JP2009279977A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire having an inner liner formed of a thermoplastic resin or a thermoplastic elastomer composition, configured to prevent a damage on the inner liner in mending a puncture. <P>SOLUTION: In this pneumatic tire, a thermoplastic resin film layer 11 formed of the thermoplastic resin or the thermoplastic elastomer composition made by blending elastomer in the thermoplastic resin is arranged in the internal surface of the tire, and a protective rubber layer 12 is laminated in the internal surface of the thermoplastic resin film layer 11. At least the thickness of one of the thermoplastic resin film layer 11 or the protective rubber layer 12 is varied. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a pneumatic tire, and more particularly, a pneumatic tire having an inner liner made of a thermoplastic resin or a thermoplastic elastomer composition, and more particularly a pneumatic tire for preventing damage to the inner liner. Related to pneumatic tires.

  In general, a tubeless pneumatic tire uses a butyl rubber having an excellent air permeation preventive property as compared with other rubber for an inner liner on the inner surface of the tire. However, since butyl rubber has a large specific gravity, it contributes to the weight of the tire. For this reason, as one of the methods for reducing the weight of the tire, the inner liner is lighter than butyl rubber and has a heat permeability made of a thermoplastic resin or a thermoplastic elastomer composition having a low air permeability of 1/3 to 1/10. There is a proposal to use a plastic resin film (for example, see Patent Document 1).

  However, since the thermoplastic resin or the thermoplastic elastomer composition has a remarkably large elastic modulus compared to rubber, the durability against bending cannot be maintained unless it is used as an extremely thin film. Even if it is made extremely thin in this way, the air permeation preventive property is superior to that of butyl rubber, so that it can sufficiently function as an air permeation preventive layer.

However, the inner liner made of a thermoplastic resin film has a high elastic modulus and is extremely thin, so it may be easily damaged when a tool touches the inner liner during rim assembly work, etc. The impact on performance is extremely large. In particular, when the tire is punctured by nailing or the like, the tread portion is easily damaged due to buffing the inner liner for puncture repair, and there is a problem in durability.
JP 08-258506 A

  An object of the present invention is to provide a pneumatic tire having an inner liner made of a thermoplastic resin or a thermoplastic elastomer composition, in which damage to the inner liner that is likely to occur during puncture repair is prevented. There is.

  The pneumatic tire of the present invention that achieves the above object is provided with a thermoplastic resin film layer formed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer in a thermoplastic resin on the inner surface of the tire, and the thermoplastic resin. A protective rubber layer is laminated on the inner surface of the film layer, and the thickness of at least one of the thermoplastic resin film layer or the protective rubber layer is changed.

  The thermoplastic resin film layer corresponds to the center region of the tread portion with a thickness of at least one region selected from a region corresponding to the buttress portion from the shoulder portion, a region corresponding to the sidewall portion, and a region corresponding to the bead portion. Make the thickness larger than the thickness of the part to be

  Further, in the case of a tire in which a main groove in the tire circumferential direction is arranged in the tread portion, the thickness of the region corresponding to the main groove of the protective rubber layer is made larger than the thickness of the portion corresponding to the tread portion other than the main groove. . The thickness of the region corresponding to the tread portion of the protective rubber layer is made larger than the thickness of the protective rubber layer in the other remaining regions.

  The thermoplastic resin film layer may have a thickness of 0.03 to 0.5 mm, and the protective rubber layer may have a thickness of 0.2 to 2.0 mm. The protective rubber layer may have a thickness corresponding to the tread portion of 0.5 mm or more. The region in which the protective rubber layer is thicker than the other protective rubber layers in the other regions is at least a region corresponding to the outermost main groove provided in the tread portion and in the tire width direction inner region, and in this range. The thickness of the protective rubber layer is preferably 0.5 to 2.0 mm. The protective rubber layer may be formed from butyl rubber.

  The pneumatic tire of the present invention has a protective rubber layer laminated on the inner surface of an inner liner composed of a thermoplastic resin film made of a thermoplastic resin or a thermoplastic elastomer composition, and at least a thermoplastic resin film layer or a protective rubber layer. Since the thickness of one side is changed, the inner surface of the tread portion can be buffed during puncture repair work or the like, and damage to the protective rubber layer can be prevented even if tools contact.

