JP6125764B2 - Inner liner and pneumatic tire - Google Patents

Description

  The present invention relates to an inner liner and a pneumatic tire, and more particularly to an inner liner and a pneumatic tire that can be joined to a tire inner surface without providing an adhesive layer.

  Conventionally, a rubber composition mainly composed of butyl rubber, halogenated butyl rubber or the like is used for an inner liner disposed as an air barrier layer on the tire inner surface in order to maintain the internal pressure of the tire. However, these rubber compositions using butyl rubber as the main raw material have low air barrier properties, so when such a rubber composition is used for the inner liner, the thickness of the inner liner has to be about 1 mm. Therefore, the weight of the inner liner in the tire is about 5%, which is an obstacle to improving the fuel efficiency of automobiles, agricultural vehicles, construction vehicles, etc. by reducing the weight of the tires.

  On the other hand, an ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as EVOH) is known to have excellent gas barrier properties. Since the EVOH has an air permeation amount of 1/100 or less of the above butyl rubber composition for an inner liner, even if the thickness is 100 μm or less, the internal pressure retention of the tire can be greatly improved. It is possible to reduce the weight of the tire.

  There are many resins that have lower air permeability than the butyl rubber, but if the air permeability is about 1/10 of the butyl inner liner, the internal pressure retention effect can be improved unless the thickness exceeds 100 μm. If the thickness is less than 100 μm, the effect of reducing the weight of the tire is small, and the inner liner breaks due to deformation at the time of bending of the tire, or cracks occur in the inner liner, resulting in barrier properties. It becomes difficult to hold. In order to improve the bending resistance, a technique of using an elastomer containing a halide of isobutylene paramethylstyrene copolymer for a nylon resin having a melting point of 170 to 230 ° C. is disclosed (Patent Document 1). Since the ratio of the elastomer is high, there is a problem that although the bending resistance is improved, the barrier property of the nylon resin cannot be maintained.

  On the other hand, when the EVOH is used, it can be used even with a thickness of 100 μm or less, so that it is difficult to break due to bending deformation at the time of rolling of the tire, and cracks are hardly generated. Therefore, it can be said that it is effective to use EVOH for the inner liner of the tire in order to improve the internal pressure retention of the pneumatic tire. For example, Patent Document 2 discloses a pneumatic tire including an inner liner made of EVOH.

Moreover, in the inner liner disclosed in Patent Document 3, it is preferable that the inner liner is used by being bonded to an auxiliary layer made of an elastomer via an adhesive layer in order to improve the internal pressure retention of the tire.
However, since the adhesiveness between the resin film layer containing the thermoplastic resin and the rubber-like elastic body layer is low, there is room for improvement in the peeling effect.

  Therefore, in Patent Document 4, for the purpose of improving the peeling effect, the maleimide derivative (H) having two or more reactive sites in the molecule and the poly-p-dinitroso with respect to 100 parts by mass of the rubber component in the adhesive layer. There is disclosed a laminate comprising an adhesive composition (I) containing 0.1 part by mass or more of at least one kind of benzene.

JP-A-11-199713 JP-A-6-40207 JP 2004-176048 A JP 2008-24228 A

  Here, with respect to the techniques of the cited references 1 to 4, it was necessary to provide an adhesive layer in order to join the inner liner to the inner surface of the pneumatic tire, but the volatile organic compound contained in the adhesive ( It is preferable to eliminate the VOC), and further, from the point of eliminating the complexity of the adhesive coating process, the development of an inner liner that can be bonded to the inner surface of a pneumatic tire without providing an adhesive layer has been developed. It is desired.

  Therefore, an object of the present invention is to provide an inner liner having an excellent adhesion to the tire inner surface without providing an adhesive layer, and a pneumatic tire using the inner liner.

  In order to solve the above-mentioned problems, the present inventors have intensively studied to solve the above-mentioned problems with an inner liner for a tire including a laminate in which an elastic layer containing a thermoplastic elastomer and a barrier layer containing a gas barrier resin are alternately laminated. As a result, the outermost surface layer outside the tire among the layers constituting the laminate is further provided with an outermost surface layer containing an elastomer component that can be heat-bonded to the diene rubber, whereby the adhesive layer The present inventors have found that an excellent adhesion force to the tire inner surface can be realized without providing a tire.

That is, the tire inner liner of the present invention is a tire inner liner comprising a laminate obtained by alternately laminating an elastic body layer containing a thermoplastic elastomer and a barrier layer containing a gas barrier resin. The outermost layer of at least one of the layers constituting the body contains an elastomer component that can be heat-bonded to a diene rubber, and the elastomer component is a polymer having a vulcanizable diene portion, and has a urethane bond It is characterized by having .

Furthermore, the elastomer component of the outermost surface layer is more preferably at least one of natural rubber, butadiene rubber, isoprene rubber, and styrene butadiene rubber.

  The outermost surface layer and the tire inner surface to be joined are preferably joined by vulcanization.

  The gas barrier resin of the barrier layer preferably has a hydroxy group, and the elastomer component of the outermost surface layer more preferably has a modifying group capable of binding to the hydroxy group of the gas barrier resin.

  Furthermore, the thermoplastic elastomer is preferably a polyurethane-based thermoplastic elastomer.

  Moreover, it is preferable that the inner liner of this invention is manufactured by coextrusion molding.

  And the pneumatic tire of this invention is equipped with the said inner liner, It is characterized by the above-mentioned.

  According to the laminate, the tire inner liner and the pneumatic tire of the present invention, it is possible to provide an inner liner having excellent adhesion to the tire inner surface and a pneumatic tire using the inner liner without providing an adhesive layer. .

It is typical sectional drawing which showed a part of inner liner of this invention. It is a fragmentary sectional view of one embodiment of the pneumatic tire of the present invention.

<Inner liner>
Below, the inner liner of this invention is demonstrated in detail, referring a figure.
FIG. 1 is a view of a cross section of the inner liner of the present invention.

As shown in FIG. 1, the inner liner of the present invention includes a laminate 1 in which elastic layers 3 containing a thermoplastic elastomer and barrier layers 4 containing a gas barrier resin are alternately laminated.
In the present invention, the outermost surface layer 2 located on the outermost side of the tire (in the direction of arrow A) among the layers 2, 3, and 4 constituting the laminate 1 is heat-bondable with the diene rubber. It contains an ingredient.

  By providing the above configuration, as shown in FIG. 1, when the inner liner 1 is joined to the inner surface 5 a of the pneumatic tire 5, the elastomer component in the outermost surface layer 2 is contained in the rubber component of the pneumatic tire 5. Therefore, it is possible to obtain a high adhesive force with the inner surface of the pneumatic tire without separately providing a layer made of an adhesive.

  Furthermore, the outermost surface layer can be formed together with the barrier layer and the elastic body layer, for example, by coextrusion molding, unlike the adhesive layer formed on the conventional inner liner. In comparison, the manufacturing process is also simplified.

(Barrier layer)
The barrier layer constituting the inner liner of the present invention is a layer containing a gas barrier resin in order to realize the air barrier property of the laminate and maintain the internal pressure of the tire.
Here, the gas barrier resin is not particularly limited as long as a desired air barrier property can be secured. For example, a polyamide resin, an ethylene-vinyl alcohol copolymer, a modified ethylene-vinyl alcohol copolymer can be used. Examples thereof include a polymer, a urethane polymer, an olefin polymer, and a diene polymer. Moreover, these resin may be used individually by 1 type, and may be used in combination of 2 or more type.
Moreover, it is preferable that the said gas barrier resin has a hydroxyl group from the point which can ensure high air barrier property.

  Further, among the above resins, an ethylene-vinyl alcohol copolymer, a modified ethylene-vinyl alcohol copolymer, or a polyamide-based resin is preferable. This is because such a resin has a low air permeation amount and excellent gas barrier properties.

  The ethylene-vinyl alcohol copolymer (EVOH) preferably has an ethylene content of 25 to 50 mol%, more preferably 30 to 48 mol%, and further preferably 35 to 45 mol%. preferable. If the ethylene content is less than 25 mol%, the bending resistance, fatigue resistance and melt moldability may be deteriorated. On the other hand, if it exceeds 50 mol%, the gas barrier properties may not be sufficiently secured. The ethylene-vinyl alcohol copolymer preferably has a saponification degree of 90% or more, more preferably 95% or more, and still more preferably 99% or more. If the degree of saponification is less than 90%, gas barrier properties and thermal stability during molding may be insufficient. Further, the ethylene-vinyl alcohol copolymer preferably has a melt flow rate (MFR) of 0.1 to 30 g / 10 minutes under a load of 2160 g at 190 ° C., more preferably 0.3 to 25 g / 10 minutes. .

  The ethylene-vinyl alcohol copolymer preferably has an ethylene content of 3 to 70 mol%, from 10 to 60 mol%, from the viewpoint of improving gas barrier properties, melt moldability and interlayer adhesion of the inner liner. More preferably, it is more preferably 20 to 55 mol%, particularly preferably 25 to 50 mol%. If the ethylene content is less than 3 mol%, the water resistance, hot water resistance, gas barrier properties and melt moldability under high humidity may be deteriorated. On the other hand, if the ethylene content exceeds 70 mol%, the gas barrier of the inner liner may be reduced. May decrease.

