KR20100028058A - Pneumatic article provided with a gas tight layer containing a thermoplastic elastomer and a polybutene oil - Google Patents

Abstract

The invention relates to a pneumatic article (1) including an elastomer layer (10) that is inflation gas-tight, characterised in that said elastomer layer (10) includes at least one copolymeric thermoplastic elastomer with polystyrene and polyisobutene blocks and a polybutene oil. Preferably, the block copolymer is a styrene/isobutylene/styrene (SIBS) elastomer and includes between 5 and 50 mass % of styrene, the molecular number average ranging from 30000 and 500000 g/mol and the Tg being lower than 20°C. The polybutene oil, in particlar polyisobutylene oil, is used at a preferential ratio of between 5 and 100 pce (parts per weight per 100 elastomer). The pneumatic article (1) of the invention preferably consists of an air tube or tyre (1) for an automobile.

Description

PNEUMATIC ARTICLE PROVIDED WITH A GAS TIGHT LAYER CONTAINING A THERMOPLASTIC ELASTOMER AND A POLYBUTENE OIL}

The present invention relates to an "inflatable" article, i.e. an article which, by definition, exhibits a form usable when inflated with air or an equivalent inflating gas.

More particularly, the present invention relates to an airtight layer that ensures the impermeability of such inflatable articles, in particular of impermeable tires.

In conventional pneumatic tires of the "tubeless" type (ie, without the inner tube), the radial inner surface is an airtight layer (or, more generally, to allow the inflation tire to expand and remain under pressure). Layer impermeable to any expanding gas). The above tightness ensures a relatively low pressure loss rate, making it possible for the inflated tire to remain in normal operation for a sufficient time, usually weeks or months. In addition, it serves to protect the carcass reinforcement from the diffusion of air entering the interior space of the tire.

Today, this role of the hermetic inner layer or “inner liner” is fulfilled by a composition based on butyl rubber (isobutylene / isoprene copolymer) which has long been famous for its excellent hermeticity.

However, one well-known drawback of compositions based on butyl rubber or elastomer is that compositions based on butyl rubber or elastomer also have high hysteresis losses over a wide temperature range, and this drawback is the rotation of inflation tires. Worsen rolling resistance.

Reducing the hysteresis loss of this hermetic inner layer, and in particular the fuel consumption of the motor vehicle, is therefore a common objective facing current technology.

However, the inventors have found during the study that an elastomeric layer, rather than a butyl layer, makes it possible to obtain an airtight inner layer that responds to that purpose and provides very good airtightness to the airtight inner layer.

Accordingly, according to a first object, the present invention relates to one or more thermoplastic elastomeric copolymers in which the elastomeric layer impermeable to an inflation gas such as air is polystyrene and polyisobutylene blocks (also referred to hereinafter as "block copolymers" "Or" block elastomer ") and a polybutene oil.

Preferably, the polybutene oil is a polyisobutylene (PIB) oil and the block copolymer is a styrene / isobutylene / styrene (SIBS) copolymer.

Compared to butyl rubber, such block copolymers have a major advantage due to thermoplastics that can be worked in the molten (liquid) state, thus providing the possibility of simplified processing, and the addition of polybutene oil allows for airtightness of the inflatable article. Improve the integration of the elastomer layer in the inflatable article through reducing the modulus of the inflatable article and increasing the tackifying power without making it impossible.

In particular, the invention relates to inflatable articles made of rubber, such as pneumatic tires or inner tubes, in particular inner tubes for pneumatic tires.

More particularly, the present invention relates to passenger car types, SUV (sport general purpose vehicles) types, two-wheeled vehicles (especially motorcycles), aircraft, vans, large vehicles (ie, subways, buses, road transport vehicles (lorry, towing vehicles). ), Trailers), off-road vehicles such as agricultural and civil vehicles, and pneumatic tires intended to be mounted on vehicles of other transportation or handling vehicles.

The invention also relates to a method of sealing an inflatable article against an inflating gas, wherein the hermetic elastomer layer described above is introduced thereto during or during the manufacture of the inflatable article.

The invention also relates to the use of an elastomeric layer as described above as a layer impermeable to an inflation gas in an inflatable article.

The invention and its advantages will be readily understood upon view of the following detailed description and exemplary embodiments, as well as a single drawing of this example schematically depicted in a radial cross section of the pneumatic tire according to the invention.

