 23 ° C. is smaller than that of the modified ethylene-vinyl alcohol copolymer, and is preferably 500 MPa or less. When the Young's modulus at 23 ° C. of the flexible resin is smaller than the modified ethylene-vinyl alcohol copolymer, the elastic modulus of the resin composition can be lowered, and as a result, the bending resistance can be improved. The flexible resin preferably has a functional group that reacts with a hydroxyl group. When the flexible resin has a functional group that reacts with a hydroxyl group, the flexible resin is uniformly dispersed in the modified ethylene-vinyl alcohol copolymer. Here, examples of the functional group that reacts with a hydroxyl group include a maleic anhydride residue, a hydroxyl group, a carboxyl group, and an amino group. Specific examples of the flexible resin having a functional group that reacts with a hydroxyl group include maleic anhydride-modified hydrogenated styrene-ethylene-butadiene-styrene block copolymer, maleic anhydride-modified ultra-low density polyethylene, and the like.

  Moreover, it is preferable that the content rate of the flexible resin in the said resin composition is the range of 10-80 mass%. When the content of the flexible resin is less than 10% by mass, the effect of improving the bending resistance is small, whereas when it exceeds 80% by mass, the gas barrier property may be deteriorated. Furthermore, the flexible resin preferably has an average particle size of 2 μm or less. If the average particle size exceeds 2 μm, the bending resistance of the layer made of the resin composition may not be sufficiently improved, and the gas barrier property may be lowered, and the internal pressure retention property of the tire may be deteriorated. In addition, the average particle diameter of the flexible resin in the resin composition is observed, for example, by freezing a sample, sectioning the sample with a microtome, and using a transmission electron microscope (TEM).

  The resin composition preferably has a Young's modulus at −20 ° C. of 1500 MPa or less. When the Young's modulus at −20 ° C. is 1500 MPa or less, durability when used in a cold district can be improved.

  The resin composition can be prepared by kneading a modified ethylene-vinyl alcohol copolymer and a flexible resin. The resin composition is preferably in the form of a film at the time of production of the inner liner, and the layer made of the resin composition is preferably 150 by melt molding, preferably extrusion molding such as T-die method or inflation method. It is formed into a film, sheet or the like at a melting temperature of ˜270 ° C. and used as an inner liner.

  The layer made of the resin composition is preferably crosslinked. When the layer made of the resin composition is not crosslinked, the inner liner is significantly deformed and becomes non-uniform in the vulcanization process of the tire, and the gas barrier property, flex resistance, and fatigue resistance of the inner liner may be deteriorated. Here, as a crosslinking method, a method of irradiating energy rays is preferable. Examples of the energy rays include ionizing radiation such as ultraviolet rays, electron beams, X-rays, α rays, γ rays, and among these, electron beams are used. Particularly preferred. The electron beam irradiation is preferably performed after the resin composition is processed into a molded body such as a film or sheet. Here, the dose of the electron beam is preferably in the range of 10 to 60 Mrad, and more preferably in the range of 20 to 50 Mrad. When the electron beam dose is less than 10 Mrad, the crosslinking is difficult to proceed. On the other hand, when the dose exceeds 60 Mrad, the molded body is likely to deteriorate.

Further, the layer made of the resin composition preferably has an oxygen transmission rate of 3.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less at 20 ° C. and 65% RH, 1.0. It is more preferably 10 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less, and further preferably 5.0 × 10 ⁻¹³ cm ³ · cm / cm ² · sec · cmHg or less. When the oxygen permeation amount at 20 ° C. and 65% RH exceeds 3.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg, when used as an inner liner, The layer made of the resin composition must be thick, and the weight of the tire cannot be reduced sufficiently.

  Furthermore, the thickness of the layer made of the resin composition is preferably 100 μm or less, more preferably the lower limit is 0.1 μm, still more preferably in the range of 1 to 40 μm, and in the range of 5 to 30 μm. It is more preferable that When the thickness of the layer made of the resin composition exceeds 100 μm, the effect of reducing the weight is reduced as compared to the conventional inner liner of butyl rubber when used as the inner liner, and the bending resistance and fatigue resistance are reduced. In addition, the bending deformation at the time of rolling of the tire tends to cause breakage and cracks, and the cracks are easily extended, so that the internal pressure retention property of the tire may be lower than before use. On the other hand, if it is less than 0.1 μm, the gas barrier property is insufficient, and the tire internal pressure retention property may not be sufficiently secured.