  The ethylene-vinyl alcohol copolymer preferably has a saponification degree of 80% or more, more preferably 90% or more, from the viewpoint of improving gas barrier properties, moisture resistance and interlayer adhesion of the inner liner. Is more preferably 95% or more, and particularly preferably 99% or more. On the other hand, the saponification degree of the ethylene-vinyl alcohol copolymer is preferably 99.99% or less. If the saponification degree of EVOH is less than 80%, the melt moldability, gas barrier properties, coloration resistance and moisture resistance of the inner liner may be lowered.

  The ethylene-vinyl alcohol copolymer has a melt flow rate (MFR) of 0.1 to 30 g / 10 min at 190 ° C. and a load of 21.18 N from the viewpoint of obtaining gas barrier properties, flex resistance and fatigue resistance. Preferably, it is 0.3-25 g / 10min.

The ethylene-vinyl alcohol copolymer has a content G (mol%) of 1,2-glycol bond structural units of the following formula:
G ≦ 1.58−0.0244 × E
[Wherein, G is the content (mol%) of 1,2-glycol bond structural unit, E is the ethylene unit content (mol%) in EVOH, where E ≦ 64) And the intrinsic viscosity is preferably in the range of 0.05 to 0.2 L / g. By using such EVOH, the obtained inner liner is less dependent on the humidity of the gas barrier property, has good transparency and gloss, and can be easily laminated on a layer made of another resin. The content of the 1,2-glycol-bonded structural unit was determined by changing the EVOH sample to a dimethyl sulfoxide solution according to the method described in “S. Aniya et al., Analytical Science Vol. 1, 91 (1985)”. It can be measured by nuclear magnetic resonance at 90 ° C.

  The modified ethylene-vinyl alcohol copolymer has, in addition to ethylene units and vinyl alcohol units, other repeating units (hereinafter also referred to as structural units), for example, one or more kinds of repeating units derived from these units. It is a polymer. The preferred ethylene content, degree of saponification, melt flow rate (MFR), content of 1,2-glycol bond structural unit and intrinsic viscosity of the modified EVOH are the same as those of the above-mentioned EVOH.

上記式（Ｉ）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立して、水素原子、炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基、炭素数６〜１０の芳香族炭化水素基又はヒドロキシ基を表す。また、Ｒ^１、Ｒ^２及びＲ^３のうちの一対が結合していてもよい（但し、Ｒ^１、Ｒ^２及びＲ^３のうちの一対が共に水素原子の場合は除く）。また、前記炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基は、ヒドロキシ基、カルボキシ基又はハロゲン原子を有していてもよい。一方、上記式（ＩＩ）中、Ｒ^４、Ｒ^５、Ｒ^６及びＲ^７は、それぞれ独立して、水素原子、炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基、炭素数６〜１０の芳香族炭化水素基又はヒドロキシ基を表す。また、Ｒ^４とＲ^５又はＲ^６とＲ^７は結合していてもよい（但し、Ｒ^４とＲ^５又はＲ^６とＲ^７が共に水素原子の場合は除く）。また、前記炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基は、ヒドロキシ基、アルコキシ基、カルボキシ基又はハロゲン原子を有していてもよい。 The modified EVOH preferably has, for example, at least one structural unit selected from the structural units (I) and (II) shown below, and the structural unit is 0.5 to 30 mol% based on the total structural units. More preferably, it is contained in a proportion. Such a modified EVOH can improve the flexibility and processing characteristics of the resin or resin composition, and the interlayer adhesion, stretchability, and thermoformability of the inner liner.

In the above formula (I), R ¹ , R ² and R ³ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, An aromatic hydrocarbon group or hydroxy group having 6 to 10 carbon atoms is represented. In addition, a pair of R ¹ , R ² and R ³ may be bonded (except when a pair of R ¹ , R ² and R ³ are both hydrogen atoms). The aliphatic hydrocarbon group having 1 to 10 carbon atoms, the alicyclic hydrocarbon group having 3 to 10 carbon atoms, or the aromatic hydrocarbon group having 6 to 10 carbon atoms includes a hydroxy group, a carboxy group, or a halogen atom. You may have. On the other hand, in said formula (II), R < ⁴ >, R < ⁵ >, R < ⁶ > and R <^7> are respectively independently a hydrogen atom, a C1-C10 aliphatic hydrocarbon group, and a C3-C10 alicyclic ring. A formula hydrocarbon group, a C6-C10 aromatic hydrocarbon group, or a hydroxy group is represented. R ⁴ and R ⁵ or R ⁶ and R ⁷ may be bonded to each other (except when R ⁴ and R ⁵ or R ⁶ and R ⁷ are both hydrogen atoms). Moreover, the said C1-C10 aliphatic hydrocarbon group, a C3-C10 alicyclic hydrocarbon group, or a C6-C10 aromatic hydrocarbon group is a hydroxy group, an alkoxy group, a carboxy group, or It may have a halogen atom.

  In the modified EVOH, the lower limit of the content of the structural unit (I) and / or (II) with respect to all the structural units is preferably 0.5 mol%, more preferably 1 mol%, and even more preferably 1.5 mol%. On the other hand, in the modified EVOH, the upper limit of the content of the structural unit (I) and / or (II) with respect to all the structural units is preferably 30 mol%, more preferably 15 mol%, still more preferably 10 mol%. By containing the structural units (I) and / or (II) in the specified proportions, the flexibility and processing characteristics of the resin or resin composition, and the interlayer adhesion, stretchability and thermoformability of the inner liner can be achieved. Can be improved.

  In the structural units (I) and (II), examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include an alkyl group and an alkenyl group, and examples of the alicyclic hydrocarbon group having 3 to 10 carbon atoms include cyclohexane. An alkyl group, a cycloalkenyl group, etc. are mentioned, A phenyl group etc. are mentioned as a C6-C10 aromatic hydrocarbon group.

In the structural unit (I), R ¹ , R ² and R ³ are preferably each independently a hydrogen atom, a methyl group, an ethyl group, a hydroxy group, a hydroxymethyl group or a hydroxyethyl group. Among these, a hydrogen atom, a methyl group, a hydroxy group, or a hydroxymethyl group is more preferable. With such R ¹ , R ² and R ³ , the stretchability and thermoformability of the inner liner can be further improved.

  The method for incorporating the structural unit (I) in EVOH is not particularly limited. For example, in the copolymerization of ethylene and vinyl ester, a monomer further derived into the structural unit (I). And the like. Examples of the monomer derived from the structural unit (I) include alkene such as propylene, butylene, pentene, hexene; 3-hydroxy-1-propene, 3-acyloxy-1-propene, 3-acyloxy-1 -Butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-hydroxy-1-butene, 4-acyloxy-3-hydroxy-1-butene, 3-acyloxy-4 -Methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4-hydroxy-1 -Pentene, 5-hydroxy-1-pentene, 4,5-dihydroxy-1-pentene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, , 5-diacyloxy-1-pentene, 4-hydroxy-3-methyl-1-pentene, 5-hydroxy-3-methyl-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 5,6 -Dihydroxy-1-hexene, 4-hydroxy-1-hexene, 5-hydroxy-1-hexene, 6-hydroxy-1-hexene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy Alkenes having a hydroxy group or an ester group such as -1-hexene and 5,6-diacyloxy-1-hexene are exemplified. Among these, from the viewpoint of copolymerization reactivity and gas barrier properties of the resulting inner liner, propylene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, and 3, 4-diacetoxy-1-butene is preferred. Specifically, propylene, 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene, and 3,4-diacetoxy-1-butene are more preferable, and 3,4-diacetoxy- 1-butene is particularly preferred. In addition, when using the alkene which has ester, it is induced | guided | derived to the said structural unit (I) in the case of saponification reaction.

In the structural unit (II), R ⁴ and R ⁵ are preferably both hydrogen atoms. In particular, it is more preferable that R ⁴ and R ⁵ are both hydrogen atoms, one of the R ⁶ and R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and the other is a hydrogen atom. The aliphatic hydrocarbon group in the structural unit (II) is preferably an alkyl group or an alkenyl group. Further, from the viewpoint of particularly emphasizing the gas barrier property of the inner liner, it is preferable that one of R ⁶ and R ⁷ is a methyl group or an ethyl group, and the other is a hydrogen atom. Furthermore, it is also preferable that one of R ⁶ and R ⁷ is a substituent represented by (CH ₂ ) _h OH (where h is an integer of 1 to 8) and the other is a hydrogen atom. In the substituent represented by (CH ₂ ) _h OH, h is preferably an integer of 1 to 4, more preferably 1 or 2, and particularly preferably 1.