I. Detailed Description of the Invention

In this application, unless otherwise indicated, all percentages indicated are weight percent.

In addition, any range of values represented by the expression “a and b” refers to a range of values that range from more than a to less than b (ie, limited to exclude a and b), with the expression “a to b” Any range of values shown refers to a range of values that range from a to b (ie, including strict limits a and b).

I-1. Hermetic elastomer layer

The inflatable article according to the invention provides at least one elastomer layer or composition comprising at least one thermoplastic elastomer copolymer with polystyrene and polyisobutylene blocks, formulated with at least one polybutene oil as a plasticizer. It is a main feature.

I-1-A. Thermoplastic Elastomer Copolymer with Polystyrene and Polyisobutylene Blocks

The expression “thermoplastic elastomer copolymer with polystyrene and polyisobutylene blocks” (or “block copolymers” or “block elastomers” below) is used for other blocks (eg, polyethylene and / or polybutylene blocks) and / Or one or more styrene blocks (ie, one or more polystyrene blocks) and one or more polyisobutylene blocks (i.e., which may or may not be associated with other monomer units (e.g., unsaturated units such as diene units). It is to be understood as meaning any thermoplastic copolymer comprising at least one polyisobutylene block).

Preferably, such block copolymers are styrene / isobutylene / styrene (SIBS) triblock copolymers.

The expression “SIBS elastomer or copolymer” according to the definition herein may or may not be interrupted by one or more unsaturated units, in particular one or more diene units, such as isoprene units, optionally halogenated in the central polyisobutylene block. Interpreted to mean any styrene / isobutylene / styrene triblock elastomer.

Block elastomers such as SIBS are included in the thermoplastic elastomer (TPE), more strictly thermoplastic styrene (TPS) elastomer family, in a known manner.

It should be recalled here that TPS elastomers are generally in the form of styrene based block copolymers. It is a structural intermediate between the thermoplastic polymer and the elastomer, and in the case of flexible elastomer blocks such as polybutadiene, polyisoprene, poly (ethylene-butylene) or block elastomers such as, for example, SIBS, by polyisobutylene blocks It consists of linked rigid polystyrene blocks. It is often a triblock elastomer with two hard segments connected by flexible segments. Hard and flexible segments may be linear, star or branched in shape. Typically, each such segment or block contains at least more than 5, generally more than 10, substrate units (eg, styrene units and isoprene units for SIBS).

According to one preferred embodiment of the invention, the weight content of styrene in a block copolymer such as SIBS is between 5% and 50%. Below the minimum shown there is a risk that the thermoplastic of the block elastomer is substantially reduced, and above the suggested maximum the elasticity of the hermetic layer can be adversely affected. For this reason, the styrene content is more preferably between 10% and 40%, in particular between 15% and 35%.

The term "styrene" is to be construed herein to mean any monomer based on unsubstituted or substituted styrene, and among substituted styrenes, for example methylstyrene (e.g., α-methylstyrene, β Mention may be made of -methylstyrene, p-methylstyrene, tert-butylstyrene), chlorostyrene (for example monochlorostyrene, dichlorostyrene).

The glass transition temperature (T _g , measured according to ASTM D3418) of the block elastomer is preferably below -20 ° C, more preferably below -40 ° C. T _g values above the minimum temperature may reduce the performance of the hermetic layer when used at very low temperatures, for which use the T _g of the block elastomer is more preferably even below -50 ° C.

The number average molecular weight (indicated by M _n ) of the block elastomer is preferably between 30000 g / mol and 500000 g / mol, more preferably between 40000 g / mol and 400000 g / mol. Below the minimum values shown, in particular due to dilution with polybutene extender oil, there is a risk of adversely affecting the cohesion between the chains of the block elastomer, and also the increase in the use temperature adversely affects mechanical properties, in particular breaking properties. Madly, there is a risk of reducing "hot" performance. In addition, too high molecular weight M _n can be detrimental to the flexibility of the hermetic layer. Accordingly, the inventors have observed that values in the range of 50000 g / mol to 300000 g / mol are particularly suitable, in particular for use of the composition in pneumatic tires.

