JP2011245766A - Method for using film-rubber composite in tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for using a film-rubber composite for tires, allowing thin gauge realization, resistance to rubber piecing or staving and effective protection from deterioration in air permeation resistance due to partial thin gauge formation.SOLUTION: A film-rubber composite 6a is allocated in a cavity region of vulcanized tire or in a cavity region of non-vulcanized intermediate tire; provided that the film-rubber composite 6a is obtained by previously press-integrating a film 6a1 and a rubber sheet 6a2 which consists of a rubber composition having a butyl rubber content of ≥97 mass%.

Description

  The present invention relates to a method for using a film-rubber composite in which a film and a rubber sheet made of a rubber composition having a butyl rubber content in a rubber component of 97% by mass or more are used for a tire. The present invention relates to a method of using a film-rubber composite for a tire which is strong against rubber breakage and perforation, and can exhibit excellent inner liner performance capable of effectively preventing a decrease in air permeability resistance due to partial thinning. .

  Conventionally, a rubber composition mainly composed of butyl rubber, halogenated butyl rubber or the like is used for an inner liner disposed as a gas barrier layer on the inner surface of the tire in order to maintain the internal pressure of the tire. In addition, by increasing the content of these butyl rubbers, the air barrier property of the rubber composition is further improved. Therefore, attempts to reduce the thickness of the inner liner and reduce the weight and resources of the tire are actively made. is there. However, such a rubber composition is prone to rubber breakage, and when a rubber composition thinned with a high butyl rubber content is applied to the inner liner, the inner liner is used in a so-called ply joint portion of the carcass ply. There was a problem that cracks (defects such as rubber breaks and holes) were likely to occur.

  In general, since the end portion of the carcass ply forming the carcass has a step in the circumferential joint end, stress is concentrated on the inner liner that contacts the end portion of the circumferential joint due to, for example, expansion during tire molding. As a result, local shrinkage occurs, causing cracking of the inner liner. Furthermore, as a result of investigations by the present inventors, even if such inner liner cracking does not occur, local shrinkage occurs, resulting in a decrease in the thickness of the inner liner at that portion. It was found that the sex decreased.

  In order to solve this problem, as a pneumatic tire that can alleviate stress concentration on the inner liner that contacts the circumferential joint end of the carcass ply and suppress the occurrence of inner liner cracking, at least the circumference of the carcass ply located on the inner liner side can be reduced. A pneumatic tire is disclosed in which a terminal rubber portion is disposed at the end of a directional joint (see Patent Document 1).

  A technique for improving gas barrier properties by improving the inner liner itself has also been proposed. For example, by securing the joint strength of the joint part, while maintaining gas barrier properties and reducing the occurrence of poor air entry, etc., the intermediate layer made of a butyl rubber-based material with excellent air permeation resistance is excellent in adhesiveness. There has been disclosed a pneumatic tire in which an inner liner in which an inner layer and an outer layer made of a natural rubber material are disposed is formed (see Patent Document 2).

  And a rubber composition comprising 50 parts by weight to 70 parts by weight of carbon black and 20 parts by weight to 40 parts by weight of a plasticizer and / or resin with respect to 100 parts by weight of the halogenated butyl rubber. A pneumatic tire covering a joint is disclosed (see Patent Document 3).

JP 2006-224853 A JP 2007-160980 A Japanese Patent Laid-Open No. 7-9807

  However, even with the conventional technology (Patent Documents 1 to 3), the inner liner that has been reduced in weight and reduced in thickness has a risk of running out of rubber and perforating the sheet, and air permeation resistance due to partial reduction in gauge. There is still room for improvement.

  Therefore, an object of the present invention is to provide a tire with a film-rubber composite that can be reduced in thickness, is resistant to rubber breakage and perforation, and can effectively prevent a decrease in air permeability resistance due to partial reduction in gauge. It is to provide a method of use.