上記式（ＩＩＩ）〜（ＩＸ）中、Ｒ^８、Ｒ^９、Ｒ^１０、Ｒ^１１及びＲ^１２は、水素原子、炭素数１〜１０の脂肪族炭化水素基（アルキル基又はアルケニル基等）、炭素数３〜１０の脂環式炭化水素基（シクロアルキル基又はシクロアルケニル基等）又は炭素数６〜１０の芳香族炭化水素基（フェニル基等）を表す。なお、Ｒ^８及びＲ^９又はＲ^１１及びＲ^１２は、同一であってもよく、異なっていてもよい。また、ｉ、ｊ、ｋ、ｐ及びｑは、１〜８の整数を表す。 In addition, the method of incorporating the structural unit (II) in EVOH is not particularly limited, and examples thereof include a method of reacting a monovalent epoxy compound with EVOH obtained by a saponification reaction. Preferred examples of the monovalent epoxy compound include compounds represented by the following formulas (III) to (IX).

In the above formulas (III) to (IX), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms (such as an alkyl group or an alkenyl group), An alicyclic hydrocarbon group having 3 to 10 carbon atoms (such as a cycloalkyl group or a cycloalkenyl group) or an aromatic hydrocarbon group having 6 to 10 carbon atoms (such as a phenyl group) is represented. R ⁸ and R ⁹ or R ¹¹ and R ¹² may be the same or different. Moreover, i, j, k, p, and q represent the integer of 1-8.

  Examples of the monovalent epoxy compound represented by the formula (III) include epoxy ethane (ethylene oxide), epoxy propane, 1,2-epoxybutane, 2,3-epoxybutane, and 3-methyl-1,2- Epoxybutane, 1,2-epoxypentane, 2,3-epoxypentane, 3-methyl-1,2-epoxypentane, 4-methyl-1,2-epoxypentane, 4-methyl-2,3-epoxypentane, 3-ethyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxyhexane, 4-methyl-1,2 -Epoxyhexane, 5-methyl-1,2-epoxyhexane, 3-ethyl-1,2-epoxyhexane, 3-propyl-1,2-epoxy Xanthone, 4-ethyl-1,2-epoxyhexane, 5-methyl-1,2-epoxyhexane, 4-methyl-2,3-epoxyhexane, 4-ethyl-2,3-epoxyhexane, 2-methyl- 3,4-epoxyhexane, 2,5-dimethyl-3,4-epoxyhexane, 3-methyl-1,2-epoxyheptane, 4-methyl-1,2-epoxyhexane, 5-methyl-1,2- Epoxyheptane, 6-methyl-1,2-epoxyheptane, 3-ethyl-1,2-epoxyheptane, 3-propyl-1,2-epoxyheptane, 3-butyl-1,2-epoxyheptane, 4-ethyl -1,2-epoxyheptane, 4-propyl-1,2-epoxyheptane, 6-ethyl-1,2-epoxyheptane, 4-methyl-2,3-epoxyheptane, -Ethyl-2,3-epoxyheptane, 4-propyl-2,3-epoxyheptane, 2-methyl-3,4-epoxyheptane, 5-methyl-3,4-epoxyheptane, 5-ethyl-3,4 -Epoxyheptane, 2,5-dimethyl-3,4-epoxyheptane, 2-methyl-5-ethyl-3,4-epoxyheptane, 1,2-epoxyheptane, 2,3-epoxyheptane, 3,4- Epoxyheptane, 1,2-epoxyoctane, 2,3-epoxyoctane, 3,4-epoxyoctane, 4,5-epoxyoctane, 1,2-epoxynonane, 2,3-epoxynonane, 3,4-epoxy Nonane, 4,5-epoxynonane, 1,2-epoxydecane, 2,3-epoxydecane, 3,4-epoxydecane, 4,5-epoxydecane, 5,6- Epoxy decane, 1,2-epoxy undecane, 2,3-epoxy undecane, 3,4-epoxy undecane, 4,5-epoxy undecane, 5,6-epoxy undecane, 1,2-epoxy undecane, 2,3-epoxy Dodecane, 3,4-epoxydodecane, 4,5-epoxydodecane, 5,6-epoxydodecane, 6,7-epoxydodecane, epoxyethylbenzene, 1-phenyl-1,2-propane, 3-phenyl-1,2, -Epoxypropane, 1-phenyl-1,2-epoxybutane, 3-phenyl-1,2-epoxypentane, 4-phenyl-1,2-epoxypentane, 5-phenyl-1,2-epoxypentane, 1- Phenyl-1,2-epoxyhexane, 3-phenyl-1,2-epoxyhexane, 4-phenyl-1,2, Epoxyhexane, 5-phenyl-1,2-epoxy hexane, 6-phenyl-1,2-epoxy hexane, and the like.

  Examples of the monovalent epoxy compound represented by the above formula (IV) include methyl glycidyl ether, ethyl glycidyl ether, n-propyl glycidyl ether, isopropyl glycidyl ether, n-butyl glycidyl ether, isobutyl glycidyl ether, tert-butyl glycidyl. Ether, 1,2-epoxy-3-pentyloxypropane, 1,2-epoxy-3-hexyloxypropane, 1,2-epoxy-3-heptyloxypropane, 1,2-epoxy-4-phenoxybutane, , 2-epoxy-4-benzyloxybutane, 1,2-epoxy-5-methoxypentane, 1,2-epoxy-5-ethoxypentane, 1,2-epoxy-5-propoxypentane, 1,2-epoxy- 5-butoxypentane, 1,2-d Xyl-5-pentyloxypentane, 1,2-epoxy-5-hexyloxypentane, 1,2-epoxy-5-phenoxypentane, 1,2-epoxy-6-methoxyhexane, 1,2-epoxy-6 Ethoxyhexane, 1,2-epoxy-6-propoxyhexane, 1,2-epoxy-6-butoxyhexane, 1,2-epoxy-6-heptyloxyhexane, 1,2-epoxy-7-methoxyheptane, 1, 2-epoxy-7-ethoxyheptane, 1,2-epoxy-7-propoxyheptane, 1,2-epoxy-7-butoxyheptane, 1,2-epoxy-8-methoxyoctane, 1,2-epoxy-8- Ethoxyoctane, 1,2-epoxy-8-butoxyoctane, glycidol, 3,4-epoxy-1-butanol, 4, -Epoxy-1-pentanol, 5,6-epoxy-1-hexanol, 6,7-epoxy-1-heptanol, 7,8-epoxy-1-octanol, 8,9-epoxy-1-nonanol, 9, Examples include 10-epoxy-1-decanol, 10,11-epoxy-1-undecanol, and the like.

  Examples of the monovalent epoxy compound represented by the above formula (V) include ethylene glycol monoglycidyl ether, propanediol monoglycidyl ether, butanediol monoglycidyl ether, pentanediol monoglycidyl ether, hexanediol monoglycidyl ether, heptanediol. Examples thereof include monoglycidyl ether and octanediol monoglycidyl ether.

  Examples of the monovalent epoxy compound represented by the formula (VI) include 3- (2,3-epoxy) propoxy-1-propene, 4- (2,3-epoxy) propoxy-1-butene, 5- (2,3-epoxy) propoxy-1-pentene, 6- (2,3-epoxy) propoxy-1-hexene, 7- (2,3-epoxy) propoxy-1-heptene, 8- (2,3- Epoxy) propoxy-1-octene and the like.

  Examples of the monovalent epoxy compound represented by the formula (VII) include 3,4-epoxy-2-butanol, 2,3-epoxy-1-butanol, 3,4-epoxy-2-pentanol, 2 , 3-epoxy-1-pentanol, 1,2-epoxy-3-pentanol, 2,3-epoxy-4-methyl-1-pentanol, 2,3-epoxy-4,4-dimethyl-1- Pentanol, 2,3-epoxy-1-hexanol, 3,4-epoxy-2-hexanol, 4,5-epoxy-3-hexanol, 1,2-epoxy-3-hexanol, 2,3-epoxy-4 , 4-Dimethyl-1-hexanol, 2,3-epoxy-4,4-diethyl-1-hexanol, 2,3-epoxy-4-methyl-4-ethyl-1-hexanol, 3,4-epoxy -5-methyl-2-hexanol, 3,4-epoxy-5,5-dimethyl-2-hexanol, 3,4-epoxy-2-heptanol, 2,3-epoxy-1-heptanol, 4,5-epoxy -3-heptanol, 2,3-epoxy-4-heptanol, 1,2-epoxy-3-heptanol, 2,3-epoxy-1-octanol, 3,4-epoxy-2-octanol, 4,5-epoxy -3-octanol, 5,6-epoxy-4-octanol, 2,3-epoxy-4-octanol, 1,2-epoxy-3-octanol, 2,3-epoxy-1-nonanol, 3,4-epoxy 2-nonanol, 4,5-epoxy-3-nonanol, 5,6-epoxy-4-nonanol, 3,4-epoxy-5-nonanol, 2,3-epoxy Si-4-nonanol, 1,2-epoxy-3-nonanol, 2,3-epoxy-1-decanol, 3,4-epoxy-2-decanol, 4,5-epoxy-3-decanol, 5,6- Examples include epoxy-4-decanol, 6,7-epoxy-5-decanol, 3,4-epoxy-5-decanol, 2,3-epoxy-4-decanol, 1,2-epoxy-3-decanol and the like.