  The inner liner 14 of the present embodiment preferably further includes one or more auxiliary layers made of an elastomer adjacent to the layer made of the resin composition. Here, since the auxiliary layer uses an elastomer, it has high adhesion to the hydroxyl group of the modified ethylene-vinyl alcohol copolymer and is difficult to peel off from the layer made of the resin composition. Therefore, even if a rupture / crack occurs in the layer made of the resin composition, it is difficult for the crack to extend. Therefore, adverse effects such as a large rupture and crack can be suppressed, and the internal pressure retention of the tire can be sufficiently maintained. Moreover, the inner liner 14 can also be provided with one or more adhesive layers in at least one place between the layer made of the resin composition and the auxiliary layer and between the auxiliary layer and the auxiliary layer. Examples of the adhesive used in the adhesive layer include a chlorinated rubber / isocyanate adhesive.

  In addition, the inner liner 14 is formed as a laminated body, when an auxiliary | assistant layer and the adhesive bond layer as needed are provided other than the layer which consists of the said resin composition. Here, as a method for producing a laminate, for example, a method of laminating a layer made of a resin composition and another layer by coextrusion, a layer made of a resin composition and an auxiliary layer, if necessary, an adhesive Examples of the method include a method of bonding using a layer, and a method of bonding a layer made of a resin composition and an auxiliary layer on a drum using an adhesive layer as necessary when molding a tire.

The auxiliary layer preferably has an oxygen permeation rate of 3.0 × 10 ⁻⁹ cm ³ · cm / cm ² · sec · cmHg or less at 20 ° C. and 65% RH, and preferably 1.0 × 10 ⁻⁹ cm ^3. More preferably, it is not more than cm / cm ² · sec · cmHg. When the oxygen permeation amount at 20 ° C. and 65% RH is not more than 3.0 × 10 ⁻⁹ cm ³ · cm / cm ² · sec · cmHg, the effect of reinforcing the gas barrier property is sufficiently exerted, and the inner pressure retaining property of the tire is maintained. Can be maintained at a high level.

  Preferable examples of the elastomer used for the auxiliary layer include butyl rubber, halogenated butyl rubber, diene elastomer, and thermoplastic urethane elastomer. Here, from the viewpoint of gas barrier properties, butyl rubber and halogenated butyl rubber are preferable, and halogenated butyl rubber is more preferable. Also, butyl rubber and diene-based elastomers are preferable in order to suppress extension when cracks occur in the layer made of the resin composition. Furthermore, a thermoplastic urethane-based elastomer is preferable in order to suppress the generation and extension of cracks while reducing the thickness of the auxiliary layer. In addition, the auxiliary layer can be laminated, and it is particularly preferable to multilayer the auxiliary layer made of an elastomer having various characteristics. In addition, these elastomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the diene elastomer include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber. (CR) etc. are mentioned, Among these, natural rubber and butadiene rubber are preferable. These diene elastomers may be used alone or in combination of two or more.

  The thermoplastic urethane-based elastomer is obtained by a reaction of a polyol, an isocyanate compound, and a short chain diol. A polyol and a short chain diol form a linear polyurethane by an addition reaction with an isocyanate compound. Here, the polyol becomes a flexible part in the thermoplastic urethane elastomer, and the isocyanate compound and the short chain diol become a hard part. Note that the properties of thermoplastic urethane elastomers can be changed over a wide range by changing the type, blending amount, polymerization conditions, and the like of raw materials.

  The total thickness of the auxiliary layers is preferably in the range of 50 to 2000 μm, more preferably in the range of 100 to 1000 μm, and still more preferably in the range of 300 to 800 μm. When the total thickness of the auxiliary layers is less than 50 μm, the reinforcing effect is not sufficiently exerted, and it becomes difficult to suppress adverse effects when the layer made of the resin composition breaks or cracks. May not be sufficiently maintained. On the other hand, if the total thickness of the auxiliary layers exceeds 2000 μm, the weight of the tire increases.

