JP5798316B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire using a polymer laminate as an inner liner.

  In recent years, tires have been made lighter due to the strong social demand for low fuel consumption of vehicles, and among the tire members, the amount of air leakage from the inside of the pneumatic tire to the outside is arranged inside the tire. In the inner liner which plays a role of improving the air permeation resistance by reducing the (air permeation amount), weight reduction and the like have been performed.

  Currently, butyl rubber containing, for example, 70 to 100% by weight of butyl rubber and 30 to 0% by weight of natural rubber is used for the rubber composition for the inner liner. Permeability is obtained. Inner liners using butyl rubber usually require a thickness of about 0.6 to 1.0 mm for passenger car tires and about 1.0 to 2.0 mm for truck and bus tires. Therefore, there is a demand for a polymer that has better air permeation resistance than butyl rubber and that can reduce the thickness of the inner liner layer.

  For example, Patent Document 1 discloses a laminate for improving the adhesion between an inner liner layer and a rubber layer. In this document, by providing adhesive layers on both sides of the inner liner layer, the adhesive layers come into contact with each other at the overlapping part of the inner liner layer, and are firmly bonded by heating, improving air pressure retention It describes what you can do. However, the adhesive layer for superimposing the inner liner layer comes into contact with the bladder in a heated state in the vulcanization process, and there is a problem that it adheres to and adheres to the bladder.

  In Patent Document 2, the distance in the tire radial direction from the surface passing through the center of the cord cross section of the thermoplastic resin film and the carcass ply layer to the thermoplastic resin film is set within a predetermined range, so A pneumatic tire is disclosed in which a shearing force is selectively applied to a thermoplastic resin film having a high rate. However, this thermoplastic resin film has poor adhesion during vulcanization and stress is concentrated on the thermoplastic resin film having a high Young's modulus during running, and the thermoplastic resin film and the carcass ply peel off during long running. It may occur or a crack may occur in the thermoplastic resin film. As a result, the function as an inner liner may be impaired.

  Patent Document 3 describes a pneumatic tire capable of simultaneously realizing suppression of a decrease in air pressure, improvement in durability, and improvement in fuel consumption, with respect to 100 parts by mass of a rubber component made of natural rubber and / or synthetic rubber. There is disclosed a pneumatic tire using a rubber composition for an inner liner containing a specific ethylene-vinyl alcohol copolymer in a range of 15 to 30 parts by mass as an inner liner layer. However, in the pneumatic tire, the thickness of the inner liner layer is as thick as 1 mm, and improvement is not sufficient in terms of weight reduction of the tire.

  Patent Literature 4 discloses a pneumatic tire in which an inner liner layer is formed using nylon having a low air permeability, and adhesion with a tire inner surface or a carcass layer, which is a rubber composition, can be improved. However, in the technique of Patent Document 4, in order to form a nylon film layer, it is necessary to apply a rubber paste made of a rubber composition after the nylon film is subjected to RFL treatment, which complicates the process. . Further, in the vulcanization process, generally, a bladder body is inserted into an unvulcanized tire (raw tire) housed in a mold, and the bladder body is inflated and pressed against the inner surface of the mold from the inside of the unvulcanized tire. The tire vulcanization method that performs vulcanization molding is adopted. However, in the inner liner layer of Patent Document 4, the nylon film layer and the bladder are in contact with each other in a heated state, and the nylon film layer adheres and adheres to the bladder. There is also a problem of being broken.

JP-A-9-19987 JP 2004-136766 A JP 2007-291256 A JP-A-9-165469

  An object of the present invention is to improve the basic stability of an inner liner such as air permeation resistance and bending fatigue resistance in a pneumatic tire including an inner liner, achieve weight reduction, and further improve steering stability. To do.

  The present invention is a pneumatic tire provided with an inner liner disposed inside a tire and a carcass ply provided adjacent to the inner liner and having a cord embedded in a rubber layer, the inner liner Includes a styrene-isobutylene-styrene triblock copolymer (hereinafter also referred to as “SIBS”), a first layer having a thickness of 0.05 mm to 0.6 mm, and a styrene-isoprene-styrene triblock copolymer. It includes at least one of a polymer (hereinafter also referred to as “SIS”) and a styrene-isobutylene diblock copolymer (hereinafter also referred to as “SIB”), and has a thickness of 0.01 mm to 0.3 mm. The second layer is composed of a polymer laminate, and the second layer is disposed so as to be in contact with the rubber layer of the carcass ply. When the diameter is D, the plane passing through the cross section center of the cord, the distance L to the second layer to provide a pneumatic tire is greater than or equal to 0 (1 + D / 2) mm or less.

  In a preferred embodiment of the present invention, the first layer consists of a styrene-isobutylene-styrene triblock copolymer. In another preferred embodiment of the present invention, the first layer comprises 99 to 70% by mass of a styrene-isobutylene-styrene triblock copolymer and 1 to 30% by mass of an ethylene-vinyl alcohol copolymer. The ethylene-vinyl alcohol copolymer preferably has an ethylene component content of 25 to 50 mol%.

In still another preferred embodiment of the present invention, the first layer has a layered clay mineral content of 0.1 to 50 masses in which an organic compound is intercalated with respect to 100 mass parts of a styrene-isobutylene-styrene triblock copolymer. Further includes a section. In still another preferred embodiment of the present invention, the first layer has a weight average molecular weight of 1 × 10 ² to 1 × 10 ⁶ with respect to 100 parts by mass of styrene-isobutylene-styrene triblock copolymer, and is softened. It further contains 1 to 100 parts by mass of a tackifier having a point of 50 ° C. to 150 ° C., and the second layer is 20 to 90% by mass of a styrene-isoprene-styrene triblock copolymer or a styrene-isobutylene diblock copolymer. Styrene-isobutylene-styrene triblock copolymer. In addition to the first layer, the second layer has a total amount of 100 parts by mass of the styrene-isoprene-styrene triblock copolymer or the styrene-isobutylene diblock copolymer and the styrene-isobutylene-styrene triblock copolymer. On the other hand, it is preferable that 1-100 mass parts of tackifiers whose weight average molecular weight is 1 * 10 < ² > -1 * 10 < ⁶ > and whose softening point is 50 to 150 degreeC are further included.

  The SIBS preferably has a styrene component content of 10 to 30% by mass. The SIS preferably has a styrene component content of 10 to 30% by mass and a weight average molecular weight of 100,000 to 290,000.

  The SIB is linear, preferably has a styrene component content of 10 to 35% by mass, and a weight average molecular weight of 40,000 to 120,000.

  In the present invention, it is also preferred that the boundary surface between the polymer laminate constituting the inner liner and the rubber layer of the carcass ply has an uneven shape.

  According to this invention, since the said polymer laminated body is used for an inner liner, the thickness can be made thin, maintaining an air barrier property, and also adhesiveness with an adjacent rubber layer can be improved. In a pneumatic tire using this polymer laminate as an inner liner, bending fatigue resistance and steering stability are improved.

It is a typical sectional view showing the right half of the pneumatic tire concerning one embodiment of the present invention. It is a typical sectional view expanding and showing the neighborhood of a boundary of a carcass ply and an inner liner in a pneumatic tire concerning one embodiment of the present invention. It is a typical sectional view expanding and showing the neighborhood of a boundary of a carcass ply and an inner liner in a pneumatic tire concerning one embodiment of the present invention. It is typical sectional drawing of the inner liner which concerns on one embodiment of this invention. It is typical sectional drawing of the inner liner which concerns on one embodiment of this invention. It is typical sectional drawing of the inner liner which concerns on one embodiment of this invention. It is typical sectional drawing of the inner liner which concerns on one embodiment of this invention.

  The present invention relates to a pneumatic tire including at least an inner liner disposed inside a tire and a carcass ply provided adjacent to the inner liner and having a cord embedded in a rubber layer. In the pneumatic tire of the present invention, the inner liner is composed of at least two polymer laminates. The first layer includes a styrene-isobutylene-styrene triblock copolymer (SIBS) and has a thickness of 0.05 mm to 0.6 mm. The second layer includes at least one of styrene-isoprene-styrene triblock copolymer (SIS) and styrene-isobutylene diblock copolymer (SIB), and has a thickness of 0.01 mm to 0.3 mm.

  The second layer is disposed so as to be in contact with the rubber layer of the carcass ply, and when the diameter of the cord embedded in the rubber layer is D, from the plane passing through the center of the cross section of the cord to the second layer The distance L is 0 or more and (1 + D / 2) mm or less.

  The pneumatic tire of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a right half of a pneumatic tire according to an embodiment of the present invention, which is typically used as a pneumatic tire for passenger cars. A pneumatic tire 1 shown in FIG. 1 includes a tread portion 2, sidewall portions 3 and bead portions 4 arranged so as to form a toroid shape from both ends of the tread portion 2. Further, a bead core 5 is embedded in the bead portion 4. Further, a carcass ply 6 provided from one bead portion 4 to the other bead portion 4 (not shown) and folded at both ends around the bead core 5 and on the outer side of the crown portion of the carcass ply 6. Are arranged with a belt layer 7 composed of at least two plies.

