FR3067283A1 - MULTILAYER LAMINATE - Google Patents

Abstract

The invention relates to a laminate for a pneumatic object comprising at least three different and superposed layers: an inflation-gas-tight layer consisting of a composition based on at least one diene elastomer and at least one crosslinking system, the elastomer content; diene being in a range from 50 to 100 phr; a bonding layer consisting of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 phr of an oil extension having a number average mass Mn less than or equal to 5000 g / mol; a self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil; the styrene thermoplastic elastomer content being in a range from 50 to 100 phr; and said tie layer being disposed between said inflation gas-tight layer and said self-sealing layer. The invention also relates to the use of this laminate as the inner wall of a tire and relates to a tire comprising at least one laminate as defined above.

Description

The present invention relates to an elastomeric multilayer laminate having sealing properties against inflation gases and anti-puncture properties as well as its use in a pneumatic object such as for example a tire.

In general, a pneumatic object such as a pneumatic tire comprises an internal sealing layer delimiting its internal volume. This layer generally comprises a composition based on butyl rubber known to be impermeable to inflation gases such as air.

When in use, the pneumatic object can be punctured following the penetration of a puncturing object such as a nail or a screw. This perforation causes a leakage of the inflation gases. The loss of pressure following this perforation makes the pneumatic object unusable. In the case of a pneumatic tire, a perforation causes the tire to flatten, the vehicle to stop and the wheel concerned to be replaced by a spare tire.

In order to solve this puncture problem, one of the many existing solutions consists in adding to the inner wall of the pneumatic object an additional layer of a relatively flexible composition which can easily creep. Thus during a perforation, the composition of the additional layer, because of its flexibility and its ability to flow easily, penetrates into the perforation, closes this perforation and avoids the loss of pressure subsequent to this perforation. Such a composition is called self-sealing (or "self-sealing" in English).

The self-sealing compositions are generally associated with the internal sealing layer when making the pneumatic object by using an adhesive layer between these two layers. The assembly of these layers forms an elastomeric laminate. Document WO2009 / 156049A1 describes, for example, an airtight and puncture-proof multilayer elastomeric laminate comprising three layers, a first airtight layer based on butyl rubber, an adhesive layer made of an SIS elastomer (styrene / isobutylene / styrene thermoplastic elastomer) and a self-sealing layer consisting of a SEBS elastomer (styrene / ethylene / butylene / styrene thermoplastic elastomer) and 550 phr of extension oil.

Generally, when the pneumatic object is a pneumatic tire, the laminates are formed before the curing of this pneumatic tire by superimposing the airtight layer, the adhesive layer and the self-sealing layer. Then, the tire is cured. This cooking is necessary so that the adhesion of the layers can take place. In general, this adhesion is achieved by the formation of a crosslinking system between the carbon-carbon double bonds (or unsaturation) of the elastomer of the adhesive layer and of the elastomer of the airtight layer.

However, this method of manufacturing the laminate and the pneumatic tire can prove to be long and does not easily adapt to cooked pneumatic tires, that is to say to the laying of the self-sealing layer after baking said pneumatic tire.

In addition, one of the problems encountered during the process of manufacturing a pneumatic tire is due to the nature of the self-sealing layer which can adhere to the membrane of the cooking press during the cooking phase (also called vulcanization or crosslinking phase) and therefore damage this membrane.

To overcome this problem, a solution envisaged consists in placing a protective film between the self-sealing layer and the tools for assembling the blank of the tire. After vulcanization, it is then necessary to remove this protective film. However, the use of these films poses several problems: they induce at least two additional steps in the process for manufacturing a pneumatic tire: a laying step during the manufacturing of the pneumatic tire before curing and a step of removing a after the tire has been cured. In addition, during the removal of the protective film, fragments of the self-sealing layer may remain on this film causing a discontinuity of the self-sealing layer on the internal wall of the tire.

Thus, there is a need to simplify the process for manufacturing a laminate comprising a gas-tight inflation layer and a self-sealing layer and in particular to have a laminate whose self-sealing layer can adhere to an already baked pneumatic object and therefore on a layer which is gas-tight prior to vulcanization.