  The auxiliary layer preferably has a tensile stress at 300% elongation of 10 MPa or less, more preferably 8 MPa or less, and even more preferably 7 MPa or less. When the tensile stress exceeds 10 MPa, the bending resistance and fatigue resistance may be reduced when the auxiliary layer is used for the inner liner.

  In addition to the present embodiment, the thermoplastic resin film includes a thermoplastic urethane-based elastomer layer that can be produced by a solution casting method, a melt extrusion method, a calendar method, and the like, and a modified ethylene-vinyl alcohol copolymer. A layer made of a multilayer film including one or more layers can be used.

<Second Embodiment>
8 and 9 show a run flat tire 1D as a pneumatic tire according to the second embodiment of the present invention. Here, FIG. 8 is a perspective view of the run-flat tire 1D, and FIG. 9A is a view showing a plurality of protrusions 20 of the turbulent flow generating portion provided in the sidewall portion 3, and FIG. 9B. Is a diagram showing the shape of the end of the protrusion in the tire radial direction inner side (tire rotation axis side), FIG. 9C is a cross-sectional view taken along the line AA in FIG. 9A, FIG. It is a side view of run flat tire 1D. In the run flat tire 1D of the present embodiment, the same portions as those of the above-described run flat tire 1 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

(Run flat tire)
The schematic configuration of the run-flat tire 1D is almost the same as that of the first embodiment described above, and includes a tread portion 2, a sidewall portion 3, and a bead portion 4.

  In this run flat tire 1 </ b> D, the entire outer surface of the sidewall portion 3 is a turbulent flow generating portion 5. That is, one turbulent flow generating portion 5 is provided over the entire sidewall portion, and a plurality of protrusions extending along the tire radial direction r are formed on the outer surface of the sidewall portion 3. A portion (projection) 20 is provided. These protrusions 20 have the same height along the tire radial direction r, and the pitch (p) between adjacent protrusions 20 is constant.

(Turbulent flow generator)
As shown in FIGS. 9A to 9C, the protruding portion 20 is formed with an upstanding surface 22 rising from the outer surface of the sidewall portion 3 at the end portion 21 on the inner side in the tire radial direction. Further, the protrusion 20 has an upper width (w2) smaller than a lower width (w1), and has a trapezoidal cross section. Therefore, the side surface of the protrusion 20 in the tire circumferential direction is an inclined surface that is inclined inwardly in the tire circumferential direction of the protrusion from the lower part to the upper part of the protrusion 20. A portion where the above-described standing surface 22 and the upper surface 24 of the protrusion 20 intersect becomes the top 23. Note that the width (w) when the width of the protrusion 20 is different between the upper portion and the lower portion as in the present embodiment refers to the width (w1) of the lower portion that is the widest width of the protrusion 20.

  And the turbulent flow generation | occurrence | production part 5 of this embodiment is the same as 1st Embodiment, and the height (h), pitch (p), and width (w) of the protrusion 20 are 1.0 <= p / h <=. The relationship of 50.0 and 1.0 ≦ (p−w) /w≦100.0 is satisfied. In addition to this embodiment, the ratio (p / h) between the pitch (p) and the height (h) of the protrusions is preferably 2.0 ≦ p / h ≦ 24.0, more preferably 10. If 0 ≦ p / h ≦ 20.0, the heat transfer coefficient of the sidewall portion surface can be further improved.

  In the present embodiment, the plurality of protrusions 20 are arranged at a predetermined pitch on the sidewall portion 3 where deterioration is likely to occur compared to other portions, so that the side turbulence of the air generated at the protrusions 20 Heat dissipation of the wall portion 3 can be promoted. This is because the rubber constituting the tire is a material with poor thermal conductivity, so rather than expanding the heat dissipation area and promoting heat dissipation, it promotes the generation of turbulent flow and directs the turbulent air flow directly to the sidewall part. It is thought that this is because the heat radiation effect by applying is great.

  And, in particular, the side wall portion compared to other parts in long-term use, such as a heavy load tire, a run flat tire having a side wall portion 3 provided with a crescent-shaped reinforcing rubber, and a TBR (truck bus radial) In the pneumatic tire provided with a portion in which a failure is likely to occur in 3, the effect of reducing the temperature of the sidewall portion 3 is enhanced.