  The belt layer 7 usually intersects two plies made of steel cords or cords such as aramid fibers with respect to the tire circumferential direction so that the cords are usually at an angle of 5 to 30 °. Are arranged as follows. In addition, a topping rubber layer can be provided on both outer sides of the belt layer 7 to reduce peeling at both ends of the belt layer 7. The carcass ply 6 has cords made of organic fibers such as polyester, nylon, and aramid arranged at approximately 90 ° in the tire circumferential direction, and the bead core 5 has a region surrounded by the carcass ply 6 and its folded portion. A bead apex 8 extending from the upper end in the direction of the sidewall portion 3 is disposed.

  An inner liner 9 is disposed on the inner side in the tire radial direction of the carcass ply 6 from one bead portion 4 to the other bead portion 4 (not shown).

  FIG. 2 is a schematic cross-sectional view showing an enlarged vicinity of the boundary between the carcass ply and the inner liner in the pneumatic tire according to the embodiment of the present invention. Referring to FIG. 2, the inner liner 9 according to the present invention is composed of a polymer laminate including a first layer IL1 and a second layer IL2. The second layer IL2 is in contact with the rubber layer 6a constituting the carcass ply 6 and forms a boundary surface S. The carcass ply 6 has a plurality of cords K embedded in a rubber layer 6a at regular intervals.

  Here, in the pneumatic tire of the present invention, when the diameter of the cord K is D, the surface passing through the cross-sectional center of the cord K (the surface formed by connecting the cross-sectional centers of the cords K) is second from the KC. The distance L to the layer IL2 (that is, the distance to the boundary surface S) is 0 or more and (1 + D / 2) mm or less.

  SIS and SIB constituting the second layer IL2 have higher rigidity than the rubber layer 6a of the carcass ply. Therefore, by making the distance L as small as (1 + D / 2) mm or less, shear stress acts in the tire circumferential direction of the second layer IL2, and the shear rigidity in the tire circumferential direction is improved. As a result, it is possible to improve the steering stability during travel of the pneumatic tire. On the other hand, when the distance L is smaller than 0 mm, the restraining force between the cords K of the carcass ply 6 is reduced, the cord K interval is easily changed, and the rigidity in the tire circumferential direction is lowered. Note that the distance L is smaller than 0 mm means that the boundary surface S between the rubber layer 6a and the second layer IL2 constituting the carcass ply 6 is closer to the side wall portion 3 than the surface KC passing through the cross-sectional center of the cord K. Means to be located.

  FIG. 3 is an enlarged schematic sectional view showing the vicinity of the boundary between the carcass ply and the inner liner in a pneumatic tire according to another embodiment of the present invention. As shown in FIG. 3, the second layer IL2 of the polymer laminate is intruded between the cords of the carcass ply 6 so that the boundary surface S between the second layer IL2 and the rubber layer 6a is uneven. May be formed. In the embodiment shown in FIG. 3, the distance L from the surface KC passing through the cross-sectional center of the cord K to the boundary surface S between the rubber layer 6a and the second layer IL2 is substantially zero. Even with this configuration, the shear rigidity in the tire circumferential direction is improved, and as a result, the handling stability of the pneumatic tire during traveling can be improved. Note that the distance L when the boundary surface S has an uneven shape means an average value of the shortest distance L 'to the boundary surface S between the rubber layer 6a and the second layer IL2.

<Inner liner (polymer laminate)>
In the present invention, the inner liner includes a first layer having a thickness of 0.05 mm to 0.6 mm containing a styrene-isobutylene-styrene triblock copolymer (SIBS), a styrene-isoprene-styrene triblock copolymer (SIS). ) And a styrene-isobutylene diblock copolymer (SIB) and a second layer having a thickness of 0.01 mm to 0.3 mm.

[First layer]
(1) Styrene-isobutylene-styrene triblock copolymer The first layer contains a styrene-isobutylene-styrene triblock copolymer (SIBS). Due to the isobutylene block of SIBS, the polymer film made of SIBS has excellent air permeation resistance. Therefore, a pneumatic tire excellent in air permeation resistance can be obtained by using an inner liner having a first layer containing SIBS.

  Furthermore, since SIBS has a completely saturated molecular structure other than an aromatic ring, it is difficult to cause deterioration hardening and has excellent durability. Therefore, a pneumatic tire excellent in durability can be obtained by using an inner liner provided with the 1st layer containing SIBS.

  As described above, according to the pneumatic tire to which the inner liner including the first layer including SIBS is applied, the air permeation resistance can be ensured. Therefore, it is not necessary to use a halogenated rubber having a high specific gravity, which has been conventionally used for imparting air permeation resistance, such as a halogenated butyl rubber, and even if this is used, the amount used can be reduced. Is possible. As a result, the weight of the tire can be reduced, and as a result, an effect of improving fuel consumption can be obtained.

  The molecular weight of SIBS is not particularly limited, but it is preferable that the weight average molecular weight by GPC measurement is 50,000 to 400,000 from the viewpoint of rubber elasticity and fluidity of SIBS, moldability to inner liner, and the like. If the weight average molecular weight is less than 50,000, the rubber elasticity, tensile strength and tensile elongation of SIBS may be reduced. Moreover, when it exceeds 400,000, there exists a possibility that the moldability (extrusion processability etc.) to an inner liner may fall by the fall of the fluidity | liquidity of SIBS. SIBS is preferably 10 to 40% by mass, more preferably 10 to 30% by mass of the styrene component in SIBS, from the viewpoint of improving air permeability and durability. More preferably, it is 14-23 mass%. The molar ratio (isobutylene / styrene) of the isobutylene component and styrene constituting SIBS is preferably 40/60 to 95/5 from the viewpoint of rubber elasticity of SIBS.

  The degree of polymerization of each block constituting the SIBS may be about 10,000 to 150,000 isobutylene blocks from the viewpoint of rubber elasticity and handleability of SIBS (becomes liquid when the degree of polymerization is less than 10,000). Moreover, it is preferable that a styrene block is about 5,000-30,000.

  SIBS can be obtained by a general vinyl compound polymerization method such as a living cationic polymerization method. For example, JP-A-62-48704 and JP-A-64-62308 disclose that living cationic polymerization of isobutylene and other vinyl compounds is possible, and isobutylene as a vinyl compound and other compounds are used as living compounds. It is disclosed that a polyisobutylene block copolymer can be produced by cationic polymerization. In addition to this, a method for producing a vinyl compound polymer by a living cationic polymerization method is disclosed in, for example, US Pat. No. 4,946,899, US Pat. No. 5,219,948, and Japanese Patent Laid-Open No. 3-174403. It is described in.

  Since SIBS has no double bond other than an aromatic ring in the molecule, it is more stable to ultraviolet rays than a polymer having a double bond in the molecule, such as polybutadiene, and is therefore resistant to weathering. Good properties. In addition, the refractive index (nD) at 20 ° C. of light having a wavelength of 589 nm, despite having no double bond other than an aromatic ring in the molecule and being a saturated rubbery polymer, is a polymer handbook. [1989: Wiley (Polymer Handbook, Willy, 1989)], it is 1.506. This is significantly higher than other saturated rubbery polymers such as ethylene-butene copolymers.

(2) Ethylene-vinyl alcohol copolymer The first layer can be composed of only SIBS, but can contain an ethylene-vinyl alcohol copolymer (hereinafter also referred to as “EVOH”) together with SIBS. Constructing the first layer from SIBS and EVOH is advantageous in the following points.
(A) The rigidity in the tire circumferential direction of the pneumatic tire can be further improved, and thereby the steering stability during traveling of the pneumatic tire can be further improved.
(B) The air permeation resistance (air barrier property) of the inner liner (and therefore the pneumatic tire) can be further improved. Thereby, an inner liner can be made still thinner. This leads to weight reduction of the tire and thus improvement of fuel consumption.
(C) The adhesive strength between the first layer and the second layer is high even when the first layer does not contain EVOH because both of these layers have styrene blocks. By containing EVOH, the adhesive strength between the first layer and the second layer can be further improved. Thereby, even in a state where the inner liner is thinned, the steering stability of the pneumatic tire can be further improved.
(D) The rubber composition containing SIBS for forming the first layer, and thus the adhesive strength of the first layer is further improved. Thereby, problems such as the rubber composition layer forming the first layer falling off during tire molding are less likely to occur, and the molding processability of the pneumatic tire can be further improved.

  Due to the ethylene-derived part of EVOH, the compatibility with other compounding agents contained in the rubber composition for forming the first layer is good, so the ethylene-vinyl alcohol copolymer is contained in the first layer. It can exist in a finely sized dispersed form. On the other hand, EVOH has good air barrier properties due to the contribution of vinyl alcohol-derived sites. Therefore, EVOH having excellent air barrier properties is dispersed in an island shape in a fine size in the first layer, and thus, even when the inner liner is thin, good air barrier properties are expressed. . This means that the weight of the tire is reduced and the fuel consumption is improved.

  When the first layer includes EVOH together with SIBS, the EVOH content in the first layer is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass. When the EVOH content is less than 1% by mass, the effects of EVOH shown in the above (a) to (d) tend not to be sufficiently obtained. On the other hand, if the EVOH content exceeds 30% by mass, the hardness increases and the bending fatigue property of the inner liner may be reduced.

  On the other hand, when the first layer contains EVOH together with SIBS, the content of SIBS in the first layer is preferably 99 to 70% by mass. The content is more preferably 95% by mass or less, further preferably 90% by mass or less, and more preferably 80% by mass or more. When the SIBS content is 70% by mass or more, an inner liner having excellent air permeation resistance and durability and excellent bending fatigue resistance can be obtained. Moreover, the effect by EVOH shown by said (a)-(d) is fully acquired because content of SIBS is 99 mass% or less.