  As a result of intensive studies to solve the above problems, the present inventors have used a film-rubber composite in which a film and a rubber sheet made of a rubber composition having a butyl rubber content of 97% by mass or more are used for a tire. The inventors have found that it is possible to reduce the gauge, which is resistant to rubber breaks and perforations, and can effectively prevent a decrease in air permeation resistance due to partial gauge reduction.

  That is, the method of the present invention is characterized in that a film and a rubber composite in which a rubber sheet made of a rubber composition having a butyl rubber content in a rubber component of 97% by mass or more is integrated is used for a tire.

  The film used in the method of the present invention preferably has a Young's modulus at −20 ° C. of 1 MPa to 1500 MPa, and is preferably thermoplastic.

  In the method of the present invention, it is preferable that the film and the rubber composition are integrated by precompression, and the film and the rubber sheet are precompressed with a pressure of 0.01 MPa to 1 MPa. Is more preferable.

  Further, the tire includes a carcass made of one or more carcass plies, and the film-rubber composite is disposed on the inner surface of the tire inside the carcass, and the carcass ply and the film-rubber composite are At least one circumferential joint portion is formed in a posture arranged on the inner surface of the tire, and the circumferential joint portion of the film-rubber composite and the circumferential joint portion of the carcass ply do not overlap each other. Even more preferred.

  By using the film-rubber composite provided by the present invention for a tire, it is possible to make the gauge thinner, resistant to rubber breaks and holes, and effectively preventing a decrease in air permeation resistance due to partial gauge reduction. it can.

It is sectional drawing of the tire radial direction of one embodiment of the tire which used the method of this invention. FIG. 2 is a schematic diagram of the tire equator direction of one embodiment of the tire using the method of the present invention, and shows the structure of the inner liner using the film-rubber composite in the joint portion of the carcass ply according to the partial sectional view of the tire equator direction. Show. It is a partial cross-sectional schematic diagram of the tire equator direction showing the structure of the inner liner in the joint portion of the carcass ply of one aspect of the conventional tire, (a) is an aspect without using the conventional inner liner, (b) One mode using a conventional butyl rubber inner liner is shown.

  The method of the present invention is characterized in that a film and a rubber composite in which a rubber sheet made of a rubber composition having a butyl rubber content in a rubber component of 97% by mass or more is integrated is used for a tire. The film-rubber composite can be used for a tire, and the tire can be produced, repaired, repaired, and the like to impart a high function to the tire.

(Method used for tires)
In the method of the present invention, the use for a tire means that, for example, the film-rubber composite is used for an unvulcanized tire semi-finished product, applied to a tire manufacturing process, or used for a vulcanized tire. Applying to the manufacturing process, and used for semi-finished tires or tires in repairs, repairs, etc. For example, in the tire manufacturing process, the film-rubber composite integrated by pre-bonding may be used so as to be disposed on the inner peripheral surface of a vulcanized tire body part or an unvulcanized tire body part. For example, the film-rubber composite integrated by press-bonding in advance may be used so as to close a repair required part such as a nail hole in a repair or repair process.

(tire)
A tire using the method of the present invention is an object using the film-rubber composite, and may be a tire in a semi-finished product state before vulcanization or a tire of a vulcanized product. Hereinafter, a tire using the method of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view in the tire radial direction of an embodiment of a tire using the method of the present invention, and shows the right half for left-right symmetry. The tire shown in FIG. 1 has a pair of bead portions 1, a pair of sidewall portions 2, and a tread portion 3 connected to both sidewall portions 2, and extends in a toroid shape between the pair of bead portions 1. A carcass 4 that reinforces each of these parts 1, 2, and 3, and a belt 5 composed of two belt layers disposed on the outer side in the tire radial direction of the crown part of the carcass 4; An inner liner 6 using the film-rubber composite is disposed on the inner surface of the tire.
In the illustrated example of the tire, the carcass 4 has a main body portion extending in a toroidal shape between a pair of bead cores 7 embedded in the bead portion 1, and around each bead core 7 from the inner side to the outer side in the tire width direction. In the tire using the method of the present invention, the number of plies and the structure of the carcass 4 are not limited to this.