  Note that the air flow (turbulent flow) defined by p / h as described above has a fine pitch (p), that is, if the pitch (p) is narrowed, the air flow does not enter and the pitch (p ) Is excessively wide, it is equivalent to the case where the protrusion 20 is not formed. Therefore, it is preferable that p / h be in the above numerical range.

  Moreover, (pw) / w shows the ratio of the protrusion 20 with respect to the pitch (p), and when this is too small, it is with respect to the area of the surface which wants to improve heat dissipation (outside surface of a side wall part). It is the same as that the ratio of the surface area of the protrusion 20 becomes equal. The protrusion 20 is made of rubber, and since a heat dissipation improvement effect due to an increase in surface area cannot be expected, the minimum value of (p−w) / w is defined as 1.0.

  Further, the extending direction of the protrusion 20 (see FIG. 7) preferably forms an angle θ (−70 ° ≦ θ ≦ 70 °) with respect to the tire radial direction. Since the run flat tire 1D is a rotating body, the air flow on the surface of the sidewall portion 3 is slightly outward in the radial direction due to centrifugal force. Therefore, in order to reduce the stagnation portion on the back side with respect to the inflow of air into the protrusion 20 and improve the heat dissipation, it is preferable to incline within the above angle range with respect to the radial direction r.

  In addition, the protrusion 20 may be configured to be discontinuously divided along the extending direction a. Moreover, the structure by which the protrusion 20 was arrange | positioned unevenly along the tire circumferential direction may be sufficient. Incidentally, when the protrusion 20 is provided on the outer surface of the sidewall portion 3, stagnation occurs on the back side of the protrusion with respect to the inflow of air, and heat dissipation is worse compared to the case where the protrusion 20 is not provided. A part will occur. In order to reduce the portion where the heat dissipation deteriorates and improve the average heat transfer coefficient, it is effective that the turbulent flow generating portion is divided discontinuously in the extending direction.

  In the turbulent flow generation unit 5, as in the first embodiment, with the rotation of the run flat tire 1D, the flow of air that is in contact with the sidewall portion 3 where the turbulent flow generation unit 5 is not formed is a protrusion. At 20, it is peeled off from the sidewall portion 3 and gets over the protrusion 20. At this time, an area where the air flow stays is formed on the back side of the protrusion 20. Then, the air flow reattaches to the bottom between the next protrusion 20 and is peeled off again at the next protrusion 20. At this time, a region where the air flow stays is generated between the air flow and the front surface of the next protrusion 20. Therefore, it is considered that the heat dissipation rate increases as the flow velocity of air on the region where the air flow stays increases.

  Moreover, since the run flat tire 1D of this embodiment has the top part 23 in the tire radial direction inner side end part 21 of the protrusion 20, the air flow peeled off from the top part 23 flows in the direction of centrifugal force while turning. it is conceivable that. Thereby, a heat dissipation rate can be raised more. In addition to this embodiment, the top portion 23 is arranged on the inner side in the tire radial direction from the portion where the temperature is most desired to be reduced, that is, the inclined surface is on the inner portion in the tire radial direction from the portion where the temperature is most desired to be reduced By providing, heat dissipation can be selectively enhanced. Further, in addition to the present embodiment, by forming the protrusion 20 along the tire radial direction, a plurality of top portions 23 are arranged along the tire radial direction, and the air flow starting from the top portion 23 is arranged. It is also possible to expand the region where heat dissipation is improved by the swirling flow.

  In addition, in this embodiment, although the several protrusion 20 was arrange | positioned at equal intervals, the turbulent flow generation part where the several protrusion 20 gathered is arrange | positioned intermittently along a tire circumferential direction besides this embodiment. It is good also as composition to do.

(Inner liner)
The inner liner 14 similar to that of the first embodiment can be used for the inner liner of the present embodiment.

<First Modification of Projection>
FIG. 10 shows a first modification of the protrusion that can be applied to the run-flat tires 1 and 1D of the first and second embodiments described above. In the following description of the modified examples, the same parts as those of the run flat tires 1 and 1D of the first and second embodiments described above are denoted by the same reference numerals, and similar parts are denoted by similar reference numerals. To do.