  The ethylene-vinyl alcohol copolymer (EVOH) has the following general formula (I):

(Wherein, m and n are each independently 1 to 100, and x is 1 to 1000), and is preferably an ethylene-vinyl alcohol copolymer.

  In the general formula (I), m and n are 1 or more in order to constitute EVOH. On the other hand, when m and n are each 100 or less, an ethylene-vinyl alcohol copolymer having compatibility with other compounding agents in the rubber composition and air barrier properties can be obtained. It is more preferable that m is 5 or more in terms of better compatibility with other compounding agents in the rubber composition. Further, n is more preferably 5 or more from the viewpoint of better air barrier properties. On the other hand, m is more preferably 95 or less, and even more preferably 80 or less, since it is difficult to impair the air barrier property due to the vinyl alcohol-derived site. In addition, n is more preferably 95 or less, and even more preferably 80 or less, since it is difficult to impair the expression of good compatibility with other compounding agents in the rubber composition due to the ethylene-derived site.

  In the general formula (I), x is 1 or more in order to constitute EVOH. On the other hand, when x is 1000 or less, kneadability at the time of preparing the rubber composition for forming the first layer is ensured, and a rubber composition in which EVOH is uniformly dispersed, and thus the first layer is obtained. X is preferably 10 or more because compatibility with other compounding agents in the rubber composition and air barrier properties are well expressed, and x is 500 or less because kneadability becomes better. It is preferable that it is 100, and it is more preferable that it is 100 or less.

  EVOH represented by the above general formula (I) preferably contains an ethylene component in a range of 25 to 50 mol% from the viewpoint of compatibility with SIBS.

  As the EVOH constituting the first layer, EVOH represented by the above general formula (I) may be used. Examples of such EVOH include EVOH containing sites derived from other copolymer components in addition to sites derived from ethylene and sites derived from vinyl alcohol. In this case, the EVOH content in the first layer means the total content of the ethylene-derived site and the vinyl alcohol-derived site.

  The molecular structure of EVOH can be confirmed by, for example, an infrared absorption spectrum (IR) or a nuclear magnetic resonance spectrum (NMR).

(3) Organically treated clay mineral The first layer can contain an organically treated clay mineral together with SIBS or with SIBS and EVOH. By including the organically treated clay mineral in the first layer, the rubber strength and rubber rigidity of SIBS can be greatly improved, thereby further improving the steering stability during running of the pneumatic tire. it can.

  When the first layer contains an organically treated clay mineral together with SIBS, the content of the organically treated clay mineral in the first layer is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of SIBS. More preferably, it is 5-30 mass parts. If the content of the organically treated clay mineral is less than 0.1 parts by mass with respect to 100 parts by mass of SIBS, the effect of further improving the steering stability cannot be obtained sufficiently. Further, the air permeability and tensile properties at high temperature of the rubber composition for forming the first layer tend to be lowered. On the other hand, when the content of the organically treated clay mineral exceeds 50 parts by mass with respect to 100 parts by mass of SIBS, the hardness of the rubber composition becomes too large, and the bending fatigue property of the inner liner may be lowered.

  Here, the organically treated clay mineral refers to a layered clay mineral in which an organic compound is intercalated. When the organic compound is intercalated between the layers of the layered clay mineral, the layers are expanded and the dispersibility into the polymer is improved.

  The layered clay mineral is a kind of layered silicate mineral, and its crystal structure is a structure in which three layers of silicic acid tetrahedral layer-alumina octahedral layer-silicic acid tetrahedral layer are stacked, and the unit layer has a thickness of about 10 mm. It has a very thin plate shape (1 nm) and a spread of 0.1 to 1 μm.

A typical example of the layered clay mineral is montmorillonite. In montmorillonite, a portion of Al, which is the central atom of the alumina octahedron layer in the crystal structure, is replaced with Mg, resulting in insufficient positive charge, and each crystal layer itself is negatively charged. By incorporating cations such as ⁺ , K ⁺ , Ca ²⁺ , Mg ^2+, etc., the charge shortage is neutralized and a stable state is obtained. Therefore, montmorillonite exists in a state in which a number of crystal layers are overlapped.

  When water contacts the surface of the montmorillonite plate-like crystal layer, water molecules hydrate to the exchangeable cations between the layers, and the layers expand. Further, by intercalating an organic compound between layers using the cation exchange property of montmorillonite, the layers are expanded and the dispersibility in organic solvents and polymers is improved.

  Examples of the layered clay mineral that can be used in the present invention include montmorillonite (especially sodium montmorillonite, magnesium montmorillonite, and calcium montmorillonite), bentonite, kaolinite, nonlite, beidellite, vorconskite, hectorite, saponite, sauconite, sovokyite, and stive. Phyllosilicates such as smectite clays such as sincite, subbinite, vermiculite, mica minerals such as illite and illite / smectite mixtures (lectretite, talosobite, ladykite and mixtures of the above clay compounds with illite) or Examples thereof include attapulgite and sepiolite hydrotalcite-based layered compounds. Of these, smectite clay is preferable, and montmorillonite clay is particularly preferable. Bentonite containing a smectite clay mineral may be used. These layered clay minerals are generally obtained by collecting natural minerals and performing a predetermined refining operation. These synthetic clays can be used interchangeably.

  Examples of the organic compound that can be used as an intercalant include organic compounds having a polar group that is easily ionized in the molecule. An organic compound having a polar group causes a strong interaction with the surface of a layer covered with negative ions such as oxygen ions of smectite clay minerals, and enters (intercalates) between layers of layered clay minerals. It is thought to expand and expand.

  As the organic compound, those having an alkyl group having 6 or more carbon atoms and having a polar group ionizing at the terminal are preferable. Examples of such organic compounds include those having a hydroxyl group or a carboxyl group, aldehydes, amines, amides, or quaternary ammonium salts.

  Examples of the organic compound having a hydroxyl group include aliphatic alcohols such as octyl alcohol and nonyl alcohol; alcohols such as aromatic alcohol having an alkyl group, and phenols.

  Examples of the organic compound having a carboxyl group include linear fatty acids such as stearic acid, palmitic acid, and lauric acid, linear alkenoic acids such as oleic acid, dienic acids such as linoleelaidic acid, and polyunsaturated fats such as trienoic acid. Family acids and the like. Examples of aldehydes include hexyl aldehyde.

  Examples of amines or amides include polar organic compounds having one or more amines or amides. Specific examples include alkylamines, aminocycloalkanes, aminocycloalkane substituents, cycloaliphatic diamines, fatty acids. Group amines, alkyl aromatic amines, alkyl diaryl amines, aliphatic amides and the like. The amines or amides may be any of primary, secondary, tertiary amines or amides. Of these, alkylamines, aliphatic amines, alkylaromatic amines, and alkyldiarylamines are preferable. The said organic compound may use only 1 type and may use 2 or more types together.

  Preferred amines include primary amines such as 1-hexylamine, 1-heptylamine, 1-octylamine, 1-nomylamine, 1-dodecylamine, 1-hexadecylamine, 1-octadecylamine, oleylamine; Secondary amines such as dodecylamine, di-n-hexadecylamine, di-n-octadecylamine; dimethyl-n-octylamine, dimethyl-n-decylamine, dimethyl-n-tetradecylamine, dimethyl-n-hexa Tertiary amines such as decylamine, dimethyl-n-octadecylamine, dimethyloleylamine; di-n-decylmethylamine dicocoalkylmethylamine, tri-n-octylamine, tri-n-decylamine, tri-n-hexadecyl Aliphatic amines such as amines can be mentioned.

  Preferable amides include hexylamide, heptylamide, octylamide, nonylamide, lauramide, myristamide, palmitamide, steramide, palmamid, oleamide, linoleamide and the like.

  In addition, as the organic compound having a polar group, those having a nitrile group or a lactam group, pyridines, esters, surfactants, ethers and the like can be used.

  Examples of the quaternary ammonium salt include dimethyl distearyl ammonium salt, trimethyl stearyl ammonium salt, dimethyl dioctadecyl ammonium, dimethyl benzyl octadecyl ammonium, and trimethyl octadecyl ammonium.

  As a method for intercalating an organic compound into the layered clay mineral, a known method can be employed. For example, in order to bring the montmorillonite clay mineral into contact with the organic compound, the layered clay mineral is preliminarily made to contain water of about 0.1 to 20 times its mass, and then contacted with the organic compound and the montmorillonite clay mineral. To obtain an organically treated clay mineral.

  The cation exchange amount of the organic compound in the organically treated clay mineral is preferably 50 to 200 meg / 100 g.

(4) Tackifier The first layer may contain a tackifier together with SIBS, or together with SIBS and EVOH and / or organically treated clay mineral. By including a tackifier in the first layer, the appearance of the pneumatic tire can be improved by preventing air-in, and durability, handling stability during running, and air permeation resistance (air barrier properties) Further, tire characteristics such as rolling resistance can be further improved. In particular, by improving the adhesive strength between the first layer and the second layer and / or between the second layer and the carcass ply, it is possible to dramatically improve the handling stability during traveling. Moreover, the addition of the tackifier further improves the adhesive strength of the rubber composition containing SIBS for forming the first layer, and thus the first layer. Thereby, problems such as the rubber composition layer forming the first layer falling off during tire molding are less likely to occur, and the molding processability of the pneumatic tire can be further improved. When a tackifier is contained in both the first layer and the second layer, a more remarkable effect can be obtained. The addition of the tackifier to the second layer will be described in detail later.