The number average molecular weight (M _n ) of the block elastomer is determined by size exclusion chromatography (SEC) in a known manner. The sample is first dissolved in tetrahydrofuran at a concentration of about 1 g / l, and then the solution is filtered on a filter with a porosity of 0.45 μm and then injected. The device used is a WATERS Alliance chromatograph. The eluting solvent is tetrahydrofuran, the flow rate is 0.7 ml / min, the temperature of the system is 35 ° C. and the analysis time is 90 min. A set of four Waters columns in series under the trade name STYRAGEL (HMW7, HMW6E and two HT6E) is used. The injection volume of the polymer sample solution is 100 μl. The detector is a Waters 2410 Differential Refractometer and its associated software for handling chromatographic data is the WATERS MILLENNIUM system. Average molecular weights are calculated for calibration curves obtained using polystyrene standards.

The polydispersity index I _p (NB: I _p is M _w / M _n , M _w is the weight average molecular weight) of the block elastomer is preferably less than 3, more preferably I _p is less than 2.

Block elastomers extended with polybutene oil may by themselves constitute a hermetic elastomer layer or may be blended with other elastomers in the elastomer layer.

If any other elastomer is used in the composition, the block elastomer constitutes the main elastomer by weight, preferably greater than 50% by weight, more preferably 70% by weight, of all the elastomers present in the elastomer composition or layer. Exceeding. These additional elastomers in small amounts by weight may be diene elastomers, such as natural rubber or synthetic polyisoprene, butyl rubber or thermoplastic styrene (TPS) elastomers, for example, but not block elastomers such as SIBS, and are compatible with microstructures. Within the limits

TPS elastomers other than block elastomers such as SIBS that may be used in addition to the latter, in particular styrene / butadiene / styrene block copolymers, styrene / isoprene / styrene block copolymers, styrene / isoprene / butadiene / styrene block copolymers, styrene / ethylene Mention may be made of TPS elastomers selected from the group consisting of -butylene / styrene block copolymers, styrene / ethylene-propylene / styrene block copolymers, styrene / ethylene-ethylene-propylene / styrene block copolymers and mixtures of these copolymers. have. More preferably, said optional additional TPS elastomer is selected from the group consisting of styrene / ethylene-butylene / styrene block copolymers, styrene / ethylene-propylene / styrene block copolymers and mixtures of these copolymers.

However, according to one preferred embodiment, the block elastomer, such as SIBS, is the sole elastomer and the sole thermoplastic elastomer is present in the hermetic elastomer layer or composition.

Block elastomers such as SIBS can be processed by extrusion or molding, for example, starting from raw materials available in the form of beads or granules, in a manner customary for TPE.

SIBS elastomers are commercially available, for example, and are commercially available, for example, under the trade name "SIBSTAR" (eg "Sievestar 102T", "Sievestar 103T" or "Sieve" by KANEKA). Star 073T "). These and also their synthesis are described, for example, in European Patent No. 731 112, US Pat. No. 4,946, 899 and US Pat. No. 5,260 383. They were initially developed for biomedical applications, followed by a variety of applications specific to TPE elastomers, such as various components for medical equipment, automotive parts or electrical appliances, sheaths for wires, sealing or elastic parts. (See, eg, European Patent No. 1 431 343, European Patent No. 1 561 783, European Patent No. 1 566 405 and International Patent WO 2005/103146).

However, to the knowledge of the applicants, the use of elastomeric compositions comprising polybutene oils such as PIB and block elastomers such as SIBS, in particular in inflatable articles such as inflation tires, has not been described or suggested in the prior art. In addition, these compositions proved very unexpectedly comparable to conventional compositions based on butyl rubber.

I-1-B. Extender oil

Block elastomers, such as the SIBS described above, also include extender oils (or plasticizing oils) as plasticizers that serve to facilitate processing, particularly incorporation into inflatable articles, through a decrease in the modulus of the hermetic layer and an increase in adhesion. To be used in the composition.

According to the invention, polybutene oils, preferably polyisobutylene oils, are used that offer the best compromise between properties compared to other oils tested, in particular paraffin type conventional oils. At ambient temperature (23 ° C.), in contrast to intrinsically solid resins, in particular tackifying resins, such oils that are relatively viscous may be liquid (ie implicitly and consequently in the form of their containers). Substance).

Examples of polyisobutylene oils are in particular those sold under the trade name “Dynapak Poly” (eg “Dynapak Poly 190”) by Univar, and trade name by BASF. And those sold under "Glissopal" (eg "Glysopal 1000") or "Opanol" (eg "Opanol B12").