  Examples of the monovalent epoxy compound represented by the above formula (VIII) include 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,2-epoxycycloheptane, 1,2-epoxycyclooctane, , 2-epoxycyclononane, 1,2-epoxycyclodecane, 1,2-epoxycycloundecane, 1,2-epoxycyclododecane and the like.

  Examples of the monovalent epoxy compound represented by the above formula (IX) include 3,4-epoxycyclopentene, 3,4-epoxycyclohexene, 3,4-epoxycycloheptene, 3,4-epoxycyclooctene, 3 , 4-epoxycyclononene, 1,2-epoxycyclodecene, 1,2-epoxycycloundecene, 1,2-epoxycyclododecene, and the like.

  Among the monovalent epoxy compounds, epoxy compounds having 2 to 8 carbon atoms are preferable. In particular, from the viewpoint of easy handling of the compound and reactivity with respect to EVOH, the carbon number of the monovalent epoxy compound is more preferably 2 to 6, and further preferably 2 to 4. The monovalent epoxy compound is particularly preferably a compound represented by the formula (III) or (IV) among the compounds represented by these formulas. Specifically, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethane, and glycidol are preferable from the viewpoint of reactivity to EVOH and gas barrier properties of the resulting inner liner, and among these, epoxypropane And glycidol are particularly preferred.

  In the present invention, the ethylene-vinyl alcohol copolymer is obtained, for example, by polymerizing ethylene and a vinyl ester to obtain an ethylene-vinyl ester copolymer, and saponifying the ethylene-vinyl ester copolymer. . Further, as described above, the modified ethylene-vinyl alcohol copolymer is obtained by (1) copolymerizing a monomer derived from the structural unit (I) in the polymerization of ethylene and vinyl ester, or (2) It is obtained by reacting a monovalent epoxy compound with EVOH obtained by a saponification reaction. Here, the polymerization method of the ethylene-vinyl alcohol copolymer and the modified ethylene-vinyl alcohol copolymer is not particularly limited, and for example, any of solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization may be used. Moreover, any of a continuous type and a batch type may be sufficient.

  Examples of vinyl esters that can be used for the polymerization include vinyl fatty acid such as vinyl acetate, vinyl propionate, and vinyl pivalate.

  Moreover, when manufacturing a modified ethylene-vinyl alcohol copolymer, the monomer which can be copolymerized with these monomers other than ethylene and vinyl ester may be used preferably in a small amount. This copolymerizable monomer includes, in addition to the monomer derived from the above structural unit (I), other alkenes such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, and itaconic acid. Saturated carboxylic acid or its anhydride, salt, monoalkyl ester or dialkyl ester, etc .; Nitriles such as acrylonitrile and methacrylonitrile; Amides such as acrylamide and methacrylamide; Olefins such as vinyl sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid Sulfonic acid or a salt thereof; alkyl vinyl ethers, vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride and the like. A vinyl silane compound can also be used as a monomer, and the amount of the vinyl silane compound introduced into the copolymer is preferably 0.0002 mol% or more and 0.2 mol% or less. Examples of the vinylsilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, γ-methacryloyloxypropylmethoxysilane, and the like. Among these vinylsilane compounds, vinyltrimethoxysilane and vinyltriethoxysilane are preferable.

  The solvent that can be used for the polymerization is not particularly limited as long as it is an organic solvent that can dissolve ethylene, vinyl ester, and ethylene-vinyl ester copolymer. Specific examples include alcohols such as methanol, ethanol, propanol, n-butanol and tert-butanol; dimethyl sulfoxide and the like. Among these, methanol is particularly preferable because removal and separation after the reaction is easy.

  Examples of the initiator that can be used for the polymerization include 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvaleronitrile), and 2,2′-azobis- (4-methoxy). -2,4-dimethylvaleronitrile), 2,2'-azobis- (2-cyclopropylpropionitrile) and other azonitrile initiators; isobutyryl peroxide, cumylperoxyneodecanoate, diisopropylperoxycarbonate And organic peroxide initiators such as di-n-propyl peroxydicarbonate, t-butylperoxyneodecanoate, lauroyl peroxide, benzoyl peroxide, and t-butyl hydroperoxide.

  The polymerization temperature is usually about 20 to 90 ° C, preferably 40 to 70 ° C. The polymerization time is usually about 2 to 15 hours, preferably 3 to 11 hours. The polymerization rate is usually about 10 to 90%, preferably 30 to 80% with respect to the vinyl ester charged. The resin content in the solution after polymerization is about 5 to 85% by mass, preferably 20 to 70% by mass.

  After polymerization for a predetermined time or after reaching a predetermined polymerization rate, a polymerization inhibitor is added to the resulting copolymer solution as necessary, and unreacted ethylene gas is removed by evaporation. Remove. As a method for removing unreacted vinyl ester, for example, a copolymer solution is continuously supplied from the upper part of the tower filled with Raschig rings at a constant rate, and an organic solvent vapor such as methanol is blown from the lower part of the tower, A method of distilling a mixed vapor of an organic solvent such as methanol and unreacted vinyl ester from the top and taking out a copolymer solution from which unreacted vinyl ester has been removed from the bottom of the column is employed.

  Next, an alkali catalyst is added to the copolymer solution to saponify the copolymer present in the solution. The saponification method can be either a continuous type or a batch type. Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, alkali metal alcoholate, and the like. The saponification conditions are, for example, in the case of a batch system, the concentration of the alkali catalyst in the copolymer solution is about 10 to 50% by mass, the reaction temperature is about 30 to 65 ° C., and the amount of catalyst used is vinyl ester structural unit 1 It is preferable that about 0.02 to 1.0 mole per mole and saponification time is about 1 to 6 hours.

  The (modified) EVOH after the saponification reaction contains an alkali catalyst, by-product salts such as sodium acetate and potassium acetate, and other impurities. Therefore, it is preferable to remove these by neutralization and washing as necessary. . Here, when the (modified) EVOH after the saponification reaction is washed with water containing almost no metal ions such as ion-exchanged water, chloride ions, etc., part of sodium acetate, potassium acetate, etc. may remain. .

  The polyamide resin (PA) is a general term for polymer compounds having an amide bond formed by a reaction between an acid and an amine, and has good mechanical properties and is resistant to tension, compression, bending, and impact. From the viewpoint of improving gas barrier properties, melt moldability, and interlayer adhesion of the inner liner, the PA is preferably 100 g / 10 min at a melt flow rate (JIS K 7210 1999 (230 ° C. 21.18 N)). More preferably, it is 30 g / 10 minutes.

  Specific examples of the polyamide resin include nylon 6, nylon 6-66, nylon MXD6, and aromatic polyamide.

  The polyvinyl alcohol resin (PVA) is a kind of synthetic resin and can be obtained by saponifying polyvinyl acetate obtained by polymerizing a vinyl acetate monomer.

In addition, the barrier layer preferably has an oxygen permeability of 8.0 × 10 ⁻¹² cm ³ / cm ² · sec · cmHg or less at 20 ° C. and 65% RH in accordance with JIS K7126A, and 1.0 × 10 ⁻¹² more preferably ^{cm 3 / cm 2 · sec ·} cmHg or less, and more preferably ^{5.0 × 10 -13 cm 3 / cm} 2 · sec · cmHg or less. When the oxygen permeability at 20 ° C. and 65% RH exceeds 8.0 × 10 ⁻¹² cm ³ / cm ² · sec · cmHg, the barrier layer must be thickened in order to increase the internal pressure retention of the tire. There is a possibility that the weight of the inner liner cannot be sufficiently reduced.

  Furthermore, the barrier layer is preferably crosslinked. If the barrier layer is not cross-linked, the laminate (inner liner) may be significantly deformed and non-uniform in the vulcanization process of the tire, which may deteriorate the gas barrier properties, flex resistance, and fatigue resistance of the laminate. is there. Here, as a crosslinking method, a method of irradiating energy rays is preferable. Examples of the energy rays include ionizing radiation such as ultraviolet rays, electron beams, X-rays, α rays, γ rays, and among these, electron beams are used. Particularly preferred. The electron beam irradiation is preferably performed after the barrier layer is processed into a molded body such as a film or sheet. Here, the dose of the electron beam is preferably in the range of 10 to 500 kGy, and more preferably in the range of 50 to 300 kGy. When the electron beam dose is less than 10 kGy, crosslinking is difficult to proceed. On the other hand, when the dose exceeds 500 kGy, the molded body tends to deteriorate. In addition, the barrier layer may be subjected to a surface treatment by an oxidation method, a concavo-convex method or the like in order to improve adhesiveness with other layers. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, and the like. Can be mentioned. Among these, corona discharge treatment is preferable.