  Moreover, since the air permeation resistance (air barrier property) of the inner liner (and therefore the pneumatic tire) can be further improved, the inner liner can be made thinner. This leads to weight reduction of the tire and thus improvement of fuel consumption.

  When a 1st layer contains tackifier with SIBS, it is preferable that content of the tackifier in a 1st layer is 1-100 mass parts with respect to 100 mass parts of SIBS, and is 1-50 mass parts. It is more preferable. The effect mentioned above cannot fully be acquired as content of a tackifier is less than 0.1 mass part with respect to 100 mass parts of SIBS. On the other hand, when the content of the tackifier exceeds 100 parts by mass with respect to 100 parts by mass of SIBS, steering stability and air permeation resistance during running tend to decrease.

Here, “tackifier” refers to an additive for enhancing the tackiness of the rubber composition forming the inner liner. The tackifier preferably has a weight average molecular weight of 1 × 10 ² to 1 × 10 ⁶ by GPC measurement, and preferably has a softening point in the range of 50 ° C. to 150 ° C. When the weight average molecular weight is less than 1 × 10 ² , the viscosity is too low, which is disadvantageous in terms of moldability to the inner liner. On the other hand, when the weight average molecular weight exceeds 1 × 10 ⁶ , there is a tendency that tackiness is not sufficiently applied to the first layer. Further, when the softening point is less than 50 ° C., the rubber hardness is greatly reduced and the steering stability tends to be lowered. On the other hand, when the softening point is higher than 150 ° C., the tackifying effect is insufficient. Tend. The softening point is measured using a differential scanning calorimeter (“DSC 2910” manufactured by TA Instruments Japan Co., Ltd.).

Examples of the tackifier that can be used in the present invention include the following.
[C9 petroleum resin]
C9 petroleum resin is obtained by polymerizing the C5 to C9 fraction (mainly C9 fraction), which is the remainder obtained by removing useful compounds such as ethylene, propylene, and butadiene from the thermal decomposition product of naphtha in a mixed state. Aromatic petroleum resin. All are trade names, Alcon P70, P90, P100, P115, P125, P140, M90, M100, M115, M135 (all Arakawa Chemical Industries, Ltd., softening point 70-145 ° C.); , P100, P125, P140 (all manufactured by Idemitsu Petrochemical Co., Ltd., aromatic copolymer hydrogenated petroleum resin, softening point 100-140 ° C., weight average molecular weight 700-900, bromine number 2.0-6.0 g) / 100 g); Petcoal XL (manufactured by Tosoh Corporation).

[C5 petroleum resin]
C5 petroleum resin is obtained by polymerizing a C4 to C5 fraction (mainly C5 fraction), which is a residue obtained by removing useful compounds such as ethylene, propylene, and butadiene from a thermal decomposition product of naphtha in a mixed state. It is an aliphatic petroleum resin. All are trade names: Highlets G100 (Mitsui Petrochemical Co., Ltd., softening point 100 ° C.); Marcarets T100AS (Maruzen Oil Co., Ltd., softening point 100 ° C.); Escorez 1102 (Tonex Corp., softening point) 110 ° C.).

[Terpene resin]
All are trade names, YS Resin PX800N, PX1000, PX1150, PX1250, PXN1150N, Clearon P85, P105, P115, P125, P135, P150, M105, M115, K100 (all from Yashara Chemical Co., Ltd., softening point 75-160 ° C).

[Aromatic modified terpene resin]
All are trade names and include YS resin TO85, TO105, TO115, and TO125 (all manufactured by Yashara Chemical Co., Ltd., softening point 80 to 130 ° C.).

[Terpene phenol resin]
All are trade names, Tamanoru 803L, 901 (Arakawa Chemical Industries, softening point 120-160 ° C); YS Polystar U115, U130, T80, T100, T115, T130, T145, T160 (all Yashara Chemical Co., Ltd. ), Softening point 75-165 ° C).

[Coumarone resin]
There is a coumarone resin (manufactured by Kobe Oil Chemical Co., Ltd.) having a softening point of 90 ° C.

[Coumaron Inden Oil]
There is 15E (made by Kobe Oil Chemical Co., Ltd., pour point 15 ° C.) under the trade name.

[Rosin ester]
All are trade names, Ester gum AAL, A, AAV, 105, AT, H, HP, HD (all Arakawa Chemical Industries, softening point 68-110 ° C.); Harrier Star TF, S, C, There are DS70L, DS90, and DS130 (all manufactured by Harima Kasei Co., Ltd., softening point 68-138 ° C).

[Hydrogenated rosin ester]
All are trade names and include superesters A75, A100, A115, and A125 (all manufactured by Arakawa Chemical Industries, Ltd., softening point 70 to 130 ° C.).

[Alkylphenol resin]
There is Tamanoru 510 (manufactured by Arakawa Chemical Industries, softening point 75-95 ° C.) under the trade name.

[DCPD]
There is Escoretz 5300 (manufactured by Tonex Co., Ltd., softening point 105 ° C.) under the trade name.

  Among the above, the fully hydrogenated petroleum resin of C9 petroleum resin has good compatibility with the SIBS constituting the first layer, the adhesive strength of the first layer, and the first and second layers. And / or is advantageous because it has a high effect of improving the adhesive strength between the second layer and the carcass ply.

  When the first layer contains a tackifier, the polymer component of the second layer is 20 to 90% by mass of styrene-isoprene-styrene triblock copolymer (SIS) or styrene-isobutylene diblock copolymer (SIB). And 10 to 80% by mass of styrene-isobutylene-styrene triblock copolymer (SIBS). By using SIBS together with SIS or SIB as the polymer component of the second layer, the effect of the tackifier can be sufficiently obtained. However, when the content of SIBS exceeds 80% by mass in the polymer component, the adhesive strength between the second layer and the carcass ply tends to decrease. Moreover, it exists in the tendency for the effect of a tackifier to fully not be acquired as content of SIBS is less than 10 mass% in a polymer component.

(5) Thickness of the first layer The thickness of the first layer including SIBS (T1 in FIG. 1) is 0.05 to 0.6 mm. When the thickness T1 of the first layer is less than 0.05 mm, the vulcanization of the raw tire in which the polymer laminate is applied to the inner liner causes the first layer to be broken by the press pressure, and the resulting tire has an air leak. Phenomena may occur. On the other hand, when the thickness T1 of the first layer exceeds 0.6 mm, the tire weight increases and the fuel efficiency performance decreases. The thickness T1 of the first layer is preferably 0.05 to 0.4 mm. The first layer is a film of thermoplastic resin or thermoplastic elastomer such as SIBS and rubber composition containing additives such as EVOH, an organically treated clay mineral, and a tackifier that are optionally added. It can be obtained by forming into a film by an ordinary method of converting to a film. The rubber composition may contain other additives such as a reinforcing agent, a vulcanizing agent, a vulcanization accelerator, various oils, an anti-aging agent, a softening agent, a plasticizer, and a coupling agent.

[Second layer]
(1) Styrene-isoprene-styrene triblock copolymer and styrene-isobutylene diblock copolymer The second layer comprises a styrene-isoprene-styrene triblock copolymer (SIS) and a styrene-isobutylene diblock copolymer (SIS SIB). Since the isoprene block of SIS and the isobutylene block of SIB are soft segments, the polymer film containing SIS or SIB tends to be vulcanized and bonded to the rubber component. Therefore, a pneumatic tire excellent in the adhesive strength between the inner liner and the carcass ply rubber layer can be obtained by using the inner liner including the second layer containing SIS or SIB. Thereby, durability of a pneumatic tire and steering stability at the time of driving | running | working can be improved.

  The molecular weight of SIS is not particularly limited, but from the viewpoint of rubber elasticity of SIS and moldability to an inner liner, the weight average molecular weight by GPC measurement is preferably 100,000 to 290,000. If the weight average molecular weight is less than 100,000, the rubber elasticity and tensile strength of SIS may be lowered. Moreover, when it exceeds 290,000, there exists a possibility that the moldability (extrusion processability etc.) to an inner liner may fall by the fall of the fluidity | liquidity of SIS. The content of the styrene component in the SIS is preferably 10 to 30% by mass from the viewpoint of the adhesiveness and rubber elasticity of the SIS, and the adhesive strength of the second layer to the first layer and the carcass ply.

  The degree of polymerization of each block constituting the SIS is preferably about 500 to 5,000 for the isoprene block and about 50 to 1,500 for the styrene block from the viewpoint of rubber elasticity and handleability of the SIS. It is preferable.

  The SIS can be obtained by a general vinyl compound polymerization method such as a living cationic polymerization method.

  It is preferable to use a linear SIB from the viewpoint of rubber elasticity and the adhesive strength of the second layer to the first layer and the carcass ply. The molecular weight of SIB is not particularly limited, but it is preferable that the weight average molecular weight by GPC measurement is 40,000 to 120,000 from the viewpoint of rubber elasticity of SIB and moldability to the inner liner. If the weight average molecular weight is less than 40,000, the rubber elasticity and tensile strength of SIB may be lowered. Moreover, when it exceeds 120,000, there exists a possibility that the processability (extrusion processability etc.) to an inner liner may fall by the fall of the fluidity | liquidity of SIB. The content of the styrene component in the SIB is preferably 10 to 35% by mass from the viewpoint of the adhesiveness and rubber elasticity of the SIB and the adhesive strength of the second layer to the first layer and the carcass ply.