  FIG. 1 is a half sectional view in the tire meridian direction showing an example of an embodiment of a pneumatic tire of the present invention.

  In the heavy duty pneumatic tire shown in FIG. 1, 1 is a tread portion, 2 is a shoulder portion, 3 is a sidewall portion, 4 is a bead portion, 5 is a carcass layer, and 10 is a buttress portion. The carcass layer 5 is mounted between a pair of left and right bead cores 6 embedded in the bead portion 4, and both end portions thereof are folded around the bead core 6 from the tire inner side to the outer side. In the tread portion 1, four belt layers 7 are arranged on the outer side of the carcass layer 5 over the circumference of the tire. In the tread portion 1, a tread rubber is disposed outside the belt layer 7, and three main grooves 9 are formed to extend in the tire circumferential direction over the entire width of the tire. An inner liner 11 for preventing air permeation is attached inside the carcass layer 5, and a protective rubber layer 12 is laminated on the inner side. The inner liner 11 is composed of an extremely thin thermoplastic resin film layer formed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer in a thermoplastic resin. The thickness of the thermoplastic resin film layer is preferably 0.03 to 0.5 mm, more preferably 0.075 to 0.30 mm, whereas the thickness of the protective rubber layer is preferably 0.2 to 2. 0.0 mm, more preferably 0.5 to 1.5 mm. As described above, the protective rubber layer 12 is laminated on the inner side of the inner liner 11 to prevent damage to the ultrathin thermoplastic resin film layer.

  In the pneumatic tire of the present invention, the thickness of at least one of the thermoplastic resin film layer or the protective rubber layer is changed. The thickness of the protective rubber layer 12 corresponding to the tread portion 1 is preferably 0.5 mm or more, more preferably 1.0 to 1.5 mm, and the thickness of the protective rubber layer 12 in other remaining regions. Also thicken. By making the thickness of the protective rubber layer 12 0.5 mm or more and thicker than the protective rubber layers in other remaining areas, even when the inner surface of the tire is buffed in the puncture repair work, the inner liner is not damaged. can do. Moreover, the increase in tire weight can be suppressed by increasing the thickness of the tread portion 1 of the protective rubber layer 12 and decreasing the thickness of other portions. The region where the protective rubber layer 12 is thickened may be at least in the range in the tire width direction from the position corresponding to the outermost main groove provided in the tread portion. The other part is a part excluding the tread part 1 and refers to each region corresponding to the buttress part 10, the sidewall part 3, and the bead part 4. The method for partially increasing the thickness of the protective rubber layer is not particularly limited, and a plurality of protective rubber layers may be laminated, or extrusion may be performed so as to partially increase the thickness.

  The thermoplastic resin film layer made of a thermoplastic resin or a thermoplastic elastomer composition provided as an inner liner in the pneumatic tire of the present invention may have a substantially uniform thickness in the entire region, but in a region where air leakage is likely to occur. Accordingly, the tire meridian direction cross section may be changed. Thus, by adjusting the thickness according to the region where air leakage is likely to occur, it is possible to suppress the oxidative deterioration of the peripheral rubber member due to air leakage, and to improve tire durability.

  As described above, the region where the thickness of the thermoplastic resin film layer is changed to increase the thickness is from the shoulder portion 2 to the buttress portion 10, the sidewall portion 3, the bead portion 4 and the main groove 9 of the tread portion 1. At least one selected from the corresponding region may be used. Since the rubber member is thin under the main groove 9 in the sidewall portion 3 and the tread portion 1, the air permeation amount tends to increase. Further, in the region from the shoulder portion 2 to the buttress portion 10 and the bead portion 4, if air leakage occurs, the tire durability of the constituent members is likely to decrease due to oxidative degradation of the surrounding rubber members. Therefore, by increasing the thickness of the thermoplastic resin film layer in these regions, the air permeation preventive property can be improved, and the durability can be improved by suppressing the oxidative deterioration of the rubber member. The method for partially increasing the thickness of the thermoplastic resin film layer is not particularly limited, and for example, a method of laminating and forming a plurality of thermoplastic resin film layers can be preferably exemplified.