(Elastic layer)
The elastic body layer constituting the inner liner of the present invention is a layer containing a thermoplastic elastomer, and the other constitution is not particularly limited as long as it is a layer containing a thermoplastic elastomer. For example, a layer made of a thermoplastic elastomer or a layer made of a thermoplastic elastomer composition in which the thermoplastic elastomer exists as a matrix can be mentioned. The matrix means a continuous phase.
Although the above-mentioned barrier layer has a high gas barrier property and a great effect of improving the internal pressure retention property of the tire, it has a significantly higher elastic modulus than the rubber in the tire, so it breaks or cracks due to deformation at the time of bending. There is a risk. For this reason, it is possible to achieve both internal pressure retention and crack resistance of the inner liner by alternately laminating the elastic layer and the barrier layer.

The elastic layer constituting the inner liner of the present invention preferably has an air permeability of 5.0 × 10 ⁻⁸ cm ³ / cm ² · sec · cmHg or less at 20 ° C. and 65% RH. This is because if it exceeds 5.0 × 10 ⁻⁸ cm ³ / cm ² · sec · cmHg, a sudden decrease in internal pressure may not be prevented when a crack occurs in the barrier layer. The air permeability is measured according to JIS K7126A.

  The thermoplastic elastomer used for the elastic layer is not particularly limited. For example, polystyrene-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, polydiene-based thermoplastic elastomer, polyvinyl chloride-based thermoplastic elastomer, chlorinated Examples thereof include polyethylene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and fluororesin-based thermoplastic elastomers. Among these, polyurethane-based thermoplastic elastomers are preferable. In addition, these thermoplastic elastomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  The polystyrene-based thermoplastic elastomer has an aromatic vinyl polymer block (hard segment) and a rubber block (soft segment), and the aromatic vinyl polymer portion forms a physical cross-link and becomes a crosslinking point. On the other hand, the rubber block imparts rubber elasticity. The polystyrene-based thermoplastic elastomer can be classified according to the arrangement pattern of soft segments in the molecule. For example, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene -Isobutylene-styrene block copolymer (SIBS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), etc. A block copolymer of crystalline polyethylene and ethylene / butylene-styrene random copolymer obtained by hydrogenating a block copolymer of butadiene-styrene random copolymer, polybutadiene or ethylene-butadiene random copolymer Obtained by hydrogenating a block copolymer of polymer and polystyrene, for example, also include diblock copolymer of crystalline polyethylene and polystyrene. Among these, styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylene from the balance of mechanical strength, heat stability, weather resistance, chemical resistance, gas barrier properties, flexibility, workability, etc. / Butylene-styrene block copolymer (SEBS) and styrene-ethylene / propylene-styrene block copolymer (SEPS) are preferred.

  The polyolefin-based thermoplastic elastomer includes a thermoplastic elastomer having a polyolefin block such as polypropylene or polyethylene as a hard segment and a rubber block such as an ethylene-propylene-diene copolymer as a soft segment. Such thermoplastic elastomer includes a blend type and an implant type. Examples of the polyolefin-based thermoplastic elastomer include maleic anhydride-modified ethylene-butene-1 copolymer, maleic anhydride-modified ethylene-propylene copolymer, halogenated butyl rubber, modified polypropylene, and modified polyethylene. You can also.

  Examples of the polydiene thermoplastic elastomer include 1,2-polybutadiene TPE, trans 1,4-polyisoprene TPE, hydrogenated conjugated diene TPE, and epoxidized natural rubber. The 1,2-polybutadiene-based TPE is a polybutadiene containing 90% or more of 1,2-bonds in the molecule, and is crystalline syndiotactic 1,2-polybutadiene as a hard segment and amorphous as a soft segment. It consists of 1,2-polybutadiene. Trans 1,4-polyisoprene-based TPE is polyisoprene having a trans 1,4 structure of 98% or more in the molecule, and includes crystalline trans 1,4 segments as hard segments and soft segments. It consists of amorphous trans 1,4 segments.

The polyvinyl chloride thermoplastic elastomer (TPVC) is generally roughly classified into the following three types.
Type 1: High molecular weight polyvinyl chloride (PVC) / plasticized polyvinyl chloride (PVC) blend type TPVC
It is a thermoplastic elastomer made of high molecular weight PVC for the hard segment and PVC plasticized with a plasticizer for the soft segment. In addition, by using high molecular weight PVC for the hard segment, the function of a crosslinking point is given to the microcrystal part.
Type 2: Partially cross-linked PVC / plasticized PVC blend type TPVC
It is a thermoplastic elastomer using PVC in which a partially crosslinked or branched structure is introduced into a hard segment and PVC plasticized with a plasticizer in a soft segment.
Type 3: PVC / elastomer alloy TPVC
It is a thermoplastic elastomer that uses PVC for the hard segment and rubber such as partially crosslinked nitrile butadiene rubber (NBR) or TPE such as polyurethane TPE and polyester TPE for the soft segment.

  The chlorinated polyethylene-based thermoplastic elastomer is a soft resin obtained by reacting polyethylene with chlorine gas in an aqueous suspension or a solvent such as carbon tetrachloride, and a crystalline polyethylene block is a soft segment in the hard segment. A chlorinated polyethylene (CPE) block is used for the segment. In the CPE block, both components of polyethylene and chlorinated polyethylene are mixed as a mixture having a multi-block or random structure.

The polyester-based thermoplastic elastomer (TPEE) is a multi-block copolymer using polyester as a hard segment in a molecule and polyether or polyester having a low glass transition temperature (Tg) as a soft segment. TPEE can be divided into the following types according to the difference in molecular structure, and polyester / polyether type TPEE and polyester / polyester type TPEE dominate.
(1) Polyester / polyether type TPEE
Generally, it is a thermoplastic elastomer using aromatic crystalline polyester as a hard segment and polyether as a soft segment.
(2) Polyester / Polyester type TPEE
A thermoplastic elastomer using an aromatic crystalline polyester as a hard segment and an aliphatic polyester as a soft segment.
(3) Liquid crystalline TPEE
It is a thermoplastic elastomer using rigid liquid crystal molecules as hard segments and aliphatic polyester as soft segments.

  The polyamide-based thermoplastic elastomer (TPA) is a multi-block copolymer using polyamide as a hard segment and polyether or polyester having a low Tg as a soft segment. The polyamide component constituting the hard segment is selected from nylon 6, 66, 610, 11, 12 and the like, and nylon 6 and nylon 12 are mainly used. As the constituent material of the soft segment, a long-chain polyol such as polyether diol or polyester diol is used. Representative examples of polyether polyols include diol poly (oxytetramethylene) glycol (PTMG), poly (oxypropylene) glycol, and the like. Representative examples of polyester polyols include poly (ethylene adipate) glycol, poly (butylene- 1,4 adipate) glycol and the like.

  The fluororesin-based thermoplastic elastomer is an ABA type block copolymer made of fluororesin as a hard segment and fluororubber as a soft segment. Tetrafluoroethylene-ethylene copolymer or polyvinylidene fluoride (PVDF) is used for the fluororesin constituting the hard segment, and vinylidene fluoride-hexafluoropropylene-tetrafluoro is used for the fluororubber constituting the soft segment. An ethylene terpolymer or the like is used. More specifically, it includes vinylidene fluoride rubber, tetrafluoroethylene-propylene rubber, tetrafluoroethylene-perfluoromethyl vinyl ether rubber, phosphazene fluororubber, fluoropolyether, fluoronitroso rubber, perfluorotriazine. And the like. In addition, fluororesin TPE is microphase-separated like other TPE, and the hard segment forms the crosslinking point.

  The polyurethane-based thermoplastic elastomer (TPU) includes (1) a polyurethane obtained by a reaction of a short-chain glycol and an isocyanate as a hard segment, and (2) a polyurethane obtained by a reaction of a long-chain glycol and an isocyanate as a soft segment. Is a linear multi-block copolymer. Here, polyurethane is a general term for compounds having a urethane bond (—NHCOO—) obtained by polyaddition reaction (urethanization reaction) of isocyanate (—NCO) and alcohol (—OH). In the innerliner of the present invention, if the elastomer forming the elastic layer is TPU, the stretchability and thermoformability can be improved by laminating the elastic layer. In addition, since the inner liner can improve the interlayer adhesion between the elastic layer and the barrier layer, the inner liner has high durability such as crack resistance, and even when the inner liner is used by being deformed, the gas barrier property and stretchability are improved. Can be maintained.

  The TPU is composed of a polymer polyol, an organic polyisocyanate, a chain extender and the like. The polymer polyol is a substance having a plurality of hydroxy groups, and is obtained by polycondensation, addition polymerization (for example, ring-opening polymerization), polyaddition or the like. Examples of the polymer polyol include polyester polyol, polyether polyol, polycarbonate polyol, or a cocondensate thereof (for example, polyester-ether-polyol). Among these, polyester polyol or polycarbonate polyol is preferable, and polyester polyol is particularly preferable. In addition, these polymer polyols may be used individually by 1 type, and may be used in combination of 2 or more type.

  Here, for example, according to a conventional method, the polyester polyol may be obtained by condensing a compound capable of forming an ester such as a dicarboxylic acid, an ester thereof, or an anhydride thereof and a low molecular polyol by a direct esterification reaction or an ester exchange reaction. Alternatively, it can be produced by ring-opening polymerization of a lactone.