  The degree of polymerization of each block constituting the SIB is preferably about 300 to 3,000 for the isobutylene block and about 10 to 1,500 for the styrene block from the viewpoint of rubber elasticity and handleability of the SIB. It is preferable.

  SIB can be obtained by a general vinyl compound polymerization method such as a living cationic polymerization method. For example, in International Publication No. 2005/033035, methylcyclohexane, n-butyl chloride and cumyl chloride are added to a stirrer, cooled to −70 ° C., reacted for 2 hours, and then a large amount of methanol is added. A method is disclosed in which the reaction is stopped and vacuum dried at 60 ° C. to obtain SIB.

  The second layer may contain both SIS and SIB. In this case, the second layer may have a single layer structure including both SIS and SIB, or may have a multilayer structure including a layer including SIS and a layer including SIB layer.

  The second layer is made of styrene-isoprene-butadiene-styrene copolymer (SIBS), styrene-ethylene-butene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-ethylene. One or more selected from the group consisting of ethylene / propylene / styrene copolymer (SEEPS), styrene / butadiene / butylene / styrene copolymer (SBBS), and those obtained by introducing an epoxy group into these thermoplastic elastomers A thermoplastic elastomer may be included. The same applies to the first layer. Examples of the thermoplastic elastomer having an epoxy group include an epoxy-modified styrene-butadiene-styrene copolymer (specific examples include “epoefriend A1020” manufactured by Epoxy SBS Daicel Chemical Industries, Ltd., weight average molecular weight: 100,000). , Epoxy equivalent: 500, etc.).

  The example of the form which the inner liner (polymer laminated body) in this invention can take is shown in FIGS. In the example shown in FIG. 4, the polymer laminate 10 that is an inner liner includes a SIBS layer 11 as a first layer and a SIS layer 12 as a second layer. The polymer laminate 10 is placed toward the outer side in the tire radial direction so that the SIS layer 12 is in contact with the carcass ply 61. Thereby, the adhesive strength between the SIS layer 12 and the carcass ply 61 can be increased in the tire vulcanization process. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well bonded.

  In the example shown in FIG. 5, the polymer laminate 10 includes an SIBS layer 11 as a first layer and an SIB layer 13 as a second layer. The polymer laminate 10 is installed toward the outer side in the tire radial direction so that the SIB layer 13 is in contact with the carcass ply 61. Thereby, the adhesive strength between the SIB layer 13 and the carcass ply 61 can be increased in the tire vulcanizing step. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well bonded.

  In the example shown in FIG. 6, the polymer laminate 10 is configured by laminating a SIBS layer 11 as a first layer, a SIS layer 12 and a SIB layer 13 as a second layer in this order. The polymer laminate 10 is installed toward the outer side in the tire radial direction so that the SIB layer 13 is in contact with the carcass ply 61. Thereby, the adhesive strength between the SIB layer 13 and the carcass ply 61 can be increased in the tire vulcanizing step. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well bonded.

  In the example shown in FIG. 7, the polymer laminate 10 is configured by laminating an SIBS layer 11 as a first layer, an SIB layer 13 as a second layer, and an SIS layer 12 in this order. The polymer laminate 10 is placed toward the outer side in the tire radial direction so that the SIS layer 12 is in contact with the carcass ply 61. Thereby, the adhesive strength between the SIS layer 12 and the carcass ply 61 can be increased in the tire vulcanization process. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well bonded.

  The second layer is formed into a film by a usual method of forming a thermoplastic resin or a thermoplastic elastomer into a film, such as extrusion molding or calendering, from a rubber composition containing SIS and / or SIB and optionally added additives described later. Can be obtained.

(2) Additive The second layer, like the first layer, is EVOH, organically treated clay mineral, tackifier or other additive (reinforcing agent, vulcanizing agent, vulcanization accelerator, various oils, aging Inhibitors, softeners, plasticizers, coupling agents, etc.). Especially, it is preferable that a 2nd layer contains a tackifier. By including a tackifier in the second layer, the adhesion strength between the first layer and the second layer and between the second layer and the carcass ply is improved, thereby improving the handling stability during traveling. Can be made. Moreover, the addition of the tackifier further improves the rubber composition for forming the second layer, and thus the adhesive strength of the second layer. Thereby, problems such as the rubber composition layer forming the second layer falling off during the molding of the tire are less likely to occur, and the molding processability of the pneumatic tire can be further improved. Moreover, since the air permeation resistance (air barrier property) of the inner liner (and therefore the pneumatic tire) can be further improved, the inner liner can be made thinner. This leads to weight reduction of the tire and thus improvement of fuel consumption. More preferably, a tackifier is contained in both the first layer and the second layer.

  When the second layer includes a tackifier, the content of the tackifier in the second layer is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the total amount of SIS and SIB, and 1 to 50 More preferably, it is part by mass. The effect mentioned above cannot fully be acquired as content of a tackifier is less than 0.1 mass part with respect to 100 mass parts of total amounts of SIS and SIB. On the other hand, when the content of the tackifier exceeds 100 parts by mass with respect to 100 parts by mass of the total amount of SIS and SIB, the steering stability and air permeation resistance during running tend to decrease.

The tackifier contained in the second layer preferably has a weight average molecular weight of 1 × 10 ² to 1 × 10 ⁶ by GPC measurement for the same reason as described above, and has a softening point of 50 ° C. to 150 ° C. It is preferably in the range of ° C. Specific examples of the tackifier that can be contained in the second layer are the same as those described above for the first layer. The tackifier contained in the first layer and the tackifier contained in the second layer may be the same or different.

(3) Thickness of the second layer The thickness of the second layer (T2 in FIG. 1) is 0.01 to 0.3 mm. Here, the thickness T2 of the second layer is the thickness of the SIS layer when the second layer is composed of only the SIS layer, and the thickness of the SIB layer when the second layer is composed of only the SIB layer. When the second layer has a multilayer structure such as a two-layer structure of an SIS layer and an SIB layer, it means the total thickness of the multilayer structure. When the thickness T2 of the second layer is less than 0.01 mm, the second layer is broken by pressing pressure during vulcanization of the raw tire in which the polymer laminate is applied to the inner liner, and the vulcanization adhesive strength is reduced. There is a fear. On the other hand, if the thickness T2 of the second layer exceeds 0.3 mm, the tire weight increases and the fuel efficiency performance decreases. The thickness T2 of the second layer is preferably 0.05 to 0.2 mm.

<Method for producing polymer laminate>
The polymer laminate (unvulcanized) uses a rubber composition containing SIBS that forms the first layer and a rubber composition containing at least one of SIS and SIB. For example, any of FIGS. It can be obtained by laminating extrusion such as laminate extrusion or coextrusion in the order shown.

<Pneumatic tire manufacturing method>
A general manufacturing method can be used for the pneumatic tire of the present invention. That is, it can be manufactured by applying the polymer laminate 10 to an inner liner of a raw tire of the pneumatic tire 1 and vulcanizing it together with other members. When the polymer laminate 10 is arranged on the green tire, the second layer (such as the SIS layer 12 or the SIB layer 13) of the polymer laminate 10 is arranged outward in the tire radial direction so as to be in contact with the carcass ply 61. With this arrangement, the adhesive strength between the second layer and the carcass ply 61 can be increased in the tire vulcanization step. The obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well bonded.

  In addition, the compounding of the rubber layer of the carcass ply used for the pneumatic tire of the present invention is a commonly used rubber component such as natural rubber, polyisoprene, styrene-butadiene rubber, polybutadiene rubber, carbon black, silica, etc. What mix | blended the filler can be used.

  Here, when the rubber composition constituting the first layer and / or the second layer of the polymer laminate includes the above tackifier, the rubber composition is softened in the mold at a temperature during vulcanization, for example, 150 to 180 ° C. State (intermediate state between solid and liquid). Therefore, when the mold is opened after vulcanization, the shape of the polymer laminate is deformed when the rubber composition is in a softened state. Moreover, since the reactivity is higher in the softened state than in the solid state, it may stick to and adhere to an adjacent member. Therefore, when the polymer laminate includes a tackifier, it is preferable to provide a cooling step after vulcanization. Examples of the cooling method include a method of rapidly cooling the inside of the bladder to 50 to 120 ° C. within 10 to 300 seconds after vulcanization. As the cooling medium, one or more selected from air, water vapor, water and oil can be used.

  According to the above cooling method, the inner liner can be made thinner regardless of whether the rubber composition contains a tackifier, for example, the inner liner has a thickness of about 0.05 to 0.6 mm. Can be made smaller. This is because the releasability from the bladder of the tire obtained by vulcanization is improved by the cooling step.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples.

  The pneumatic tires of Examples 1 to 11 and Comparative Examples 1 to 5 having the configurations shown in Table 1 and Table 2 were manufactured, and the performance was evaluated.