In the illustrated tire, the belt 5 includes two belt layers. However, in the tire using the method of the present invention, the number of belt layers constituting the belt 5 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 5 is configured by being laminated. Furthermore, the tire of the illustrated example includes a belt reinforcing layer 8 disposed so as to cover the entire belt 5 outside the belt 5 in the tire radial direction. However, the tire using the method of the present invention includes the belt reinforcing layer 8. The belt reinforcing layer having another structure may be provided. Here, the belt reinforcing layer 8 is usually composed of a rubberized layer of cords arranged substantially parallel to the tire circumferential direction.
A tire using the method of the present invention can be produced by a conventional method using the film-rubber composite. In the tire using the method of the present invention, as the gas filled in the tire, normal or oxygen partial pressure changed air, or inert gas such as nitrogen, helium, etc. can be used. Often filled with air.

(Film-Rubber Composite)
The film-rubber composite used in the present invention is obtained by integrating a rubber sheet made of a rubber composition having a butyl rubber content of 97% by mass or more in the rubber component.
A description will be given below with reference to FIG. 2 showing an embodiment of the present invention and FIG. 3 showing a conventional embodiment. Here, FIG. 2 is a schematic diagram in the tire equator direction of one embodiment of the tire using the method of the present invention. It is a schematic diagram showing the structure of the inner liner 6 using the film-rubber composite 6a in the circumferential joint portion 4c of the carcass ply 4a according to a partial sectional view in the tire equator direction.
In the conventional tire shown in FIG. 3, there is a step due to the thickness of the carcass ply 4a at the end of the circumferential joint 4c of the carcass ply 4a. When a conventional butyl rubber inner liner 6b is disposed and an expansion stress or a contraction stress acts during a manufacturing process or a vehicle mounting operation, so-called local contraction (a phenomenon in which the gauge decreases) is observed. When stress cannot be dispersed and stress concentrates in a narrow part, a local contraction occurrence part 6d is observed. When the butyl rubber layer is thin and the butyl rubber content is high, the local shrinkage occurrence portion 6d is easily observed particularly at the step position, and the inner liner crack may occur. Therefore, it has been necessary to take measures to sacrifice the weight of the tire and the air permeation resistance by increasing the thickness of the butyl rubber-based inner liner 6b and reducing the content of butyl rubber.

On the other hand, FIG. 2 shows an embodiment of a tire using the method of the present invention. In the tire provided with the film-rubber composite 6a, the film 6a ₁ and the rubber sheet 6a ₂ are integrated. Excellent mechanical properties and integration properties of the film 6a ₁ (characteristics indicating ease of processing into an integrated product such as adhesion properties to rubber sheets and crimping properties, peeling resistance of the integrated product, deformation followability, Expansion characteristics and contraction stress acting on the integrated rubber sheet 6a ₂ portion can be uniformly dispersed first, and the rubber sheet 6a. The magnitude of the stress borne by ₂ can be dramatically relaxed or reduced (hereinafter referred to as stress dispersibility). Therefore, it is possible to skillfully support drawback thin gauge of undesired due to local contraction of the rubber sheet 6a _2. For this reason, an undesired gauge decrease of the inner liner 6 is suppressed, stress concentration at the circumferential joint portion 4c of the carcass ply 4a is alleviated, and inner cracks can be suppressed. Therefore, it is possible to achieve the desired thin gauge as designed to maximize the air permeation resistance of the inner liner rubber and to extend the service life based on high durability. Can respond to requests.