  It does not specifically limit as dicarboxylic acid which can be used for the production | generation of the said polyester polyol, The dicarboxylic acid generally used in manufacture of polyester is mentioned. Specific examples of the dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, methylsuccinic acid, 2-methylglutaric acid, trimethyladipic acid, 2- C4-C12 aliphatic dicarboxylic acids such as methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid Examples thereof include aromatic dicarboxylic acids such as acid, orthophthalic acid, and naphthalenedicarboxylic acid. These dicarboxylic acids may be used individually by 1 type, and 2 or more types may be mixed and used for them. Among these, an aliphatic dicarboxylic acid having 6 to 12 carbon atoms is preferable, and adipic acid, azelaic acid or sebacic acid is particularly preferable. These dicarboxylic acids have a carbonyl group that is more likely to react with a hydroxy group, and can greatly improve interlayer adhesion with the barrier layer.

  It does not specifically limit as a low molecular polyol which can be used for the production | generation of the said polyester polyol, The low molecular polyol generally used in manufacture of polyester is mentioned. Specific examples of the low molecular polyol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,3-butylene glycol, 1, 4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,8-octane Diol, 2,7-dimethyl-1,8-octanediol, 1,9-nonanediol, 2-methyl-1,9-nonanediol, 1,10-decanediol, 2,2-diethyl-1,3- C2-C15 aliphatic diol such as propanediol; 1,4-cyclohexanediol, cyclo Cyclohexanedicarboxylic methanol, cyclooctane dimethanol, an alicyclic diol such as dimethyl cyclooctane dimethanol; 1,4-bis (beta-hydroxyethoxy) aromatic dihydric alcohols such as benzene. These low molecular polyols may be used alone or in a combination of two or more. Among these, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 2,7-dimethyl-1,8-octanediol, 1,9-nonanediol, 2,8- C5-C12 aliphatic diols having a methyl group in the side chain such as dimethyl-1,9-nonanediol are preferred. The polyester polyol obtained using such an aliphatic diol is likely to react with a hydroxy group, and can greatly improve the interlayer adhesion with the barrier layer. Furthermore, a small amount of a trifunctional or higher functional low molecular polyol can be used in combination with the low molecular polyol. Examples of the trifunctional or higher functional low molecular polyol include trimethylolpropane, trimethylolethane, glycerin, 1,2,6-hexanetriol, and the like.

  Examples of the lactone that can be used to produce the polyester polyol include ε-caprolactone and β-methyl-δ-valerolactone.

  Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene) glycol, and the like. These polyether polyols may be used individually by 1 type, and 2 or more types may be mixed and used for them. Among these, polytetramethylene glycol is preferable.

  Examples of the polycarbonate polyol include fats having 2 to 12 carbon atoms such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 1,10-decanediol. Preferable examples include compounds obtained by polycondensation of a group diol or a mixture thereof by the action of diphenyl carbonate or phosgene.

  The polymer polyol preferably has a lower limit of number average molecular weight of 500, more preferably 600, and even more preferably 700. On the other hand, the upper limit of the number average molecular weight of the polymer polyol is preferably 8,000, more preferably 5,000, and still more preferably 3,000. If the number average molecular weight of the polymer polyol is smaller than the lower limit, the compatibility with the organic polyisocyanate is too high, and the elasticity of the resulting TPU becomes poor. May decrease. On the other hand, if the number average molecular weight of the polymer polyol exceeds the above upper limit, the compatibility with the organic polyisocyanate is lowered, and mixing in the polymerization process becomes difficult. There is a possibility that a stable TPU cannot be obtained. The number average molecular weight of the polymer polyol is a number average molecular weight measured based on JIS-K-1577 and calculated based on the hydroxy group value.

  It does not specifically limit as said organic polyisocyanate, The well-known organic diisocyanate generally used for manufacture of TPU can be used. Examples of the organic diisocyanate include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dichloro-4,4′-diphenylmethane diisocyanate, and toluic acid. Examples include aromatic diisocyanates such as diisocyanates; aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate. Among these, 4,4'-diphenylmethane diisocyanate is preferable from the viewpoint of improving the strength and flex resistance of the obtained inner liner. These organic polyisocyanates may be used alone or in combination of two or more.

  The chain extender is not particularly limited, and a known chain extender generally used in the production of TPU can be used, and the molecular weight is 300 having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule. The following low molecular weight compounds are preferably used. Examples of the chain extender include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol, and the like. . Among these, 1,4-butanediol is particularly preferable from the viewpoint of further improving the stretchability and thermoformability of the obtained inner liner. These chain extenders may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  Examples of the method for producing the TPU include a production method that uses the polymer polyol, the organic polyisocyanate, and a chain extender and that utilizes a known urethanization reaction technique, and uses either a prepolymer method or a one-shot method. May be. In particular, it is preferable to perform melt polymerization in the substantial absence of a solvent, and it is more preferable to perform continuous melt polymerization using a multi-screw extruder.

  In the TPU, the ratio of the mass of the organic polyisocyanate to the total mass of the polymer polyol and the chain extender [isocyanate / (polymer polyol + chain extender)] is preferably 1.02 or less. When the ratio exceeds 1.02, long-term operation stability during molding may be deteriorated.

(Outermost layer)
As shown in FIG. 1, the outermost surface layer constituting the inner liner of the present invention is a layer that is located on the outermost side of the tire among the layers constituting the laminated body 1, and includes the inner surface 5 a of the pneumatic tire and the inner layer. In order to ensure adhesiveness with the liner 1, it is necessary to contain an elastomer component that can be heat-bonded to the diene rubber. Here, the heat bonding refers to bonding the inner surface of the pneumatic tire and the outermost surface layer by heating in a state where the inner liner is attached to the inner surface of the pneumatic tire.
In FIG. 1, the barrier layer is the outermost surface layer 2, but the elastic body layer 3 may be the outermost surface layer 2. In that case also, it is necessary to contain an elastomer component that can be heat-bonded to the diene rubber.

  Here, the elastomer component capable of being thermally bonded to the diene rubber is an elastomer having a certain air barrier property and crack resistance as a member constituting the inner liner and capable of being heat bonded to the diene rubber. If it is a component, it will not specifically limit. From the viewpoint of high barrier properties and crack resistance, the elastomer component is preferably a polymer having a vulcanizable diene moiety, such as natural rubber (NR), butadiene rubber (BR), and isoprene rubber (IR). Styrene butadiene rubber (SBR), modified polymers thereof, and the like.

  Moreover, it is preferable that the elastomer component of the outermost layer has a urethane bond. This is because flexibility can be secured while having excellent adhesion to the tire inner surface.

  Moreover, it is preferable that the elastomer component of the outermost layer has a modifying group capable of bonding with a hydroxy group. This is because when the resin component constituting the barrier layer contains a hydroxy group, high adhesiveness can be realized by hydrogen bonding with the barrier layer. Here, examples of the modifying group that can be bonded to a hydroxy group include an epoxy group, an isocyanate group, and a carboxyl group.

  The content of the elastomer component in the outermost layer is preferably 20% by mass or more. This is because when the content of the elastomer component is less than 20% by mass, the content is too small, and there is a possibility that sufficient adhesion with the inner surface of the pneumatic tire cannot be ensured. Further, from the viewpoint of obtaining better adhesive strength, the content of the elastomer component is more preferably 50% by mass or more.

  Furthermore, the surface of the outermost layer may be subjected to corona treatment.

  The thickness of the outermost layer is preferably in the range of 1 to 1000 μm. If it is less than 1 μm, there is a possibility that sufficient adhesion with the inner surface of the pneumatic tire by the outermost surface layer may not be obtained, on the other hand, if the thickness exceeds 1000 μm, because the outermost surface layer becomes too thick, This is because the tire mass may increase.

  The outermost surface layer and the tire inner surface to be joined are preferably joined by vulcanization. This is because a high adhesive force between the tire inner surface and the outermost surface layer can be secured.

(Laminate)
As shown in FIG. 1, the laminate constituting the inner liner of the present invention is formed by alternately laminating the elastic layer 3 and the barrier layer 4.
By laminating the elastic body layer 3 and the barrier layer 4 alternately, it is possible to suppress defects such as pinholes and cracks generated in the barrier layer from progressing to adjacent layers, and thus the entire laminated body 1 is covered. Cracks and breaks can be prevented, and durability such as high gas barrier properties and crack resistance can be maintained. In addition, the total number of seat layers of the laminate is preferably 7 or more, more preferably 11 or more, and 15 or more so that the effects exhibited by the laminate can be further exhibited. More preferably it is. In addition, the upper limit of the total number of layers of the barrier layer 4 and the elastic body layer 3 is not specifically limited, It can select suitably by the use of the inner liner 1, etc.