The number average molecular weight (M _n ) of the polybutene oil is preferably between 200 g / mol and 25000 g / mol, more preferably even between 300 g / mol and 10000 g / mol. If the M _n value is too low, there is a risk of oil moving out of the composition, and very high M _n values can make the composition too stiff. M _n values between 350 g / mol and 4000 g / mol, in particular between 400 g / mol and 3000 g / mol have proven to be a good compromise for the intended application, in particular for use in pneumatic tires.

The number average molecular weight (M _n ) of the polybutene oil is determined by first dissolving the sample in tetrahydrofuran at a concentration of about 1 g / l, then filtering the solution through a filter with a porosity of 0.45 μm, then injecting it into SEC. Is measured. The device is a Waters Alliance Chromatograph. The eluting solvent is tetrahydrofuran, the flow rate is 1 ml / min, the temperature of the system is 35 ° C. and the analysis time is 30 min. A set of two Waters columns under the trade name "Styragel HT6E" is used. The injection volume of the polymer sample solution is 100 μl. The detector is a Waters 2410 Differential Refractometer, and its associated software for handling chromatographic data is the Waters Millennium System. Average molecular weights are calculated for calibration curves obtained using polystyrene standards.

Those skilled in the art will know how to adjust the amount of polybutene oil in accordance with the particular conditions of use of the hermetic elastomer layer, in particular the inflatable article intended to use it, in view of the following description and embodiments.

Preferably, the polybutene oil content is greater than 5 phr (parts by weight per 100 parts by weight of the total elastomer (ie, any other possible elastomer present in the block elastomer + elastomer layer such as SIBS)), preferably between 5 phr and 100 phr. Do.

Below the minimum value indicated, there is a risk that the elastomeric layer or composition will have too high rigidity for a particular application, whereas above the suggested maximum value, the cohesion of the composition will be insufficient and the impermeability that may be impaired with that application will be lost. There is a danger.

For this reason, in particular for the use of hermetic layers in pneumatic tires, the polybutene oil content is preferably above 10 phr, in particular between 10 and 90 phr, more preferably even above 20 phr, in particular 20 phr and 80 phr is between.

I-1-C. Various additives

The hermetic layer or composition described above may also include various additives conventionally present in the hermetic layer known to those skilled in the art. For example, reinforcing fillers such as carbon black or silica, unreinforced or inert fillers, colorants that can be advantageously used to color compositions, platy fillers that further improve impermeability (e.g., phyllosilicates such as kaolin, Talc, mica, graphite, clay or modified clays (“organoclays”), plasticizers other than extender oils described above, stabilizers such as antioxidants or anti-ozone agents, UV stabilizers, various processing aids or other stable Mention may be made of agents, or accelerators capable of promoting adhesion to the remaining structure of the inflatable article.

In addition to the elastomers described above (block elastomers such as SIBS and other possible elastomers), the hermetic composition will also always comprise a polymer which is compatible with non-elastomeric polymers, for example block elastomers, at a lower weight fraction compared to block elastomers. Can be.

The hermetic layer or composition described above is a compound (at 23 ° C.) that is solid and elastic and especially characterized by its very high flexibility and very high deformationability thanks to its particular formulation.

According to one preferred embodiment of the invention, this hermetic layer or composition has a secant extension modulus (denoted as M10) at 10% elongation of less than 2 MPa, more preferably less than 1.5 MPa (particularly 1 MPa) Less than). This amount is measured at a first elongation (ie no adjustment cycle) at a temperature of 23 ° C. using a pull rate of 500 mm / min (ASTM D412 standard) and normalized to the first cross section of the test sample. do.

I-2. Use of Airtight Layers in Pneumatic Tires

The compositions based on the block elastomers described above can be used as hermetic layers in any type of inflatable article. Examples of such inflatable items may refer to inflatable boats, balloons or balls used for games or sports.

The composition is a hermetic layer (or any layer) in an inflatable article, whether it is a finished product or a semi-finished product made of rubber, most particularly pneumatic tires for automobiles such as motorcycles, passenger cars or industrial vehicles. It is particularly suitable for use as other expanding gases, for example layers impermeable to nitrogen.

This hermetic layer is preferably disposed on the inner wall of the inflatable article or can also be fully integrated into its inner structure.

The thickness of the hermetic layer is preferably greater than 0.05 mm, more preferably between 0.1 mm and 10 mm (particularly between 0.1 mm and 1.0 mm).

Depending on the particular application and the dimensions and pressures involved, it will be readily understood that the method of carrying out the invention may vary and that the hermetic layer has several desirable thickness ranges.