  The protrusion 12A of the turbulent flow generation part 5A is formed so that the width of the protrusion 12A gradually decreases along the tire radial direction r. In the first modification, the space between the protrusions 12A can be widened at the portion of the sidewall portion 3 that requires heat dissipation, and the heat dissipation efficiency can be increased. That is, the heat dissipation efficiency can be optimized by changing the interval between the protrusions 12A according to the position in the tire radial direction r. Note that the ratio (p / h) of the pitch (p) to the height (h) is 1.0 ≦ p / h ≦ 50.0 and 1.0 ≦ (p−w) in the modified example described below. ) /W≦100.0, and preferably 2.0 ≦ p / h ≦ 24.0.

<Second Modification of Projection>
FIG. 11 shows a second modification of the protrusion. As shown in FIG. 11, the turbulent flow generation projection 5B has a substantially right triangle in cross section cut in the tire circumferential direction in the tire circumferential direction, and a slope on the rear side of the projection with respect to the air flow S1. The cross section of the protrusion 12B has a downwardly convex curve, and the cross section cut in the tire circumferential direction is substantially rectangular, and the cross section of the slope on the back side of the protrusion protrudes upward with respect to the air flow S1. The protrusions 12 </ b> C that are curved lines are alternately formed.

  In the turbulent flow generation part 5B having the protrusions 12B and 12C of the second modification, as shown in FIG. 11, a region S2 in which the air flow stays is formed on the concave slope on the back side of the protrusion 12B. Therefore, it is possible to reduce the influence of air retention on the surface to be radiated between the protrusions 12B and 12C.

<Third Modification of Projection>
FIG. 12 shows a third modification. The turbulent flow generation part 5C having the protrusions of the third modification is substantially rectangular when viewed in cross section, and the cross section of the slope on the back face side of the protrusion is a convex curve with respect to the air flow S1. A plurality of protrusions 12D.

  In the third modified example, the air flow S1 that has passed over the protrusion 12D enters between the protrusions 12D along the back slope of the protrusion 12D, and therefore the portion S2 where the air flow stays is reduced. be able to. For this reason, it is possible to enhance the heat dissipation effect in the turbulent flow generation unit 5C.

<Fourth Modification of Projection>
FIG. 13 shows a fourth modification. The turbulent flow generating portion 5D having the protrusions of the fourth modification has a protrusion 12F having a substantially rectangular cross section in the tire rotation direction, and a height (h2) slightly lower than the height (h1) of the protrusion 12F. The protrusions 12G are alternately arranged. A groove 13D formed along the tire radial direction r is formed on the upper surface of the protrusion 12F, and a groove 13E formed along the tire radial direction r is formed on the upper surface of the protrusion 12G. In the protrusions 12F and 12G of the fifth modification, a more complicated turbulent flow is generated by the grooves 13D and 13E.

<Fifth Modification of Projection>
FIG. 14 shows a fifth modification. In the turbulent flow generation part 5F having the protrusions of the fifth modified example, the protrusions 12H having a high height and the protrusions 12I having a height lower than the protrusion 12H are alternately arranged. Thus, since the heights of the protrusions 12H and the protrusions 12I are different, turbulent flow is generated and heat dissipation efficiency is increased.

<Sixth Modification of Projection>
FIG. 15 shows a sixth modification. The turbulent flow generation part 5G having the protrusions of the sixth modification is formed by alternately arranging protrusions 12J and 12K having the same height and different width dimensions.

<Seventh Modification of Projection>
FIG. 16 shows a seventh modification. In the turbulent flow generation part 5H having the protrusions of the seventh modification, a plurality of protrusions 12M smaller than the protrusions 12L are arranged between the protrusions 12L having a rectangular cross section.

<Other variations>
Hereinafter, other modified examples of the turbulent flow generation unit will be described. In addition, in the modified example demonstrated below, the code | symbol 5 is attached | subjected to a turbulent flow generation part, and the code | symbol 12 is attached | subjected and demonstrated. Moreover, although the turbulent flow generation part 5 was intermittently arrange | positioned along the tire circumferential direction in the following modifications, you may form the turbulent flow generation part 5 continuously over the perimeter.

  The turbulent flow generator 5 shown in FIGS. 17 to 19 has a length equal to a length obtained by dividing 90% of the tire cross-section height (SH) from the baseline of the rim into three equal parts in the tire radial direction r. The protrusion 12 having the length or the protrusion 12 having a length equal to half or less than half of the SH is arranged by being shifted in the rotation direction.