<Example 1>
(1) Preparation of SIB To a 2 L reaction vessel equipped with a stirrer were added 589 mL of methylcyclohexane (dried with molecular sieves), 613 ml of n-butyl chloride (dried with molecular sieves), and 0.550 g of cumyl chloride. After cooling the reaction vessel to −70 ° C., 0.35 mL of α-picoline (2-methylpyridine) and 179 mL of isobutylene were added. Further, 9.4 mL of titanium tetrachloride was added to initiate polymerization, and the reaction was allowed to proceed for 2.0 hours while stirring the solution at -70 ° C. Next, 59 mL of styrene was added to the reaction vessel, and the reaction was continued for another 60 minutes, and then a large amount of methanol was added to stop the reaction. After removing the solvent and the like from the reaction solution, the polymer was dissolved in toluene and washed twice with water. The toluene solution was added to methanol to precipitate a polymer, and the obtained polymer was dried at 60 ° C. for 24 hours to obtain a linear styrene-isobutylene diblock copolymer (SIB). The obtained SIB had a styrene component content of 15% by mass and a weight average molecular weight of 70,000 as measured by GPC.

(2) Preparation of SIBS As a styrene-isobutylene-styrene triblock copolymer (SIBS), Shibstar SIBSTAR 102T (Shore A hardness 25, styrene component content 25% by mass, manufactured by Kaneka Corporation), weight average by GPC measurement Molecular weight: 100,000) was prepared.

(3) Production of polymer laminate (unvulcanized) The above-mentioned SIBS is used as the polymer for forming the first layer and the above-mentioned SIB is used as the polymer for forming the second layer, and these are twin screw extruders (screw diameter: φ50 mm, L / D: 30, cylinder temperature: 220 ° C.). Thereafter, a polymer laminate was produced using a T-die extruder (screw diameter: φ80 mm, L / D: 50, die lip width: 500 mm, cylinder temperature: 220 ° C., film gauge: 0.3 mm).

(4) Manufacture of a pneumatic tire A 195 / 65R15 size raw tire having the basic structure shown in FIG. 1 in which the polymer laminate is applied to an inner liner is manufactured, and then pressed at 170 ° C. for 20 minutes in the vulcanization process. A pneumatic tire was manufactured by molding. The distance L was 0 mm. The thicknesses of the first layer and the second layer of the inner liner were 0.5 mm and 0.1 mm, respectively. In addition, when applying a polymer laminated body to a green tire, it has arrange | positioned so that a 2nd layer may contact | connect a carcass ply.

In addition, the compounding of the rubber composition used for the rubber layer of the carcass ply is as follows.
Natural rubber (Note 1) 70 parts by weight SBR (Note 2) 30 parts by weight Carbon black (Note 3) 50 parts by weight Process oil (Note 4) 10 parts by weight Anti-aging agent (Note 5) 2 parts by weight Stearic acid (Note 6) ) 2 parts by weight Zinc oxide (Note 7) 6 parts by weight Sulfur (Note 8) 3 parts by weight Vulcanization accelerator (Note 9) 1 part by weight (Note 1) “RSS # 3” made in Thailand,
(Note 2) “Sumitomo SBR1502” manufactured by Sumitomo Chemical Co., Ltd.
(Note 3) “Diamond Black 351H (nitrogen adsorption specific surface area: 66 m ² / g)” manufactured by Mitsubishi Chemical Corporation
(Note 4) “Process X-140” manufactured by Japan Energy Co., Ltd.
(Note 5) “NOCRACK 6C” manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 6) “Stearic acid lees” manufactured by Nippon Oil & Fats Co., Ltd.
(Note 7) “Zinc oxide type 2” manufactured by Mitsui Kinzoku Co., Ltd.
(Note 8) “Seimi Sulfur” manufactured by Nippon Kiboshi Co., Ltd.
(Note 9) “Noxeller NS” manufactured by Ouchi Shinsei Chemical Co., Ltd.

  Further, a polyester 1670 dtex having a diameter (D) of 0.7 mm was used for the cord of the carcass ply.

<Examples 2-3>
A pneumatic tire was manufactured in the same manner as in Example 1 except that the distance L was changed to D / 2 or 0.5 + D / 2.

<Examples 4 to 6>
Air as in Example 1 except that SIBS was used for the first layer, SIS (styrene-isoprene-styrene triblock copolymer) was used for the second layer, and the distance L was set to 0 to 0.5 + D / 2. A tire was produced. Here, the cord diameter (D) is 0.7 mm. D1161JP (15% by mass of styrene component, weight average molecular weight by GPC measurement: 150,000) manufactured by Kraton Polymer Co., Ltd. was used for SIS (the SIS used in the following examples and comparative examples was the same as this). Is).

<Examples 7 to 11>
A pneumatic tire was manufactured in the same manner as in Example 1 except that SIBS was used for the first layer and SIB was used for the second layer, and these thicknesses were changed to change the thickness of the inner liner. The thickness of Example 7 is the largest at 0.6 mm, and the thickness of Example 11 is the smallest at 0.06 mm.

<Comparative Example 1>
A pneumatic tire was prepared in the same manner as in Example 2 except that the polymer film A having a thickness of 1.0 mm obtained by mixing the following ingredients with a Banbury mixer and forming a sheet with a calendar roll was used as an inner liner. Manufactured.

Chlorobutyl (Note 1) 90 parts by weight Natural rubber (Note 2) 10 parts by weight Filler (Note 3) 50 parts by weight (Note 1) “Exon Chlorobutyl 1068” manufactured by ExxonMobil Corporation
(Note 2) TSR20,
(Note 3) “Seast V” (N660, nitrogen adsorption specific surface area: 27 m ² / g) manufactured by Tokai Carbon Co., Ltd.

<Comparative Example 2>
A pneumatic tire was manufactured in the same manner as in Example 2 except that a 0.6 mm thick SIBS layer manufactured by the same method as described above was used as the inner liner.

<Comparative Example 3>
A pneumatic tire was manufactured in the same manner as in Example 2 except that the polymer film B made of a thermoplastic resin having the following composition was used as the inner liner.

Nylon 6 (Note 1) 25.2 parts by weight Nylon M × D6 (Note 2) 37.8 parts by weight Nylon 6/66/610 (Note 3) 10.0 parts by weight Br- (Polyisobutylene-p-methylstyrene) (Note 4) 27.0 parts by mass (Note 1) “CM4061” manufactured by Toray Industries, Inc.
(Note 2) “Lenny 6002” manufactured by Mitsubishi Gas Chemical Company, Inc.
(Note 3) “CM4001” manufactured by Toray Industries, Inc.
(Note 4) “EXXPRO89-4” manufactured by Exxon Chemical.

<Comparative Examples 4-5>
A pneumatic tire was manufactured in the same manner as in Example 1 except that the distance L was changed to 1.5 + D / 2 or 2.0 + D / 2. Comparative examples 4 and 5 are examples in which the distance L exceeds 1 + D / 2. Here, the cord diameter (D) is 0.7 mm.

(performance test)
The following performance tests were conducted on the polymer laminates or polymer films produced in Examples and Comparative Examples, or the produced pneumatic tires. The test results are shown in Tables 1 and 2.

(1) Peeling force test A polymer laminate or polymer film and a carcass rubber sheet (components: natural rubber and SBR) are vulcanized by heating under pressure at 170 ° C. for 12 minutes, and a peeling test. A piece was made. The polymer laminate was laminated so that the second layer (SIS layer or SIB layer or the like) was in contact with the rubber sheet. Using the obtained test piece, a peel test is performed in accordance with JIS K 6256 “Vulcanized rubber and thermoplastic rubber—How to determine adhesiveness” to determine the peel force (adhesive force) between the inner liner and the carcass ply. It was measured. The size of the test piece was 25 mm wide, and the peel test was performed at room temperature of 23 ° C. Based on the peel force of Comparative Example 1, the following formula:
Peeling force index = (Peeling force of each example and comparative example) / (Peeling force of comparative example 1) × 100
Based on the above, the peel force of each example and comparative example was displayed as an index. It shows that the peeling force (adhesive force) between an inner liner and a carcass ply is so large that a peeling force index | exponent is large. The larger the peel force (adhesive force) between the inner liner and the carcass ply, the better.

(2) Bending fatigue test In accordance with JIS K 6260 “De-mature bending crack test method for vulcanized rubber and thermoplastic rubber”, a polymer laminate or polymer film is attached to rubber and vulcanized, and a groove is formed in the center. A predetermined test piece was produced. An incision was made in advance at the center of the groove of the test piece, and a test was conducted to measure crack growth by repeatedly bending and deforming. Specifically, the crack length was measured at 700,000, 1.4, and 2.1 million times at an ambient temperature of 23 ° C., a strain of 30%, and a period of 5 Hz, and repeated bending deformation required for the crack to grow 1 mm. The number of times was calculated. Based on the number of repetitions of Comparative Example 1, the following formula:
Bending fatigue resistance index = (number of repetitions of each example and comparative example) / (number of repetitions of comparative example 1) × 100
Based on the above, the bending fatigue resistance of each example and comparative example was expressed as an index. The larger the bending fatigue resistance index, the better the cracks are less likely to grow.

(3) Static air pressure drop rate test (tire air leak test)
The tires of the examples and comparative examples (195 / 65R15 steel radial PC tires) manufactured by the above-described method were assembled in a JIS standard rim 15 × 6JJ, sealed with an initial air pressure of 300 Kpa, left at room temperature for 90 days, and the air pressure decreased. The rate was calculated and the rate of decrease in air pressure per month (30 days) (unit:% / month) was calculated. The smaller the static air pressure reduction rate, the better.