Thus, for example, for passenger car tires, the thickness of the hermetic layer may be at least 0.4 mm, preferably between 0.8 mm and 2 mm. According to another example, for heavy vehicle or agricultural vehicle tires, the preferred thickness may be between 1 mm and 3 mm. According to another example, for pneumatic tires for vehicles or aircraft in civil engineering, the preferred thickness can be between 2 mm and 10 mm.

As shown in the exemplary embodiments below, in comparison to conventional hermetic layers based on butyl rubber, the hermetic compositions described above have the advantage of providing very low hysteresis losses and thus reduced rolling resistance to the inflation tires. Have

II. Exemplary Embodiments of the Invention

The hermetic elastomer layer described above can be advantageously used in pneumatic tires of all types of vehicles, especially industrial vehicles such as passenger cars or heavy vehicles.

By way of example, the accompanying single drawing very schematically shows the radial cross section of the pneumatic tire according to the invention (not to scale).

The pneumatic tire 1 comprises a crown 2 reinforced with a crown stiffener or belt 6, two side walls 3 and two beads 4, each of the beads 4 bead wires It is reinforced with (5). Crown 2 is mounted on a tread (not shown here). The skeleton reinforcement 7 is wound with two bead wires 5 of each bead 4, the upturn 8 of this reinforcement 7 being for example the outside of the pneumatic tire 1. Facing side, where it is shown mounted on a rim 9. The framework reinforcement 7 consists of at least one layer of reinforcement with a cord, for example textile or metal cord, referred to as "radial" cord, as is known per se. In other words, this cord has a circumferential intermediate plane (a plane perpendicular to the axis of rotation of the pneumatic tire located in the intermediate gap of the two beads 4 and passing through the middle of the crown stiffener 6) and the angle between 80 ° and 90 °. They are arranged substantially parallel to one another and extend from one bead to the other.

The inner wall of the pneumatic tire 1 comprises an airtight layer 10, for example about 0.9 mm thick, on the side of the internal cavity 11 of the pneumatic tire 1.

This inner layer (or “inner liner”) is at least a rim flange as long as the inflation tire is in the mounting position, covering the entire inner wall of the inflation tire extending from one sidewall to the other. This defines the radially inner face of the pneumatic tire which is intended to protect the skeleton reinforcement from the diffusion of air entering the inner space 11 of the pneumatic tire. This allows the inflation tire to expand and remain under pressure. Its tightness should ensure a relatively low pressure loss rate, making it possible for the pneumatic tire to remain in normal operation for a sufficient time, usually weeks or months.

Unlike conventional pneumatic tires using a composition based on butyl rubber, the pneumatic tire according to the invention is, in the example, an airtight layer 10, with approximately 55 phr of PIB oil (“Dinapac Poly 190” —M _n the use of about 1000 g / mol Im) and the elastomer block SIBS (styrene content is about 15% increase in, a T _g from about -65 ℃, M _n of about 90000 g / mol is "star sieve 102T") do.

The pneumatic tires provided with the hermetic layer 10 described above can be manufactured before or after vulcanization (or curing).

In the first case (ie, prior to vulcanization of the pneumatic tire), the hermetic layer is simply applied at the desired position in a conventional manner to form layer 10. Vulcanization is then usually carried out. SIBS elastomers are able to withstand the stresses associated with the vulcanization step.

One advantageous manufacturing variant for those skilled in the pneumatic tire industry is to provide a suitable thickness during the first step prior to coating the remaining structure of the pneumatic tire, for example according to manufacturing techniques well known to those skilled in the art. It will consist of placing directly on the building drum (building drum) in the form of a (skim) having a.

In the second case (ie after curing of the inflation tire), the airtight layer is applied to the interior of the cured inflation tire in any suitable manner, for example by bonding, spraying or extrusion and blow molding of a film of suitable thickness. do.

In the examples below, the airtightness is a test sample of a composition based first on butyl rubber on the one hand and on the other hand SIBS ("Sievestar 102T") (with or without PIB extender oil for SIBS elastomers) Was analyzed.