  The turbulent flow generating section 5 shown in FIG. 20 is separated from each other in the tire rotation direction so that a part of the protrusion overlaps in the vicinity of the center of the sidewall section 3 when the turbulent flow generating section 5 is viewed from the circumferential direction. The arranged protrusions 12 are arranged.

  The turbulent flow generating portion 5 shown in FIG. 21 is arranged by inclining the outer protrusion 12 and the inner protrusion 12 in the tire radial direction with respect to the tire radial direction so as to extend in alternate directions. It becomes.

  22 has a structure in which a plurality of protrusions 12 extending in an oblique direction with respect to the tire radial direction r are arranged in parallel.

  The turbulent flow generation section 5 shown in FIGS. 23 and 24 is configured by arranging a plurality of groups of protrusions 12 having different angles with respect to the tire radial direction.

  The turbulent flow generation part 5 shown in FIG. 25 has a protrusion 12 aligned in the tire radial direction and a protrusion 12 arranged in an oblique direction with respect to the tire radial direction.

  The turbulent flow generation section 5 shown in FIG. 26 has a plurality of protrusions 12 that are curved in a substantially “<” shape along the tire radial direction.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

(Conventional example)
Using a 2 mm rubber sheet for the inner liner, p / h is 12, (p−w) / w is 23, θ is 0, and a tire having the same configuration as that of the first embodiment is manufactured and is durable under the following conditions. A drum test was performed.

(Comparative Example 1)
A tire without a turbulent flow generation part using a 2 mm rubber sheet for the inner liner was prepared, and a durability drum test was performed under the following conditions.

(Comparative Example 2)
A tire without a turbulent flow generation part using a 2 mm thermoplastic film sheet for the inner liner was prepared, and a durability drum test was performed under the following conditions.

(Examples 1-2)
A laminate of 1 mm rubber sheet and 1 mm thermoplastic film sheet or 2 mm thermoplastic film sheet was used for the inner liner, p / h was 12, (p−w) / w was 23, and θ was 0. A tire having the same configuration as that of the first embodiment was manufactured, and a durability drum test was performed under the following conditions.

(Drum durability test)
Tire size: 285 / 50R20
Rim used: 8JJ × 20
Internal pressure: 0 kpa
Load: 9.8kN
Speed: 90km / h
The drum durability test (JIS K6302) was performed under the above conditions, and the durability distance until the failure occurred was indexed with the conventional example as 100. The results are shown in Table 1.

* 1 As the thermoplastic film, a film produced as follows (film 1 described in JP-A-2008-024217) was used.

(Synthesis of modified ethylene-vinyl alcohol copolymer (B))
In a pressurized reaction vessel, ethylene-vinyl alcohol copolymer (A) having an ethylene content of 44 mol% and a saponification degree of 99.9% (190 ° C., MFR under 2160 g load: 5.5 g / 10 min) 2 masses And 8 parts by mass of N-methyl-2-pyrrolidone were heated and stirred at 120 ° C. for 2 hours to completely dissolve the ethylene-vinyl alcohol copolymer (A). To this was added 0.4 part by mass of epoxypropane as an epoxy compound (E), and then heated at 160 ° C. for 4 hours. After the heating, it is precipitated in 100 parts by mass of distilled water, and N-methyl-2-pyrrolidone and unreacted epoxypropane are sufficiently washed with a large amount of distilled water to obtain a modified ethylene-vinyl alcohol copolymer (B). It was. Further, the modified ethylene-vinyl alcohol copolymer (B) thus obtained was fined to a particle size of about 2 mm with a pulverizer, and then sufficiently washed with a large amount of distilled water again. The washed particles were vacuum-dried at room temperature for 8 hours, and then melted at 200 ° C. using a twin-screw extruder to be pelletized. The Young's modulus at 23 ° C. of the resulting modified ethylene-vinyl alcohol copolymer (B) was measured using a Shimadzu Corporation autograph [AG-A500 type] with a chuck interval of 50 mm and a tensile speed of 50 mm / min. It was 1300 MPa when measured under the conditions.