(4) Steering stability test The pneumatic tires of each of the examples and comparative examples were mounted on all wheels of a vehicle (domestic FF car 2000cc) and run on the test course, and the steering stability was evaluated by sensory evaluation of the driver. . Relative evaluation was performed with 10 points being a perfect score and the steering stability of Comparative Example 1 being 6 points. The larger the value, the better the steering stability.

(5) Inner liner weight measurement test Based on the weight of the inner liner (polymer film A) of Comparative Example 1, the following formula:
Inner liner weight index = (inner liner weight of each example and comparative example) / (inner liner weight of comparative example 1) × 100
Based on the above, the weight of the inner liner of each example and comparative example was indicated by an index. It shows that the achievement degree of weight reduction is so high that an inner liner weight index is small.

(Performance evaluation results)
In Examples 1 to 3, a polymer laminate including an SIBS layer (thickness 0.5 mm) as the first layer and an SIB layer (thickness 0.1 mm) as the second layer was used for the inner liner. In Examples 4 to 6, a polymer laminate including an SIBS layer (thickness 0.5 mm) as the first layer and an SIS layer (thickness 0.1 mm) as the second layer was used for the inner liner. In any of the examples, the inner liner is thinner than the comparative example 1 made of the conventional rubber composition for the inner liner, but is excellent in bending fatigue resistance and static air pressure reduction rate while maintaining the same peeling force. In addition, the steering stability was excellent. In Comparative Examples 4 and 5 having a large distance L, the steering stability was lowered.

  In Examples 7 to 11, a polymer laminate including an SIBS layer (thickness 0.05 to 0.5 mm) as a first layer and an SIB layer (thickness 0.01 to 0.30 mm) as a second layer is used. Using. In any of the examples, although the inner liner is thinner than the comparative example 1 made of the conventional rubber composition for an inner liner, the bending fatigue resistance and the static air pressure drop are maintained while maintaining the same peeling force. The rate was excellent. Furthermore, the steering stability was excellent. Further, in Examples 10 and 11, the inner liner has a very thin configuration, and a significant weight reduction of the pneumatic tire can be achieved.

  In Comparative Example 1, an inner liner was produced using a conventional rubber composition for an inner liner including natural rubber and butyl rubber, and used as a reference. Comparative Example 2 is an example in which a polymer film consisting only of a SIBS layer (thickness 0.6 mm) was used as the inner liner. The bending fatigue resistance and static air pressure reduction rate were good, but the peel force was greatly inferior. Comparative Example 3 is an example in which a conventional polymer film (thickness: 0.6 mm) mainly composed of nylon is used as the inner liner. The static air pressure drop rate and steering stability were good, but the peel force and bending fatigue resistance were poor.

  Next, in order to verify the effect of adding EVOH, pneumatic tires of Examples 12 to 24 and Comparative Examples 6 to 9 having configurations shown in Tables 3 and 4 were manufactured, and performances were evaluated.

<Example 12>
As the polymer forming the first layer, the same SIBS used in Example 1 and an ethylene-vinyl alcohol copolymer (EVOH) [“Eval E105” manufactured by Kuraray Co., Ltd., represented by the above general formula (I)] Ethylene-vinyl alcohol copolymer, ethylene component content = 44 mol%. In the mass ratio of 85/15 (SIBS / EVOH), and the same SIB as used in Example 1 was used as the polymer for forming the second layer. An unvulcanized polymer laminate was produced in the same manner as in Example 1, and a pneumatic tire was produced in the same manner as in Example 1. The distance L was 0 mm. The thicknesses of the first layer and the second layer of the inner liner in the obtained pneumatic tire were 0.5 mm and 0.1 mm, respectively.

  The composition of the rubber composition used for the rubber layer of the carcass ply is the same as in Example 1. As in Example 1, polyester 1670 dtex having a diameter (D) of 0.7 mm was used for the cord of the carcass ply.

<Examples 13-24, Comparative Examples 6-9>
Tables 3 and 4 show the SIBS / EVOH mass ratio in the first layer, the type of copolymer constituting the second layer, the thickness of the first layer or the second layer, the distance L, or the configuration of the inner liner. A pneumatic tire was manufactured in the same manner as in Example 1 except that the change was made as described above. Table 3 also shows the data of Example 1 for reference. Comparative Examples 6 and 7 are the same as Comparative Examples 1 and 2 except that the distance L is 0 mm.

(performance test)
Peeling force test, flexural fatigue test, static air pressure drop rate test, steering stability test, adhesion test and inner liner for polymer laminates or polymer films prepared in Examples and Comparative Examples, or manufactured pneumatic tires A gravimetric test was performed. The standards for the peel strength index, the bending fatigue resistance index, and the inner liner weight index are Comparative Example 6. The test results are shown in Tables 3 and 4. Test methods for performance tests other than the adhesion test are as described above.

The tack test was performed according to the following procedure. According to JIS T 9233, using a Pikuma tack tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under the conditions of a measurement temperature of 23 ° C., a load of 4.9 N, a standing time of 10 seconds, and a peeling speed of 30 mm / min. The adhesive strength (N) of the rubber composition forming the inner liner (first layer in the case of a polymer laminate) was measured. Based on the adhesive strength of Comparative Example 6, the following formula:
Adhesive strength index = (adhesive strength of each example and comparative example) / (adhesive strength of comparative example 6) × 100
Based on the above, the adhesive strength of each Example and Comparative Example was displayed as an index. The larger the adhesive index, the higher the adhesive strength of the inner liner (or the first layer of the polymer laminate) and the better the processability of the pneumatic tire.

(Performance evaluation results)
In Examples 12 to 17, a polymer laminate including a SIBS / EVOH layer (thickness 0.5 mm) as a first layer and a SIB layer (thickness 0.1 mm) as a second layer was used for the inner liner. . In Examples 18 to 20, a polymer laminate composed of a SIBS / EVOH layer (thickness 0.5 mm) as the first layer and a SIS layer (thickness 0.1 mm) as the second layer was used for the inner liner. . In any of the examples, the inner liner is thinner than the comparative example 6 made of the conventional rubber composition for an inner liner, but maintains a sufficient bending fatigue resistance and adhesive force, while maintaining a peeling force, a static force. Excellent air pressure reduction rate and handling stability. Moreover, compared with Example 1 which does not use EVOH, the peeling force, the static air pressure reduction rate, and the adhesive force improved. However, when the EVOH content exceeded 30% by mass, the bending fatigue resistance decreased. In Comparative Examples 8 and 9 having a large distance L, the steering stability was lowered.

  In Examples 21 to 24, a polymer laminate composed of a SIBS / EVOH layer (thickness 0.05 to 0.5 mm) as a first layer and a SIB layer (thickness 0.01 to 0.30 mm) as a second layer Using the body. In any of the examples, the inner liner maintains a sufficient peeling force, bending fatigue resistance, steering stability, and adhesive strength even though it is thinner than the comparative example 6 made of a conventional rubber composition for an inner liner. While the static air pressure drop rate was excellent. Moreover, compared with Example 1 which does not use EVOH, the static air pressure fall rate and the adhesive force improved. In Examples 23 and 24, the inner liner has a very thin configuration, and a significant weight reduction of the pneumatic tire can be achieved.

  Next, in order to verify the addition effect of the organically treated clay mineral, the pneumatic tires of Examples 25 to 40 and Comparative Examples 10 to 11 having the configurations shown in Tables 5 and 6 were manufactured, and the performance was evaluated. did.

<Example 25>
As the polymer forming the first layer, the same SIBS used in Example 1 and an organically treated clay mineral [“BENTONE 34” manufactured by Pheox (layered clay mineral: hectorite viscosity mineral, organic compound: dimethyl distearyl ammonium) Salt, organic compound cation exchange amount: 100 meg / 100 g)] in a mass ratio of 100/30 (SIBS / organized clay mineral), and polymer forming the second layer As in Example 1, an unvulcanized polymer laminate was produced in the same manner as in Example 1, and a pneumatic tire was produced in the same manner as in Example 1. The distance L was 0 mm. The thicknesses of the first layer and the second layer of the inner liner in the obtained pneumatic tire were 0.5 mm and 0.1 mm, respectively.

  The composition of the rubber composition used for the rubber layer of the carcass ply is the same as in Example 1. As in Example 1, polyester 1670 dtex having a diameter (D) of 0.7 mm was used for the cord of the carcass ply.

<Examples 26 to 40, Comparative Examples 10 to 11>
Tables 5 and 6 show the SIBS / organized clay mineral mass ratio in the first layer, the type of copolymer constituting the second layer, the thickness of the first or second layer, the distance L, and the like. A pneumatic tire was manufactured in the same manner as in Example 1 except that the change was made as described above. In Table 5, the data of Example 1 and Comparative Examples 6 and 7 are also shown for reference. The mass parts of the clay mineral in Tables 5 and 6 are values with respect to 100 parts by mass of SIBS. Further, the inorganic clay mineral used in Examples 29 and 30 is “Kunipia F” manufactured by Kunimine Kogyo Co., Ltd.

(performance test)
For the polymer laminates or polymer films produced in the examples and comparative examples, or the manufactured pneumatic tires, a peel force test, a bending fatigue test, a static air pressure reduction rate test, a steering stability test, and an inner liner weight measurement test were conducted. went. Test methods for performance tests other than the steering stability test are as described above. The standards for the peel strength index, the bending fatigue resistance index, and the inner liner weight index are Comparative Example 6. The test results are shown in Tables 5 and 6. Regarding the steering stability test, as the vehicle in the above-described steering stability test, a domestic FF vehicle, 1800 cc, vehicle weight about 1200 kg (steering stability test A), a domestic FF vehicle, 1,800 cc, vehicle weight about 1500 kg (maneuvering stability) Two tests with test B) were performed (steering stability A, B in Tables 5 and 6).