(the film)
The film used for this invention should just have integration with the said rubber sheet and stress dispersibility, and is not specifically limited. Although the structure of the film is not shown in detail in FIG. 2, it may be a single layer structure film or a multilayer structure film, and a commercially available film can be used. A multilayer structure is preferable for improving the bending resistance. In order to ensure good integration and stress dispersibility, the Young's modulus of the film is preferably 1 MPa to 1500 MPa, and can be adjusted by the structure of the film material and thickness. If it is too soft, it will be torn off together with the butyl rubber, and if it is too hard, the integrity will be impaired and peeling will occur. Further, the film is preferably thermoplastic so that it is suitable for integration, particularly integration by pressure bonding, and the Young's modulus of the film can be adjusted by the structure of the film material and the surface portion.
Although the thickness of a film is based on a raw material and a structure, it is preferable that they are 0.1 micrometer-500 micrometers. This is because handling is difficult when the thickness is less than 0.1 μm, and workability is reduced, and when the thickness exceeds 500 μm, the weight reduction effect is reduced. Further, from the viewpoint of stress dispersibility, it is desirable that the film thickness is uniform throughout the composite.

(Film material)
As a raw material of the film used in the present invention, it is sufficient that the film has integrity and stress dispersibility, and a resin that can improve flexibility and gas barrier properties is preferable. For example, polyamide resins such as nylon 6, nylon 66, nylon 46, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66, nylon 6/66/610, nylon MXD6; polybutylene terephthalate (PBT), Polyester resins such as polyethylene terephthalate (PET), polyetherimide (PEI), polyaryl ester (PAR), polybutylene naphthalate (PBN), polynitrile resins, polymethacrylate resins, ethylene-vinyl acetate copolymers ( EVA), ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), polyvinyl alcohol such as polyvinyl alcohol (PVA), etc., among these, flexibility From the viewpoint of gas barrier properties, the ethylene - vinyl alcohol copolymer (EVOH) is preferred. In addition, these resin may be used individually by 1 type, and may be used in combination of 2 or more type.
The material of the film that can be pressure-bonded to the rubber sheet is preferably a thermoplastic resin and is not particularly limited as long as it has integration by pressure bonding. For example, a polyamide-based resin, a polyester-based resin, a polynitrile-based resin, Examples thereof include thermoplastic resins such as polymethacrylate resins and polyvinyl resins, copolymers having these as main components, and resin compositions containing these resin components as main components.

(Rubber sheet)
The rubber sheet used in the present invention is a main part that develops air permeation resistance, supported by the integrity and stress dispersibility of the film. Details of the rubber composition and the like will be described below.

(Rubber composition)
The rubber composition constituting the rubber sheet used in the present invention is characterized in that the butyl rubber content in the rubber component is 97% by mass or more. Hereinafter, details of each component will be described.

(Rubber component)
The rubber component used in the present invention has a butyl rubber content of 97% by mass or more. Furthermore, in this invention, it is preferable that the compounding ratio of the butyl rubber in a rubber component is 98 mass% or more, More preferably, it is 100 mass%. That is, the rubber component of the rubber composition is preferably made of butyl rubber as the butyl rubber content increases. By using butyl rubber as the rubber component, it is possible to improve the air permeation resistance of the rubber composition, and it is possible to provide a rubber composition having excellent processing characteristics such as mechanical characteristics and pressure-bonding performance. is there.
The butyl rubber in the rubber component may be either a non-halogenated butyl rubber or a halogenated butyl rubber, or a mixture thereof. Among these, the content of halogenated butyl rubber in butyl rubber is preferably 40% by weight or more, more preferably 50% by weight or more, and even more preferably 70% by weight or more. This is because halogenated butyl rubber has excellent air permeation resistance. Here, examples of the halogenated butyl rubber include chlorinated butyl rubber, brominated butyl rubber, and modified rubber thereof. Examples of the chlorinated butyl rubber include “EnjayButyl HT10-66” (trademark, manufactured by Enjay Chemical Co., Ltd.), and examples of the brominated butyl rubber include “bromobutyl 2255” (trademark, manufactured by Exxon), and the modified rubber includes “Expro50”. (A product made by Exxon, a trademark, a chlorinated or brominated modified copolymer of a copolymer of isomonoolefin and paramethylstyrene).
In the present invention, in addition to the butyl rubber, 3% by mass or less can be blended in the rubber component of the rubber composition. Examples of rubber components that can be blended include natural rubber (NR), isoprene synthetic rubber (IR), polybutadiene (BR), styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber (CR). Can be mentioned. These may be used alone or in combination of two or more.