(Synthesis of flexible resin (C))
A maleic anhydride-modified hydrogenated styrene-ethylene-butadiene-styrene block copolymer was synthesized by a known method and pelletized. The resulting maleic anhydride-modified hydrogenated styrene-ethylene-butadiene-styrene block copolymer had a Young's modulus at 23 ° C. of 3 MPa, a styrene content of 20%, and a maleic anhydride amount of 0.3 meq / g. The Young's modulus at 23 ° C. was measured by the same method as that for the modified ethylene-vinyl alcohol copolymer (B).

(Preparation of film 1)
The modified ethylene-vinyl alcohol copolymer (B) and the flexible resin (C) are kneaded with a twin-screw extruder so that the blending amount is B: C = 80: 20, and the resin composition (D) Got. Here, the average particle diameter of the flexible resin (C) in the resin composition (D) is determined by freezing a sample of the obtained resin composition (D), and then slicing the sample with a microtome. Measured with Further, the Young's modulus at −20 ° C. of the resin composition (D) was measured in the same manner as the above Young's modulus measurement method except that the set temperature was changed to −20 ° C. Next, using the obtained resin composition (D) and thermoplastic polyurethane (TPU) [Kuraray Co., Ltd. Kuramylon 3190], using a two-kind three-layer coextrusion apparatus, the following coextrusion molding conditions A three-layer film 1 (thermoplastic polyurethane layer / resin composition (D) layer / thermoplastic polyurethane layer) was prepared. Here, the thickness of the layer of the film 1 is TPU layer: resin composition (D) layer: TPU layer = 1: 1: 1.
Extrusion temperature of each resin: C1 / C2 / C3 / die = 170/170/200/200 ° C.
Extruder specifications for each resin:
Thermoplastic polyurethane: 25mmφ extruder P25-18AC [Osaka Seiki Machine Co., Ltd.]
Resin composition (D) or modified EVOH (B): 20 mmφ extruder laboratory machine ME type CO-EXT [manufactured by Toyo Seiki Co., Ltd.]
T-die specification: 500mm width, 2 types, 3 layers [Plastic Engineering Laboratory Co., Ltd.]
Cooling roll temperature: 50 ° C
Pickup speed: 4m / min

The physical properties of the obtained film 1 are as follows: Young's modulus at −20 ° C .: 750 MPa, average particle diameter of the flexible resin (C): 1.2 μm, oxygen permeation amount of the resin composition (D) layer: 9.3 × 10 ⁻¹³ cm ³ · cm / cm ² · sec · cmHg, oxygen transmission rate of TPU layer: 4.6 × 10 ⁻¹¹ cm ³ · cm ² · sec · cmHg, oxygen transmission rate of film 1: 9 1 × 10 ⁻¹³ cm ³ · cm / cm ² · sec · cmHg.

  From Table 1, it has been clarified that the durability performance of the tire is dramatically improved by providing a turbulent flow generation protrusion on the sidewall portion and using a thermoplastic resin film for the inner liner.

It is a side view of the run flat tire of a 1st embodiment of the present invention. 1 is a perspective view showing a cross section of a main part of a run flat tire according to a first embodiment of the present invention. It is sectional drawing which shows the principal part cross section of the run flat tire of 1st Embodiment of this invention. It is a perspective view which shows the principal part of the turbulent flow generation part of the run flat tire of 1st Embodiment of this invention. It is a section explanatory view showing a turbulent flow generation state in a turbulent flow generation part of a run flat tire of a 1st embodiment of the present invention. It is a side view of the turbulent flow generation part of the run flat tire of a 1st embodiment of the present invention. It is explanatory drawing which shows the pitch p and angle (theta) of the turbulent flow generation part of the run flat tire of 1st Embodiment of this invention. It is a perspective view which shows the principal part cross section of the run flat tire of 2nd Embodiment of this invention. (A) is the run flat tire of 2nd Embodiment of this invention, (b) is the side view which looked at the tire radial direction inner side edge part of the protrusion from the tire rotating shaft side, (c) is FIG. 9 (a). Sectional drawing which follows the AA line, (d) is a side view of the run-flat tire of 2nd Embodiment of this invention. It is a principal part perspective view which shows the 1st modification of the protrusion of a run flat tire. It is a principal part perspective view which shows the 2nd modification of the protrusion of a run flat tire. It is a principal part perspective view which shows the 3rd modification of the protrusion of a run flat tire. It is a principal part perspective view which shows the 4th modification of the protrusion of a run flat tire. It is a principal part perspective view which shows the 5th modification of the protrusion of a run flat tire. It is a principal part perspective view which shows the 6th modification of the protrusion of a run flat tire. It is a principal part perspective view which shows the 7th modification of the protrusion of a run flat tire. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part. It is a side view of the run flat tire which shows the modification of a turbulent flow generation part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Run flat tire 2 Tread part 3 Side wall part 4 Bead part 5 Turbulence generating part 12 Protrusion part 14 Inner liner 20 Protrusion part 23 Top part