  The barrier layer requires that the lower limit of the average thickness of one layer is 0.001 μm, preferably 0.01 μm, and more preferably 0.05 μm. On the other hand, the upper limit of the average thickness of one layer is required to be 10 μm, preferably 7 μm, more preferably 5 μm, further preferably 3 μm, and most preferably 1 μm. When the average thickness of one layer in the barrier layer is less than 0.001 μm, it becomes difficult to form a uniform thickness, and the gas barrier property and crack property of the laminate may be lowered. On the other hand, if the average thickness of one layer exceeds 10 μm, depending on the thickness of the laminate, the number of barrier layers constituting the laminate cannot be sufficiently secured, and the crack resistance may be lowered. There are cases where toughness cannot be imparted. Note that the average thickness of one layer in the barrier layer refers to a value obtained by dividing the total thickness of the barrier layers constituting the laminate by the number of barrier layers.

  For the same reason, the elastic layer requires that the lower limit of the average thickness of one layer is 0.001 μm, preferably 0.005 μm, and more preferably 0.01 μm. For the same reason, the upper limit of the average thickness of one layer in the elastic layer is required to be 40 μm, preferably 30 μm, and more preferably 20 μm. The average thickness of one layer in the elastic layer refers to a value obtained by dividing the total thickness of the elastic layers constituting the laminate by the number of layers of the elastic layers. In addition, the total thickness of the elastic layer is equal to or greater than the total thickness of the barrier layer, that is, the ratio of the total thickness of the elastic layer to the total thickness of the barrier layer (elastic layer / The thickness is preferably such that the (barrier layer) is 1 or more. Thereby, the bending fatigue characteristic until the laminated body reaches the whole layer breakage is improved.

  The thickness of the laminate, which is the sum of the barrier layer and the elastic layer, is preferably in the range of 0.1 to 1000 μm, more preferably in the range of 0.5 to 750 μm, and still more preferably in the range of 1 to 500 μm. If the thickness of the laminate is within the above specified range, it is suitable as an inner liner for a pneumatic tire, and coupled with limiting the average thickness of one layer of the barrier layer and the elastic layer, the gas barrier property, Cracking properties and the like can be further improved.

(Inner liner manufacturing method)
The method for producing the inner liner of the present invention is not particularly limited as long as the barrier layer, the elastic layer and the outermost layer can be laminated and adhered satisfactorily. For example, coextrusion, lamination, coating And publicly known methods such as bonding and adhesion.
Among these, the method for producing the inner liner of the present invention includes a resin composition containing a gas barrier resin, an elastomer composition containing a thermoplastic elastomer, and an elastomer composition containing an elastomer component capable of being heat-bonded to a diene rubber. A method for producing a multilayer structure having a barrier layer and an elastic layer by a multilayer coextrusion method using these compositions is preferable from the viewpoint of high productivity and excellent interlayer adhesion.

  In the multilayer coextrusion method, the resin or resin composition forming the barrier layer, the elastomer or elastomer composition forming the elastic body layer, and the elastomer composition forming the outermost layer are heated and melted to produce different extrusions. The multilayer structure of the present invention is formed by being supplied to an extrusion die from a machine or a pump through each flow path, extruded from the extrusion die in multiple layers, and then laminated and bonded. As this extrusion die, for example, a multi-manifold die, a field block, a static mixer or the like can be used.

(Tire inner surface)
As shown in FIG. 1, the tire inner surface is a surface 5 a that joins the inner liner 1 of the present invention in the pneumatic tire 5.
The rubber component constituting the pneumatic tire 5 preferably includes butyl rubber or halogenated butyl rubber. Here, examples of the halogenated butyl rubber include chlorinated butyl rubber, brominated butyl rubber, and modified rubbers thereof. In addition, as the halogenated butyl rubber, a commercially available product can be used. For example, “Enjay Butyl HT10-66” (registered trademark) [chlorinated butyl rubber manufactured by Enjay Chemical Co., Ltd.], “Bromobutyl 2255” (registered trademark). [Brominated butyl rubber manufactured by JSR Corporation] and “Bromobutyl 2244” (registered trademark) [Brominated butyl rubber manufactured by JSR Corporation]. Examples of the chlorinated or brominated modified rubber include “Exxpro50” (registered trademark) [manufactured by Exxon Corporation].

  The content of butyl rubber and / or halogenated butyl rubber in the rubber component is preferably 50% by mass or more, more preferably 70 to 100% by mass, from the viewpoint of improving air permeability. Here, as the rubber component, diene rubber, epichlorohydrin rubber and the like can be used in addition to butyl rubber and halogenated butyl rubber. These rubber components may be used alone or in combination of two or more.

  Specific examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), cis-1,4-polybutadiene (BR), syndiotactic-1,2-polybutadiene (1,2BR), and styrene. -Butadiene copolymer rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), etc. are mentioned. These diene rubbers may be used alone or in combination of two or more.

  For the pneumatic tire, in addition to the rubber component, compounding agents commonly used in the rubber industry, such as reinforcing fillers, softeners, anti-aging agents, vulcanizing agents, vulcanization accelerators for rubber, scorch An inhibitor, zinc white, stearic acid, and the like can be appropriately blended depending on the purpose. As these compounding agents, commercially available products can be suitably used.

<Pneumatic tire>
The pneumatic tire according to the present invention includes the inner liner described above. Hereinafter, the pneumatic tire of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a partial cross-sectional view of one embodiment of the pneumatic tire of the present invention. The tire shown in FIG. 2 has a pair of bead portions 9 and a pair of sidewall portions 10, and a tread portion 11 connected to both sidewall portions 10, and extends in a toroidal shape between the pair of bead portions 9. Embedded in the bead portion 9 and the carcass 12 that reinforces each of the portions 9, 10, and 11, the belt 13 formed of two belt layers disposed on the outer side in the tire radial direction of the crown portion of the carcass 12, respectively. A bead filler 15 is provided on the outer side in the tire radial direction of the ring-shaped bead core 14, and an inner liner 16 of the present invention is disposed on the inner surface of the tire inside the carcass 12.

  In the illustrated tire, the carcass 12 has a main body portion extending in a toroidal shape between a pair of bead cores 14 embedded in the bead portion 9, and the inside of the tire width direction around each bead core 14 from the inside to the outside. In the pneumatic tire of the present invention, the number of plies and the structure of the carcass 12 are not limited to this.

  In the illustrated tire, the belt 13 includes two belt layers. However, in the pneumatic tire of the present invention, the number of belt layers constituting the belt 13 is not limited thereto. Here, the belt layer is usually composed of a rubberized layer of a cord extending obliquely with respect to the tire equatorial plane. In the two belt layers, the cords constituting the belt layer intersect with each other with the equator plane interposed therebetween. Thus, the belt 13 is formed by laminating. Furthermore, although the tire of the example of illustration is equipped with the bead filler 15, the pneumatic tire of this invention does not need to have the bead filler 15, and can also be equipped with the bead filler of another structure.

  The pneumatic tire of the present invention can be manufactured by a conventional method by applying the above-described inner liner to the inner liner 16. In the pneumatic tire of the present invention, as the gas filled in the tire, normal or air with a changed oxygen partial pressure, or an inert gas such as nitrogen can be used.

(Adhesion method between film and pneumatic unvulcanized tire)
In the method of bonding the inner liner and the unvulcanized tire according to the present invention, the inner liner is disposed on the inner surface of the unvulcanized tire, and the film and the unvulcanized tire are bonded by vulcanization. This is effective in that the inner liner can be attached to the inner surface of the pneumatic tire without separately providing an adhesive layer.
The vulcanization conditions are not particularly limited as long as they are normally used. For example, the vulcanization conditions are 120 ° C. or higher, preferably 125 ° C. to 200 ° C., more preferably 130 to 180 ° C.

  Moreover, in this invention, it is preferable to irradiate an energy ray to the laminated body which comprises the said inner liner, and to bridge | crosslink a film matrix. If the laminate is not cross-linked with an electron beam, the film may be remarkably deformed in the subsequent vulcanization process, so that a uniform layer cannot be maintained, and the resulting laminate may not exhibit a predetermined function. is there.

EXAMPLES Hereinafter, although this invention is demonstrated in more detail using an Example, this invention is not limited to these Examples at all.
Hereinafter, Sample 4 is “Example”, but it should be read as “Comparative Example”.

(Elastic body layer 1)
Thermoplastic polyurethane (TPU) (Kuraray Kuramylon U3190) was used for the elastic layer 1.

(Elastic layer 2)
To a 20 L stainless steel reactor filled with nitrogen, 8000 g of hexane and 2000 g of 1,3-butadiene are added, heated to a temperature of 70 ° C., 21 ml of a hexane solution of diisobutylaluminum hydride (20%) with stirring, ethylaluminum sesquioxide. Add 2.5 ml of hexane solution of chloride (20%) and 2.75 ml of hexane solution of neodymium versatite (8.8%) 60 minutes later, add 10 g of hexamethylene diisocyanate in 200 ml of hexane, add 4 g of ethylene glycol and 0.15 ml of dibutyltin laurate Is dissolved in 200 ml of hexane, and after 60 minutes, 4 g of “Irganox1520” is dissolved in 100 ml of hexane and added. Thereafter, urethane-modified polybutadiene (butadiene-based TPU) obtained by precipitating a polymer in 15 L of isopropanol and drying was used for the elastic body layer 2.