(filler)
The rubber composition is a ratio of 0 to 100 parts by weight of carbon black, 30 to 180 parts by weight of a layered or plate-like inorganic filler, and 0 to 5 parts by weight of a dispersion improver per 100 parts by weight of the rubber component. And the carbon black and the layered or plate-like inorganic filler (hereinafter referred to as layered inorganic filler or the like) in a proportion of 30 to 200 parts by weight in total.

(Carbon black)
The type of the carbon black is not particularly limited, and any one of those conventionally used as a reinforcing filler for rubber can be appropriately selected and used. For example, FEF, SRF, HAF, ISAF, SAF, GPF etc. are mentioned. Among these, those having a nitrogen adsorption specific area (N ₂ SA) of 26 to 170 m ² / g are preferable. The nitrogen adsorption specific area is measured according to ASTM D3037-88.

(Layered plate-like inorganic filler, etc.)
The layered inorganic filler and the like preferably have an aspect ratio of 5 or more and less than 30, and more preferably 7 to 20. If the aspect ratio is less than 5, the effect of improving the air permeation resistance may not be sufficiently exhibited. If the aspect ratio is 30 or more, the dispersion into the rubber component tends to deteriorate, and the air permeation resistance tends to deteriorate. Here, the aspect ratio is determined as a / b from the average major axis a and the average minor axis b by observing the inorganic filler with an electron microscope, measuring the major axis and minor axis for 50 arbitrary particles.
By blending a layered inorganic filler or the like having such an aspect ratio with the rubber component, the air permeation resistance can be improved with a smaller blending amount than conventional carbon black and normal shape inorganic fillers. It becomes possible. This is because a layer structure is formed in processing steps such as extrusion and rolling, the air permeation path is blocked, and the air permeation resistance is effectively exhibited. Furthermore, since the blending amount of the inorganic filler can be reduced, an increase in hardness at a low temperature can be suppressed and durability at a low temperature can be improved as compared with the conventional carbon black and the normal shape inorganic filler.
The layered inorganic filler or the like may be either a natural product or a synthetic product, and is not particularly limited. Specifically, for example, a water-containing composite of kaolin, clay, mica, feldspar, silica and alumina, and kaolin clay is preferred.

(Dispersion improver)
The dispersion improver is used for improving the dispersion of carbon black, layered inorganic filler and the like in the rubber component, and improving the bending fatigue resistance and the like. Examples of the dispersion improver include silane coupling agents and dimethyl stearylamine. These may be used individually by 1 type, and may be used in combination of 2 or more types.

(Other ingredients)
In addition to the above-mentioned rubber components, carbon black, layered inorganic fillers, etc., dispersion improvers, the rubber composition contains compounding agents commonly used in the rubber industry, such as softeners, anti-aging agents, and vulcanization accelerators. An agent, a vulcanization acceleration aid, a vulcanizing agent, and the like can be appropriately selected and blended within a range that does not impair the object of the present invention. As these compounding agents, commercially available products can be suitably used. The rubber composition can be produced by blending rubber components with various compounding agents appropriately selected as necessary, kneading, heating, extruding, and the like.

(Film-Rubber Composite Integration Method)
In the method of the present invention, the method for integrating the film and the rubber sheet is not particularly limited as long as both the integration and stress dispersibility can be exhibited. Specifically, an integration method at the same time as molding by a co-extrusion method or an extrusion laminating method, an integration method in secondary processing by adhesion, adhesion, adhesion, pressure bonding, cross-linking or vulcanization bonding can be mentioned. In the method of the present invention, an integration method by pressure bonding is preferable. This is because the integration of the film and the rubber sheet can be simplified without entering air. The time of integration may be the same as that used for the tire as the inner liner, or may be integrated in advance. In particular, it is preferable to integrate by press-bonding in advance. This is for avoiding an increase in the number of work steps by performing pressure bonding in advance.