Claims (21)

A tread portion; a pair of bead portions; and a pair of sidewall portions extending between the tread portion and each bead portion, and each of these portions extending in a toroid shape between the pair of bead portions. In a pneumatic tire provided with a carcass that reinforces and an inner liner provided inside the carcass,
A turbulent flow generation part including a protrusion is provided on at least a part of the surface of the sidewall part,
A pneumatic tire characterized in that a thermoplastic resin film is used for the inner liner. The turbulent flow generation unit includes a plurality of protrusions,
When the height of the protrusions is h, the width is w, and the pitch between the protrusions in the turbulent flow generation part is p,
1.0 ≦ p / h ≦ 50.0 and 1.0 ≦ (p−w) /w≦100.0
The pneumatic tire according to claim 1, wherein the following relationship is satisfied.   The pneumatic tire according to claim 2, wherein a ratio (p / h) between the pitch (p) and the height (h) is 2.0 ≦ p / h ≦ 24.0.   The ratio (p / h) between the pitch (p) and the height (h) is 10.0 ≦ p / h ≦ 20.0, according to claim 2 or 3, Pneumatic tire.   The pneumatic tire according to claim 2, wherein the (p−w) / w is 4.0 ≦ (p−w) /w≦39.0. The height (h) of the protrusion is 0.5 mm ≦ h ≦ 7 mm,
The pneumatic tire according to claim 1, wherein a width (w) of the protrusion is 0.3 mm ≦ h ≦ 4 mm.   The pneumatic tire according to claim 1, wherein an angle θ formed by the extending direction of the protrusion with respect to the tire radial direction is −70 ° ≦ θ ≦ 70 °.   The pneumatic tire according to any one of claims 1 to 7, wherein an upper width of the protrusion is smaller than a width of a lower portion of the protrusion at least at a radially inner end portion of the tire.   The pneumatic tire according to claim 1, wherein an angle θ formed by the extending direction of the protrusion with respect to the tire radial direction varies depending on a position in the tire radial direction.   The pneumatic tire according to claim 1, wherein the protrusion is discontinuously divided along the extending direction.   The pneumatic tire according to claim 1, wherein the protrusions are non-uniformly arranged along a tire circumferential direction.   The pneumatic tire according to claim 1, wherein the sidewall portion includes a crescent-shaped reinforcing rubber.   The pneumatic tire according to claim 1, wherein the pneumatic tire is a heavy load tire.   The thermoplastic resin film has a Young's modulus at 23 ° C. in a matrix composed of a modified ethylene-vinyl alcohol copolymer (B) obtained by reacting the ethylene-vinyl alcohol copolymer (A) with the modified ethylene-vinyl. The air according to claim 1, comprising at least a layer made of a resin composition (D) obtained by dispersing a soft resin (C) smaller than the alcohol copolymer (B). Enter tire.   The pneumatic tire according to claim 14, wherein the flexible resin (C) has a Young's modulus at 23 ° C. of 500 MPa or less.   The pneumatic tire according to claim 14 or 15, wherein the flexible resin (C) has a functional group that reacts with a hydroxyl group.   The pneumatic tire according to any one of claims 14 to 16, wherein a content of the flexible resin (C) in the resin composition (D) is in a range of 10 to 80 mass%.   The pneumatic tire according to any one of claims 14 to 17, wherein the flexible resin (C) has an average particle size of 2 m or less.   The pneumatic tire according to any one of claims 14 to 18, wherein a layer made of the resin composition (D) is crosslinked. The layer made of the resin composition (D) has an oxygen permeation amount of 3.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less at 20 ° C. and 65% RH, The pneumatic tire according to any one of claims 14 to 19.   The pneumatic tire according to any one of claims 14 to 20, wherein the layer made of the resin composition (D) has a thickness of 100 µm or less.

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