  Moreover, in this specification, the thickness of the part corresponding to the center area | region of the tread part of a thermoplastic resin film layer means the thickness of the part corresponding to tread parts other than a main groove. This is because the center region of the tread portion other than the main groove has a larger thickness of the entire rubber member including the tread rubber, the coat rubber of the belt layer, and the like, and therefore has better air permeation prevention than the other regions.

  When the thickness in the region where the thermoplastic resin film layer is thick is Ga and the thickness of the portion corresponding to the center region of the tread portion is Gb, the ratio Ga / Gb between the two is preferably 1.05. It should be 1.30, more preferably 1.10 to 1.25. If the thickness ratio Ga / Gb is smaller than 1.05, the air permeation preventing property cannot be sufficiently improved, and the effect of preventing the oxidative deterioration and improving the durability cannot be sufficiently obtained. If the ratio Ga / Gb is greater than 1.30, the tire weight increases. The thickness Ga is the maximum thickness in the thick region, and the thickness Gb is the maximum thickness of the portion corresponding to the tread portion other than the main groove 9.

  FIG. 2 is a tire half-sectional view showing an example of another embodiment of the present invention in which the thickness of the thermoplastic resin film layer is changed.

  In FIG. 2, the thickness of the region w1 corresponding to the buttress portion 10 from the shoulder portion 2 of the inner liner 11 constituted by the thermoplastic resin film layer is larger than the thickness of the portion w0 corresponding to the center region of the tread portion. To. The region w1 is perpendicular to the inner liner from the end 7e of the belt layer 7 having the maximum width, and is within the range of 5 to 10% of the inner peripheral along the inner side of the tire meridian cross section around the intersection. There should be. If the width of the region w1 is less than 5% of the inner periphery, the effect of improving the tire durability by preventing the air permeation prevention and preventing the oxidative deterioration cannot be obtained. If it exceeds 10%, the tire weight increases. In the present specification, the inner periphery is a length along the tire inner peripheral surface from one bead toe to the other bead toe in the tire meridian direction cross section.

  The thickening of the thermoplastic resin film layer from the shoulder portion to the buttress portion in this way is particularly effective for pneumatic tires having an air pressure of 450 kPa or more, and can be applied to heavy load tires such as trucks and buses. preferable.

  FIG. 3 is a tire half-sectional view showing another example of another embodiment of the present invention in which the thickness of the thermoplastic resin film layer is also changed.

  In FIG. 3, the thickness of the region w2 corresponding to the sidewall portion of the inner liner 11 formed of the thermoplastic resin film layer is set to be larger than the thickness of the portion w0 corresponding to the center region of the tread portion. The region w2 is preferably drawn within a range of 3 to 8% of the inner peripheral along the inner side of the tire meridian cross section with a perpendicular line drawn from the point P of the maximum width of the carcass line to the inner liner and centering on the intersection. If the width of the region w2 is less than 3% of the inner periphery, the effect of improving the air permeation prevention property cannot be sufficiently obtained. Further, if it exceeds 8%, the tire weight increases.

  The thickening of the thermoplastic resin film layer in the sidewall portion in this way is particularly preferably applied to a passenger car pneumatic tire.

  FIG. 4 is a tire half cross-sectional view showing still another example of another embodiment of the present invention in which the thickness of the protective rubber layer is changed.

  In FIG. 4, the thickness of the region w <b> 3 corresponding to the main groove 9 of the tread portion 1 of the protective rubber layer 12 is made larger than the thickness of the region w <b> 0 corresponding to the tread portion 1 other than the main groove 9. At this time, the protective rubber layer 12 may be composed of butyl rubber. The width of the region w3 may be wider than the opening width of the main groove 9, and more preferably 0.01 to 3.0 mm wider than the opening width. If the width of the region w3 is less than the main groove opening width, the portion of the main groove under the groove cannot be sufficiently covered, and the effect of improving the air permeation prevention becomes insufficient. Moreover, if the width exceeds 3.0 mm beyond the opening width, the tire weight increases. The main groove opening width is the distance in the tire width direction between both side edges of the main groove opening on the tread surface. When the edge of the main groove is chamfered, each of the groove walls on both sides of the main groove The distance in the tire width direction between the intersections of the extension line and the extension line of the tread surface.

  FIG. 5 is a tire half sectional view showing still another example of another embodiment of the present invention in which the thickness of the thermoplastic resin film layer is changed.