(Performance evaluation results)
In Examples 25-28 and 31-36, the SIBS / organized clay mineral layer (thickness 0.5 mm) as the first layer and the SIB layer or SIS layer (thickness 0) as the second layer were formed on the inner liner. .1 mm) was used. In any of the examples, the inner liner was excellent in steering stability A and B although it was thinner than the comparative example 6 made of the conventional rubber composition for an inner liner. In addition, steering stability A and / or B was improved as compared with Example 1 in which no organically treated clay mineral was used. However, when the content of the organically treated clay mineral exceeded 50 parts by mass with respect to 100 parts by mass of SIBS, the bending fatigue resistance and the static air pressure reduction rate decreased. Also, when an inorganic clay mineral was used as the clay mineral, the bending fatigue resistance and the static air pressure reduction rate were reduced. In Comparative Examples 10 and 11 having a large distance L, the steering stability A and / or B was lowered.

  In Examples 37 to 40, the SIBS / organized clay mineral layer (thickness 0.05 to 0.5 mm) as the first layer and the SIB layer (thickness 0.01 to 0.30 mm) as the second layer A polymer laminate comprising: In any of the examples, the inner liner maintains a sufficient peeling force, bending fatigue resistance, and static air pressure reduction rate despite being thinner than the comparative example 6 made of the conventional rubber composition for an inner liner. However, the steering stability A and B were excellent. In addition, steering stability A and B was improved as compared with Example 1 in which no organically treated clay mineral was used. In Examples 39 and 40, the inner liner has a very thin configuration, and a significant weight reduction of the pneumatic tire can be achieved.

  Next, in order to verify the addition effect of the tackifier, the pneumatic tires of Examples 41 to 64 and Comparative Example 12 having the configurations shown in Tables 7 to 9 were manufactured, and the performance was evaluated.

<Example 41>
As a polymer for forming the first layer, a rubber composition obtained by mixing the same SIBS used in Example 1 and a tackifier A at a mass ratio of 100/1 (SIBS / tackifier A) is used. Further, as the polymer for forming the second layer, a rubber composition in which the same SIB and SIBS as used in Example 1 were mixed at a mass ratio of 90/10 was used, and unvulcanized in the same manner as in Example 1. A polymer laminate was produced, and a pneumatic tire was produced in the same manner as in Example 1. The distance L was 0 mm. The thicknesses of the first layer and the second layer of the inner liner in the obtained pneumatic tire were 0.5 mm and 0.1 mm, respectively.

  The composition of the rubber composition used for the rubber layer of the carcass ply is the same as in Example 1. As in Example 1, polyester 1670 dtex having a diameter (D) of 0.7 mm was used for the cord of the carcass ply.

<Examples 42 to 64, Comparative Example 12>
Mass ratio of SIBS / tackifier in the first layer or second layer, type of tackifier, type and mixing ratio of copolymer constituting the second layer, thickness of first layer or second layer, distance A pneumatic tire was manufactured in the same manner as in Example 1 except that L and the like were changed as shown in Tables 7 to 9. Table 7 shows the data of Example 1 and Comparative Examples 6 and 7 together for reference. The mass parts of the tackifier in Tables 7 to 9 are values for 100 parts by mass of SIBS for the first layer and 100 parts by mass of the total amount of SIS or SIB and SIBS for the second layer. The tackifiers A to C in Tables 7 to 9 are as follows.

(1) Tackifier A: C9 petroleum resin, Alcon P140 (Arakawa Chemical Industries, Ltd., softening point: 140 ° C., weight average molecular weight: 900),
(2) Tackifier B: terpene resin, YS resin PX1250 (manufactured by Yashara Chemical Co., Ltd., softening point: 125 ° C., weight average molecular weight: 700),
(3) Tackifier C: hydrogenated rosin ester, super ester A125 (Arakawa Chemical Industries, softening point: 125 ° C., weight average molecular weight: 700).

(performance test)
For polymer laminates or polymer films produced in Examples and Comparative Examples, or produced pneumatic tires, peel strength test, flexural fatigue test, static air pressure drop rate test, steering stability test, adhesion test and inner liner A gravimetric test was performed. The test method is as described above. The standards of the peel strength index, the bending fatigue resistance index, the adhesive strength index, and the inner liner weight index are Comparative Example 6. The test results are shown in Tables 7-9.

(Performance evaluation results)
In Examples 41 to 64, although the inner liner was thinner than Comparative Example 6 made of a conventional rubber composition for an inner liner, in many cases, the peel strength and the bending fatigue resistance were maintained while maintaining sufficient adhesive strength. , Static air pressure drop rate and steering stability improved. Further, in many cases, the peel strength, the bending fatigue resistance, the static air pressure reduction rate and the adhesive strength were improved as compared with Example 1 in which no tackifier was used. However, when the content of the tackifier exceeded 100 parts by mass, the static air pressure reduction rate and the steering stability were lowered, and the adhesive strength was excessively increased. Moreover, when content of SIBS which comprises a 2nd layer became high to 90 mass%, peeling force fell.

  Examples 62 to 64 are examples in which the thickness of the inner liner was further reduced, but excellent tire performance was also obtained in these examples. In Comparative Example 12 having a large distance L, the steering stability was lowered.

  The pneumatic tire of the present invention can be used as a pneumatic tire for trucks and buses, heavy machinery, etc. in addition to a pneumatic tire for passenger cars.

  DESCRIPTION OF SYMBOLS 1 Pneumatic tire, 2 tread part, 3 side wall part, 4 bead part, 5 bead core, 6,61 carcass ply, 6a rubber layer, 7 belt layer, 8 bead apex, 9 inner liner, 10 polymer laminated body, 11 SIBS Layer, 12 SIS layer, 13 SIB layer, IL1 first layer, IL2 second layer, S interface between the rubber layer constituting the carcass ply and the second layer of the inner liner, K carcass ply cord, cross section of KC cord The plane passing through the center, the diameter of the D code, and the distance from the plane passing through the center of the cross section of the L code to the second layer.

Claims (12)

A pneumatic tire comprising an inner liner disposed inside a tire, and a carcass ply provided adjacent to the inner liner and having a cord embedded in a rubber layer,
The inner liner includes a styrene-isobutylene-styrene triblock copolymer, a first layer having a thickness of 0.05 mm to 0.6 mm, a styrene-isobutylene diblock copolymer, and a thickness of 0. Composed of a polymer laminate composed of a second layer of .01 mm to 0.3 mm,
The second layer is disposed in contact with the rubber layer of the carcass ply,
A pneumatic tire in which a distance L from the surface passing through the center of the cross section of the cord to the second layer is 0 or more and (1 + D / 2) mm or less when the diameter of the cord is D.   The pneumatic tire according to claim 1, wherein the first layer is made of a styrene-isobutylene-styrene triblock copolymer.   The pneumatic tire according to claim 1, wherein the first layer is composed of 99 to 70% by mass of a styrene-isobutylene-styrene triblock copolymer and 1 to 30% by mass of an ethylene-vinyl alcohol copolymer.   The pneumatic tire according to claim 3, wherein the ethylene-vinyl alcohol copolymer has an ethylene component content of 25 to 50 mol%.   2. The first layer according to claim 1, wherein the first layer further includes 0.1 to 50 parts by mass of a layered clay mineral in which an organic compound is intercalated with respect to 100 parts by mass of a styrene-isobutylene-styrene triblock copolymer. Pneumatic tire. The first layer has a weight average molecular weight of 1 × 10 ² to 1 × 10 ⁶ and a softening point of 50 ° C. to 150 ° C. with respect to 100 parts by mass of a styrene-isobutylene-styrene triblock copolymer. Further comprising 1 to 100 parts by weight of an imparting agent,
The pneumatic tire according to claim 1, wherein the second layer includes 20 to 90 mass% of a styrene-isobutylene diblock copolymer and 10 to 80 mass% of a styrene-isobutylene-styrene triblock copolymer. The second layer has a weight average molecular weight of 1 × 10 ² to 1 × 10 ⁶ with respect to 100 parts by mass of the total amount of the styrene-isobutylene diblock copolymer and the styrene-isobutylene-styrene triblock copolymer. The pneumatic tire according to claim 6, further comprising 1 to 100 parts by mass of a tackifier having a softening point of 50C to 150C.   The pneumatic tire according to any one of claims 1 to 7, wherein the styrene-isobutylene-styrene triblock copolymer has a styrene component content of 10 to 30% by mass. The pneumatic tire according to any one of claims 1 to 5, wherein the second layer further includes a styrene-isoprene-styrene triblock copolymer.   The pneumatic tire according to claim 9, wherein the styrene-isoprene-styrene triblock copolymer has a styrene component content of 10 to 30% by mass and a weight average molecular weight of 100,000 to 290,000.   The styrene-isobutylene diblock copolymer is linear, has a styrene component content of 10 to 35 mass%, and has a weight average molecular weight of 40,000 to 120,000. The pneumatic tire according to Crab.   The pneumatic tire according to claim 1, wherein a boundary surface between the polymer laminate constituting the inner liner and a rubber layer of the carcass ply forms an uneven shape.

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