(Integration method by crimping)
In the method of the present invention, the integration method by pressure bonding means that a bonding surface of a molded product (the film-rubber composite, etc.) is locally melted by heating, and a molten resin is bonded by applying a light load. It is an integrated method for obtaining a strong bond as an agent. There are electric heating, combustion gas method, hot plate welding method, heat sealing method, hot air welding method, high frequency method, ultrasonic method, frictional heat method and so on. For example, the hot plate welding method is a method in which a heating element such as a metal plate is heated, brought into direct contact with the part to be joined of the film, the surface is softened and melted, pressed in that state, and bonded and integrated by heat conduction. is there. In the method of the present invention, the pressure bonding method is not particularly limited, but pressure bonding with a roll is preferable. This is because the pressure can be applied efficiently.
In the method of the present invention, the film and the rubber sheet are preferably pressure-bonded in advance at a pressure of 0.01 MPa to 1 MPa. This is to avoid an increase in the number of work steps by integrating in advance.

In the present invention, for example, as shown in FIG. 2, the carcass ply 4 and the film-rubber composite 6a are each provided with at least one circumferential joint portion (4c and 6c) in a posture arranged on the inner surface of the tire. Preferably, the circumferential joint portion 6c of the film-rubber composite and the circumferential joint portion 4c of the carcass ply do not overlap each other. This is because the circumferential joint portions (4c and 6c) have an overlap portion although they are slight, and this causes a disturbance in the weight balance in the tire circumferential direction. However, in the case where the thickness of the gauge until it becomes thinner than 500 μm can be achieved, the influence of the weight balance in the tire circumferential direction becomes slight, so the circumferential joint portions (4c and 6c) are overlapped on the contrary. Can be preferred. This is because the film-rubber composite 6a has a large stretchable space and stress is easily relaxed.
Further, from the viewpoint of suppressing a decrease in tire uniformity, it is preferable to form two or more seams, and further to form 5 to 20 seams when the gauge can be reduced. preferable. When the number of seams formed by the laminate exceeds 20, it may be difficult to produce the inner liner. When a plurality of seams are formed in a posture in which the laminate constituting the tire inner liner is disposed on the inner surface of the tire, the inner liner is formed by, for example, overlapping and joining the end portions of the plurality of laminates. Produced.

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

(Examples 1-14, Comparative Examples 1-5)
Examples include an epoxy-modified ethylene-vinyl alcohol copolymer single-layer structure film (thickness 20 μm), a thermosetting urethane elastomer single-layer structure film (thickness 20 μm), a modified ethylene-vinyl alcohol copolymer / thermoplastic polyurethane. A film-rubber composite comprising the five-layer structure film (thickness 100 μm) and a rubber sheet having the composition shown in Table 1 and having the specifications shown in Tables 2 to 3 (butyl rubber content to joint overlap) is prepared. did. The peel resistance of the film-rubber composite was evaluated. The evaluation method is shown below. The evaluation results are shown in Tables 2-3. In addition, a test tire including the film-rubber composite as an inner liner was manufactured and evaluated for tire performance. The evaluation method is shown below. The evaluation results are shown in Tables 2-3. Comparative examples were also prepared and evaluated according to the examples. The evaluation results are shown in Tables 2-3.

1: “Bromobutyl 2245” by JSR alone or “Bromobutyl 224 by JSR”
5 ”and natural rubber, blended according to the butyl rubber content in Tables 2-3:“ Asahi # 55 (N660) ”GPF manufactured by Asahi Carbon Co., Ltd.
3: “Kaolin clay” manufactured by Takehara Chemical Co., Ltd.
4: “Noxeller DM” by Ouchi Shinsei Chemical Co., Ltd.

(Integrated method)
In Examples 1 to 8 and 11 to 13, the film and the rubber sheet were previously pressed and integrated with a pressing pressure of 0.1 to 0.8 MPa using a pressurizable roll device. In Example 9, it was wound on a drum as a step of the manufacturing process at the time of manufacturing, and was integrated by pressure bonding. In Example 10, the film and the rubber sheet were bonded and integrated with a CSM adhesive.