  In FIG. 5, the heavy duty pneumatic tire has a chafer 8 disposed in the bead portion 4, and the thickness of the region w <b> 4 corresponding to the bead portion of the inner liner 11 composed of the thermoplastic resin film layer is tread. The thickness is made larger than the thickness of the portion w0 corresponding to the center region of the portion. In the bead portion of the heavy-duty pneumatic tire, air leaks through the carcass layer 5 and the surrounding rubber members are susceptible to oxidative degradation. Since it is easy to deteriorate, it causes troubles such as chafer separation. For this reason, by increasing the thickness of the thermoplastic resin film layer in the region w4, the deterioration of air permeation is prevented, thereby preventing oxidative degradation and improving the durability.

  The region w4 corresponding to the bead portion is perpendicular to the inner liner from the winding terminal 5e of the carcass layer. Good. If the region w4 is less than 3% of the inner periphery, the effect of preventing oxidative degradation and improving durability cannot be obtained sufficiently. If it exceeds 10%, the tire weight increases.

In the present invention, the protective rubber layer can be any rubber as long as it is used for pneumatic tires. A diene rubber is preferable. Examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR, high cis BR and low cis BR), and nitrile rubber (NBR). ), Butyl rubber (IIR), and halogenated butyl rubber. Of these, butyl rubbers such as butyl rubber and halogenated butyl rubber are preferable. The air permeability coefficient of butyl rubber is 4.5 to 5.5 × 10 ⁻⁹ cc · cm / cm ² · sec · cmHg, and the air permeability coefficient is smaller than that of general rubber used for tread rubber. The air permeation prevention performance can be further improved by laminating the inner liner.

In the present invention, the thermoplastic resin or the thermoplastic elastomer composition forming the thermoplastic resin film layer has an air permeability coefficient of 15 to 30 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg, tread rubber, etc. The air permeability coefficient is remarkably minimum as compared with the general rubber used in the above.

  Moreover, the Young's modulus of the thermoplastic resin or the thermoplastic elastomer composition is not particularly limited, and is preferably 1 to 500 MPa, more preferably 50 to 500 MPa.

  Examples of the thermoplastic resin include polyamide-based resins [for example, nylon 6 (N6), nylon 66 (N66), nylon 46 (N46), nylon 11 (N11), nylon 12 (N12), nylon 610 (N610), Nylon 612 (N612), nylon 6/66 copolymer (N6 / 66), nylon 6/66/610 copolymer (N6 / 66/610), nylon MXD6 (MXD6), nylon 6T, nylon 6 / 6T Polymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer) and their N-alkoxyalkylated products, for example, methoxymethylated product of nylon 6, methoxymethylated product of nylon 6/610 copolymer, nylon 612 methoxymethylated product, polyester resin [for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, polyoxyalkylene diimide diacid / poly Aromatic polyesters such as butylene terephthalate copolymer], polynitrile resins (for example, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), (meth) acrylonitrile / styrene copolymer, ( (Meth) acrylonitrile / styrene / butadiene copolymer], polymethacrylate resin [for example, polymethyl methacrylate (PMMA), polyethyl methacrylate], polyvinyl resin [for example, vinyl acetate, polyvinyl Lucol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PDVC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer, vinylidene chloride / Acrylonitrile copolymer (ETFE)], cellulose resin [eg, cellulose acetate, cellulose acetate butyrate], fluorine resin [eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE) ), Tetrafluoroethylene / ethylene copolymer], imide resin [for example, aromatic polyimide (PI)] and the like can be preferably used.

  The thermoplastic elastomer composition used in the present invention can be constituted by blending the above-described thermoplastic resin and elastomer.