For this analysis, a rigid-wall permeameter is used, placed in an oven (temperature of 60 ° C. in the present invention), equipped with a pressure sensor (calibrated in the range of 0 bar to 6 bar), It was connected to a tube equipped with an expansion valve. The penetrometer could accommodate standard test samples in the form of disks (eg, 65 mm in diameter for the present invention) having a uniform thickness that could range from 3 mm or less (0.5 mm for the present invention). . The pressure sensor was connected to a National Instruments data acquisition card (0 V to 10 V analog 4-channel acquisition) connected to a computer performing continuous acquisition at a frequency of 0.5 Hz (one point every two seconds). . The permeation coefficient (K) is a linear regression line (average 1000) that gives the slope α of the pressure loss through the test sample tested over time after stabilization of the system, ie after obtaining a steady state where the pressure decreases linearly with time. Across the points).

First, the inventors have observed that the permeation coefficient of SIBS used alone, i.e. without containing extender oil or other additives, is very low, and is equal to the permeation coefficient of conventional compositions based on butyl rubber.

At the expense of acceptable loss of impermeability, addition of polybutene oil to SIBS elastomers allows for easy integration and processing of elastomeric compositions or layers into inflatable articles, in particular through reduced modulus and increased adhesion of elastomeric compositions Done

Accordingly, we use, for example, 45 phr and 65 phr extender oils so that the permeation coefficient is greater than 2 (2.2 and 3.4 times, respectively) in the presence of conventional oils such as paraffinic oils. Increased (and thus impermeable), and this coefficient is substantially less than 2, an increase multiple that is substantially not very disadvantageous for use in pneumatic tires in the presence of PIB oil ("Dinapak Poly 190"). It was observed to increase by multiples of (1.5 and 1.6 times, respectively).

For this reason, blends of block elastomers, such as SIBS, and polybutene oils, such as PIB, have been proven to best compromise properties for hermetic layers. We also observed that for these elastomer layers based on SIBS and PIB the modulus M10 is very substantially reduced compared to the control composition (less than 1 MPa compared to 2.3 MPa for the butyl layer).

According to the above laboratory tests, a pneumatic tire (dimensions 195/65 R15) according to the invention of the passenger car type was produced, and its inner wall (without building the rest of the tire, on the building drum) was hermetically sealed with a thickness of 0.9 mm. Covered with layer 10, the tire was then vulcanized. The hermetic layer 10 was formed from SIBS extended with 55 phr of PIB oil as described above.

The pneumatic tires according to the invention were compared to a control tire (Michelin "Energy 3" brand) based on butyl rubber, including conventional hermetic layers of equal thickness. According to the ISO 8767 (1992) method, the rolling resistance of a pneumatic tire was measured on a flywheel.

The inventors have found that the rolling resistance of the pneumatic tires of the present invention is very markedly and unexpectedly reduced by almost 4% compared to the control pneumatic tires to those skilled in the art.

In conclusion, the present invention provides a design of inflation tires that can substantially reduce the hysteresis loss of the hermetic inner layer without unacceptably degrading hermeticity, thereby reducing the fuel consumption of a vehicle equipped with such a tire. To be able.

Claims (14)

An inflatable article with an elastomeric layer, characterized in that it is impermeable to the expanding gas and comprises polybutene oil and at least one thermoplastic elastomer copolymer with polystyrene and polyisobutylene blocks. The inflatable article of claim 1, wherein the block copolymer is styrene / isobutylene / styrene copolymer. The inflatable article according to claim 1, wherein the block copolymer comprises between 5 wt% and 50 wt% styrene. The inflatable article according to claim 1, wherein the T _g of the block copolymer is less than −20 ° C. 5. The inflatable article according to claim 1, wherein the number average molecular weight (M _n ) of the block copolymer is between 30000 g / mol and 500000 g / mol. The inflatable article according to claim 1, wherein the polybutene oil is polyisobutylene oil. The inflatable article according to claim 1, wherein the number average molecular weight (M _n ) of the polybutene oil is between 200 g / mol and 25000 g / mol. 8. The inflatable article according to claim 1, wherein the content of polybutene oil is greater than 5 phr. 9. The inflatable article according to claim 8, wherein the content of polybutene oil is between 5 phr and 100 phr. 10. The inflatable article according to claim 1, wherein the thickness of the hermetic elastomer layer is greater than 0.05 mm, preferably between 0.1 mm and 1.0 mm. The inflatable article according to claim 1, wherein the hermetic layer is disposed on an inner wall of the inflatable article. 12. The inflatable article according to any one of the preceding claims, which is made of rubber. The inflatable article according to claim 1, wherein the article is a pneumatic tire. The inflatable article according to claim 1, wherein the article is an inner tube.

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