(Evaluation methods)
(Peeling resistance of composite)
For the peel resistance of the composite, a film-rubber composite was subjected to a T-type peel test in accordance with JIS K6854, the peel resistance was measured, and the degree of integration was evaluated. The measured value was expressed as an index with the peel resistance of Comparative Example 1 as 100.

(Peeling resistance with carcass)
The peel resistance to the carcass is determined by performing a T-type peel test on the integrated body of the carcass and the film-rubber composite, butyl rubber (Comparative Examples 2 to 4) or film (Comparative Example 5) according to JIS K6854. Drag was measured. The measured value was expressed as an index with the peel resistance of Comparative Example 1 as 100.

(Rubber sheet)
The crack of the rubber sheet was evaluated by confirming the appearance with a raw tire and checking the presence or absence of the crack. The evaluation results are indicated by ◯: when there is no crack, ×: when there is a crack.

(Air retention evaluation method)
The air retention property (running tire) was 10,000 km on a tire produced as described above, with a pressure of 6 kPa on a rotating drum corresponding to a speed of 80 km / h at an air pressure of 140 kPa. The air retention was evaluated under the following conditions using a non-running tire and a tire running under the above conditions.
For air retention (non-running tire), the internal pressure was 240 kPa after the test tire was mounted on a 6JJ × 15 rim, the internal pressure after 3 months was measured, and the following formula:
Air retention property = ((240−b) / (240−a)) × 100
[Wherein, a is the internal pressure after 3 months of the test tire, and b is the internal pressure after 3 months of a non-running tire (pneumatic tire using a normal rubber inner liner) described in Comparative Example 1 below] did. The other measured values were indexed with the value of Comparative Example 1 as 100.

(durability)
The durability was evaluated based on the appearance of the traveling tire, the presence / absence of peeling of the inner liner (visual observation), and the presence / absence of defects such as inner cracks (visual observation). The evaluation results are indicated by ◯: When there is no defect, ×: When there is a defect.

  As is apparent from Tables 2 to 3, the tires manufactured using the film-rubber composites of the examples as inner liners have a rubber sheet breakage and air compared to the tires manufactured using the inner liners of comparative examples. It was excellent in holding property (air permeation resistance) and durability, and the occurrence of local shrinkage and air entry was remarkably suppressed. The thickness of the rubber sheet can be designed from the air permeation resistance of butyl rubber because it can suppress undesired thin gauges.

  Further, as is clear from Tables 2 and 3, it was found that the butyl rubber content in the rubber component was preferably 97% by mass or more by comparing Examples 1 to 3 and Comparative Example 1.

DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 3 Tread part 4 Carcass 4a Carcass ply 4b Cord 4c Circumferential joint part of carcass ply 5 Belt 6 Inner liner 6a Inner liner using film-rubber composite 6a ₁ Film 6a ₂ Rubber sheet 6b Conventional Butyl rubber inner liner 6c Inner liner circumferential joint 6d Local shrinkage of conventional butyl rubber inner liner 7 Bead core 8 Belt reinforcement layer

Claims (6)

  A method of using for a tire a film-rubber composite in which a rubber sheet made of a rubber composition having a butyl rubber content of 97% by mass or more in a rubber component is integrated.   The method according to claim 1, wherein the film has a Young's modulus at −20 ° C. of 1 MPa to 1500 MPa.   The method according to claim 1, wherein the film is thermoplastic.   The method according to claim 1, wherein the film and the rubber sheet are integrated by press-bonding in advance.   The method according to claim 4, wherein the film and the rubber sheet are pre-bonded with a pressure of 0.01 MPa to 1 MPa. The tire includes a carcass made of one or more carcass plies;
The film-rubber composite is disposed on the inner surface of the tire inside the carcass,
Each of the carcass ply and the film-rubber composite form at least one circumferential joint portion in a posture arranged on the inner surface of the tire;
The method according to claim 1, wherein the circumferential joint portion of the film-rubber composite and the circumferential joint portion of the carcass ply do not overlap each other.

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