  Examples of the elastomer constituting the thermoplastic elastomer composition include diene rubbers and hydrogenated products thereof [eg, natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene butadiene rubber (SBR), butadiene] Rubber (BR, high cis BR and low cis BR), nitrile rubber (NBR), hydrogenated NBR, hydrogenated SBR], olefin rubber [for example, ethylene propylene rubber (EPDM, EPM), maleic acid modified ethylene propylene rubber ( M-EPM), butyl rubber (IIR), isobutylene and aromatic vinyl or diene monomer copolymer, acrylic rubber (ACM), ionomer], halogen-containing rubber [eg, Br-IIR, CI-IIR, isobutylene paramethylstyrene Copolymer bromide (Br-IPMS), black Plain rubber (CR), hydrin rubber (CHR), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM), maleic acid modified chlorinated polyethylene rubber (M-CM)], silicone rubber [eg methyl vinyl silicone rubber , Dimethyl silicone rubber, methyl phenyl vinyl silicone rubber], sulfur-containing rubber (for example, polysulfide rubber), fluorine rubber (for example, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicon) Rubber, fluorine-containing phosphazene rubber), thermoplastic elastomer (for example, styrene elastomer, olefin elastomer, ester elastomer, urethane elastomer, polyamido elastomer) and the like are preferable. It is possible to use.

  In the thermoplastic elastomer composition, the composition ratio between the specific thermoplastic resin and the elastomer is not particularly limited, and is appropriately determined so as to have a structure in which the elastomer is dispersed as a discontinuous phase in the thermoplastic resin matrix. The preferred range is 90/10 to 30/70 by weight. The thermoplastic elastomer composition can have sufficient flexibility and rigidity in the inner liner by adopting a form in which the thermoplastic resin forms a continuous phase (matrix) and the elastomer becomes a dispersed phase (domain). At the same time, molding processability equivalent to that of a thermoplastic resin can be obtained during molding regardless of the amount of elastomer.

  When the above-mentioned specific thermoplastic resin and elastomer are different in compatibility, they can be made compatible by using an appropriate compatibilizing agent as the third component. As a compatibilizing agent, a thermoplastic resin and an elastomer, a copolymer having one or both structures, or an epoxy group, a carbonyl group, a halogen group, an amino group, an oxazoline group, a hydroxyl group, etc. that can react with the thermoplastic resin or elastomer The structure of a copolymer having These may be selected depending on the types of thermoplastic resin and elastomer to be mixed. Although there are no particular limitations on the amount of such a compatibilizer, it is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymer component (the total of the thermoplastic resin and the elastomer).

  In the present invention, a thermoplastic resin or a thermoplastic elastomer composition generally includes a filler (calcium carbonate, titanium oxide, alumina, etc.), a reinforcing agent such as carbon black and white carbon, a softener, a plasticizer, etc. Agents, processing aids, pigments, dyes, anti-aging agents, and the like can be optionally added as long as the necessary properties as the inner liner are not impaired.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, the scope of the present invention is not limited to these Examples.

1 is a pneumatic tire having a tire size of 275 / 80R22.5, in which an inner liner is composed of a thermoplastic resin film layer, and when a protective rubber layer is laminated on the inner liner, Nylon 6/66 copolymer (N6 / 66) and a thermoplastic elastomer composition obtained by blending a brominated product of isobutylene paramethylstyrene copolymer (Br-IPMS) (the air permeability coefficient is 0.98 × 10 ⁻¹² cc) · ^cm / cm was formed by 2 · sec · cmHg), a common condition to form a protective rubber layer in butyl rubber (air permeability coefficient ratio ^{5.5 × 10 -12 cc · cm /} cm 2 · sec · cmHg) The tread portion of the protective rubber layer and the thickness of the portion corresponding to the other remaining region and the tread portion other than the main groove of the thermoplastic resin film layer (the main groove 10 types of pneumatic tires by changing the thickness of the region corresponding to the center region of the outer tread portion), the main groove region, the shoulder portion, the buttress portion, the sidewall portion, and the bead portion as shown in Table 1. (Examples 1-7, Comparative Examples 1-3) were produced.

  The obtained 10 types of pneumatic tires (Examples 1 to 7 and Comparative Examples 1 to 3) were measured for tire weight, and their reciprocals were shown as an index with the tire of Comparative Example 1 as 100 and are shown in Table 1. A larger index means a lighter tire. Moreover, the air permeation prevention performance, tire durability, and bead durability of each pneumatic tire were measured by the following test methods, respectively. In Comparative Example 2, the thickness of the protective rubber layer in the tread portion is small and it is difficult to buff the puncture repair work.