(Elastic body layer 3)
A rubber composition in which 5 parts by mass of a butadiene rubber (BR01 made by JSR) and thermoplastic polyurethane (TPU) [Kuraray Kuraray U3190] is blended with 100 parts by mass of the butadiene rubber is formed in the elastic layer 3 Using.

(Elastic body layer 4)
In a 20 L stainless steel reactor, 2000 g of urethane-modified polybutadiene synthesized in the elastomer layer 2 was dissolved in 8000 g of toluene, and the temperature was adjusted to 50 ° C. Thereafter, 240 ml of formic acid was added with stirring, 1000 g of hydrogen peroxide (30 wt%) was added dropwise little by little, and stirring was continued. Four hours later, Irganox 1520 was dissolved in 100 ml of toluene and added. Thereafter, urethane-modified epoxidized polybutadiene obtained by precipitating the polymer in 15 L of isopropanol and drying was used for the elastic body layer 4.

(Barrier layer 1)
What blended 300 mass parts of the resin composition of the ethylene-vinyl alcohol copolymer used for the below-mentioned barrier layer 2 with respect to 100 mass parts of brominated butyl rubber (JSR Bromobutyl2244) and this brominated butyl rubber rubber, Used as the barrier layer 1.

(Barrier layer 2)
An ethylene-vinyl alcohol copolymer having an ethylene content of 44 mol% and a saponification degree of 99.9% (190 ° C, MFR under 2160 g load: 5.5 g / 10 min) was fined to a particle size of about 2 mm with a pulverizer, and again It was thoroughly washed with a large amount of distilled water. The washed particles are vacuum-dried at room temperature for 8 hours, and then a twin screw extruder (screw: 20 mmφ, full flight, cylinder / die temperature setting: C1 / C2 / C3 / die = 200/200/200/200 (° C.) The resin composition melted at 200 ° C. and pelletized using) was used for the barrier layer 2.
The ethylene content and the degree of saponification of the ethylene-vinyl alcohol copolymer were measured by 1H-NMR measurement using deuterated dimethyl sulfoxide as a solvent [using “JNM-GX-500 type” manufactured by JEOL Ltd.]. It is a value calculated from the obtained spectrum. The ethylene-vinyl alcohol copolymer has a melt flow rate (MFR) of a melt indexer L244 (manufactured by Takara Kogyo Co., Ltd.) filled with a sample in a cylinder with an inner diameter of 9.55 mm and a length of 162 mm, and melted at 190 ° C. After that, using a plunger with a weight of 2160g and a diameter of 9.48mm, apply a load evenly, and the amount of resin extruded per unit time from the 2.1mm diameter orifice provided in the center of the cylinder (g / 10min) I asked for it. However, when the melting point of the ethylene-vinyl alcohol copolymer is around 190 ° C or exceeds 190 ° C, it is measured at a plurality of temperatures above the melting point under a load of 2160g. Is plotted on the vertical axis, and the value calculated by extrapolating to 190 ° C. was taken as the melt flow rate (MFR).

<Samples 1-5>
Then, the laminated body which consists of 3 layers on the following coextrusion molding conditions was produced using the material of each barrier layer, and the material of the elastic body layer using the 2 types 3 layer coextrusion apparatus. The laminate was formed such that the elastic layer / barrier layer / elastic layer was 10 μm / 10 μm / 10 μm.
Extrusion temperature of each resin: C1 / C2 / C3 / die = 170/170/200/200 ° C
・ Extruder specifications for each resin: Thermoplastic polyurethane: 25mmφ extruder P25-18AC [manufactured by Osaka Seiki Co., Ltd.]
Resin composition (C): 20 mmφ extruder lab machine ME type CO-EXT [manufactured by Toyo Seiki Co., Ltd.]
・ T-die specification: 500mm width, 2 types, 3 layers [Plastic Engineering Laboratory Co., Ltd.]
・ Cooling roll temperature: 50 ℃
・ Pick-up speed: 4m / min <Samples 6 and 7>
Laminated body in which elastic layers and barrier layers are alternately laminated in a total of 25 layers (12 barrier layers (each layer has a thickness of 1 μm), 13 elastic layers (each layer has a thickness of 1 μm)) (Microlayer) was formed by coextrusion molding.
Thereafter, using the electron beam irradiation apparatus “Curetron EBC200-100 for production” manufactured by Nissin High Voltage Co., Ltd., the above laminate was irradiated with an electron beam under the conditions of an acceleration voltage of 200 kV and an irradiation energy of 150 kGy to carry out a crosslinking treatment. did.

Thereafter, a rubber composition having the following composition was prepared to produce an unvulcanized rubber-like elastic sheet having a thickness of 2 mm.
(Rubber composition)
Natural rubber: 60 parts by mass Brominated butyl rubber [JSR, Bromobutyl 2244]: 40 parts by mass GPF carbon Black [Asahi Carbon Co., Ltd., # 55] ... 10 parts by mass SUNPAR2280 [Nihon Sun Sekiyu Co., Ltd.] 1 part by mass stearic acid [Asahi Denka Kogyo Co., Ltd.]・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 2 parts by mass vulcanization accelerator [Noxeller DM, manufactured by Ouchi Shinsei Chemical Co., Ltd.] ・ ・ 0.5 parts by mass of zinc oxide [Shiramizu Chemical Co., Ltd.] ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1 part by mass sulfur (manufactured by Karuizawa Refinery) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 3 parts by mass

  Then, the laminated body which irradiated the electron beam was bonded together to the rubber-like elastic body sheet | seat, and the laminated body used as a sample was produced by performing a vulcanization process at 160 degreeC for 15 minute (s).

<Evaluation>
About the laminated body of each sample of an Example and a comparative example, (1) adhesiveness and (2) gas barrier property were evaluated.

(1) Adhesiveness Based on JIS Z0237, the adhesiveness was measured (N / 25 mm) at 90 ° peel and peeling speed of 300 mm / min. The evaluation results are shown in Table 1.
In addition, about the evaluation, the value of sample 1 is set to 100, and other values are indexed. The larger the value, the higher the adhesion and the better the result.
(2) Gas barrier property The sample of the said film was conditioned for 5 days at 20 degreeC and 65% RH. Then, using two sheets of humidity-controlled film, GTR-10X manufactured by GTR Tech Co., Ltd. is used, and the air permeability is measured in accordance with JIS K7126A under the conditions of 20 ° C. and 65% RH. The average of the two films was calculated.
About evaluation, it represented by the index when the average value of sample 1 was set to 100. The higher the index value, the better the gas barrier property and the better the result.

The results in Table 1, laminate sample 3,5～7 embodiment, as compared with the samples 1 and 2 of the laminate of Comparative Example, it was found that none of the barrier and adhesion is high. In particular, the adhesiveness is 1.2 to 6 times higher, indicating that the adhesive strength of the laminate according to the present invention is excellent. As a result, it can be seen that excellent adhesiveness can be obtained while maintaining or improving the gas barrier property by containing an elastomer component capable of heat-adhering to the diene rubber in the elastic layer.

  According to the present invention, it is possible to provide an inner liner and a pneumatic tire that can be joined to the tire inner surface without providing an adhesive layer.

DESCRIPTION OF SYMBOLS 1 Inner liner, laminated body 2 Outermost surface layer 3 Elastic body layer 4 Barrier layer 9 Bead part 10 Side wall part 11 Tread part 12 Carcass 13 Belt 14 Bead core 15 Bead filler 16 Inner liner

Claims (8)

An inner liner for a tire comprising a laminate formed by alternately laminating an elastic body layer containing a thermoplastic elastomer and a barrier layer containing a gas barrier resin,
The outermost layer of at least one of the layers constituting the laminate contains an elastomer component that can be heat bonded to the diene rubber,
The inner liner for a tire, wherein the elastomer component is a polymer having a vulcanizable diene portion and has a urethane bond. The tire inner liner according to claim 1, wherein the elastomer component of the outermost surface layer is at least one of natural rubber, butadiene rubber, isoprene rubber, and styrene butadiene rubber.   The tire inner liner according to claim 1, wherein the gas barrier resin of the barrier layer has a hydroxy group.   4. The tire inner liner according to claim 3, wherein the elastomer component of the outermost surface layer has a modifying group capable of bonding with a hydroxy group of the gas barrier resin. 5.   The tire inner liner according to claim 1, wherein the thermoplastic elastomer is a polyurethane-based thermoplastic elastomer.   A pneumatic tire comprising the tire inner liner according to claim 1. A laminate comprising an elastic body layer containing a thermoplastic elastomer and a barrier layer containing a gas barrier resin are alternately laminated, and at least one outermost layer of the layers constituting the laminate is a diene rubber And an elastomer component that can be heat-bonded, and the elastomer component is a polymer having a vulcanizable diene portion, and a tire inner liner joining method that joins a tire inner liner having a urethane bond. There,
A method for joining tire inner liners, wherein the outermost surface layer and a tire inner surface to be joined are joined by vulcanization. It is a manufacturing method of the inner liner for tires according to claim 1,
A method for producing an inner liner for a tire, wherein the inner liner is produced by coextrusion molding.

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