Air permeation prevention performance The obtained tire is mounted on a rim (22.5 × 7.50), and the internal pressure is measured every 4 days while it is left to stand for 3 months under an initial pressure of 900 kPa, room temperature of 21 ° C. and no load. did. As the initial pressure P0 (kPa), the measured pressure Pt (kPa), and the elapsed time t (day), the regression coefficient α was calculated by the following equation (1).
Pt / P0 = exp (−αt) (1)
From the obtained regression coefficient α, t = 30 (days), and the pressure decrease rate β (% / month) per month was calculated by the following formula (2).
β = (1-exp (−αt)) × 100 (2)
The obtained β value was an index with the value of Comparative Example 1 as 100, and the air permeation preventing performance is shown in Table 1. The smaller this index is, the better the air permeation preventing performance is.

Tire durability The obtained tire was mounted on a rim (22.5 × 7.50), applied to an indoor drum tester (drum diameter 1707 mm) in accordance with JIS D4230, and filled with air prepared to an oxygen concentration of 60%. The running distance until a tire failure occurred was measured under the condition of a JATMA specified air pressure of 900 kPa, 150% of the JATMA specified load capacity, and a speed of 81 km / h. The obtained travel distance is shown in Table 1 as an index with the value of Comparative Example 1 as 100. The larger this index, the better the tire durability.

Bead durability After the tire durability test described above, the pneumatic tire in which the failure occurred was disassembled and the number of occurrences of chafer separation in the bead portion was visually evaluated. The obtained results are shown in Table 1 as an index with the reciprocal of the result of Comparative Example 1 as 100. The larger this index, the better the bead durability.

1 is a tire meridian half-sectional view illustrating an embodiment of a pneumatic tire of the present invention. It is a tire meridian direction half sectional view which illustrates other embodiments of the pneumatic tire of the present invention. It is a tire meridian direction half sectional view which illustrates other embodiments of the pneumatic tire of the present invention. It is a tire meridian direction half sectional view which illustrates other embodiments of the pneumatic tire of the present invention. It is a tire meridian direction half sectional view which illustrates other embodiments of the pneumatic tire of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Shoulder part 3 Side wall part 4 Bead part 9 Main groove 10 Buttress part 11 Inner liner 12 Protective rubber layer

Claims (10)

  A thermoplastic resin film layer formed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer in a thermoplastic resin is provided on the tire inner surface, and a protective rubber layer is laminated on the inner surface of the thermoplastic resin film layer, A pneumatic tire in which the thickness of at least one of the thermoplastic resin film layer or the protective rubber layer is changed.   The pneumatic tire according to claim 1, wherein a thickness of a region corresponding to the buttress portion from the shoulder portion of the thermoplastic resin film layer is larger than a thickness of a portion corresponding to the center region of the tread portion.   The pneumatic tire according to claim 1 or 2, wherein a thickness of a region corresponding to the sidewall portion of the thermoplastic resin film layer is larger than a thickness of a portion corresponding to a center region of the tread portion.   A tire in which a main groove in the tire circumferential direction is arranged in the tread portion, and a thickness of a region corresponding to the main groove of the protective rubber layer is made larger than a thickness of a portion corresponding to the tread portion other than the main groove The pneumatic tire according to claim 1, 2 or 3.   The pneumatic tire according to any one of claims 1 to 4, wherein a thickness of a region corresponding to the bead portion of the thermoplastic resin film layer is larger than a thickness of a portion corresponding to the center region of the tread portion.   The pneumatic tire according to any one of claims 1 to 5, wherein a thickness of a region corresponding to the tread portion of the protective rubber layer is larger than a thickness of the protective rubber layer in other remaining regions.   The pneumatic resin according to any one of claims 1 to 6, wherein the thermoplastic resin film layer has a thickness of 0.03 to 0.5 mm, and the protective rubber layer has a thickness of 0.2 to 2.0 mm. tire.   The pneumatic tire according to any one of claims 1 to 7, wherein a thickness of a portion corresponding to the tread portion of the protective rubber layer is 0.5 mm or more.   The region in which the protective rubber layer is thicker than the other protective rubber layers in the remaining region is at least a range corresponding to the outermost main groove provided in the tread portion, and is in a range in the tire width direction, and in this range. The pneumatic tire according to claim 6, wherein the protective rubber layer has a thickness of 0.5 to 2.0 mm.   The pneumatic tire according to claim 1, wherein the protective rubber layer is made of butyl rubber.

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