In order to improve the laminates comprising a layer which is impermeable to inflation gases and a self-sealing layer and with the aim of simplifying the processes for manufacturing a pneumatic object (in particular a pneumatic tire), the The Applicant has found that a composition based on at least one specific styrenic thermoplastic elastomer, at least one specific thermoplastic elastomer containing a polyisobutylene block and at least one specific extension oil at a high rate promotes the adhesion of 'A self-sealing layer on a layer impermeable to inflation gases which may in particular have been previously crosslinked. This composition serves as a bonding layer and makes it possible to obtain a multilayer laminate which overcomes the aforementioned drawbacks.

Thus, a first object of the present invention relates to a laminate for a pneumatic object comprising at least three different and superposed layers:

a gas-tight inflation layer consisting of a composition based on at least one diene elastomer and at least one crosslinking system, the level of diene elastomer being in a range from 50 to 100 phr ;

- A bonding layer consisting of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 pce of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol;

a self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5,000 g / mol; the level of styrenic thermoplastic elastomer being in a range from 50 to 100 phr; and said tie layer being disposed between said inflation gas tight layer and said self-sealing layer.

The laminate according to the invention provides a satisfactory adhesion between the gas-tight inflation layer and the self-sealing layer. Compared to the solutions of the prior art, the invention is much simpler to implement since it is not necessary to use a protective film; the self-sealing layer by virtue of the bonding layer which can adhere to a coating which is impermeable to inflation gases, in particular when the latter is crosslinked (or baked or vulcanized). By avoiding protective film, it saves materials and simplifies the manufacturing process of a pneumatic object, such as a pneumatic tire. Furthermore, the invention has the additional advantage of not damaging the membranes of the cooking presses.

Another object of the present invention therefore relates to the use of a laminate as defined above as the internal wall of a pneumatic object such as, for example, a pneumatic tire.

The invention also relates to a pneumatic object comprising a laminate as defined above, preferably this object is a pneumatic tire.

Another object of the invention relates to the use of a bonding layer for fixing a self-sealing layer on a layer which is impermeable to inflation gases, use in which:

said bonding layer consists of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 pce of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol, said inflation gas tight layer consists of a composition based on at least one diene elastomer and on at least one crosslinking system, the level of diene elastomer being within a range from 50 to 100 phr; and the self-sealing layer consists of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5,000 g / mol; the content of styrenic thermoplastic elastomer being in a range from 50 to 100 phr.

The invention also relates to a method of fixing a self-sealing layer on the internal wall of a pneumatic object, said self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol; the level of said styrenic thermoplastic elastomer being within a range from 50 to 100 phr, process in which:

(A) there is a pneumatic object, the internal wall of which is made of a gaseous inflation gas layer consisting of a composition based on at least one diene elastomer and at least one crosslinking system, the rate diene elastomer being included in a range from 50 to 100 phr;

(b) applying a bonding layer on said internal wall;

(c) applying said self-sealing layer on said bonding layer, said bonding layer consisting of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol.

1. - DESCRIPTION OF THE FIGURES FIG. 1 schematically represents (without respecting a specific scale) a radial section of a pneumatic tire incorporating a multilayer laminate according to the invention.

2. - METHODS USED

2.1 - Method for measuring the number-average molar mass, the weight-average molar mass and the polydispersity index.

The number-average molar mass (Mn), the weight-average molar mass (Mw) and the polydispersity index (Ip) of the constituents which can be used in the compositions of the layers of the laminate according to the invention (thermoplastic elastomer A styrenic, extension oil, thermoplastic elastomer B with isobutylene block, etc.), are determined in known manner, by steric exclusion chromatography (SEC: Size Exclusion Chromatography) triple detection. This technique has the advantage of measuring average molar masses directly without calibration.

We first determine the increment of refractive index d /// dc of the sample (ie of the constituent of the composition whose Mn and if necessary Mw and Ip are to be determined) . For this, the sample is dissolved beforehand in tetrahydrofuran at different precisely known concentrations (0.5 g / L; 0.7 g / L; 0.8 g / L; 1 g / L and 1.5 g / L ); each solution is then filtered through a filter with a porosity of 0.45 μm. Each solution is then injected directly using a syringe pump into a Wyatt differential refractometer of the commercial name "OPTILAB T-REX" with a wavelength of 658 nm and thermostatically controlled at 35 ° C. For each concentration, the refractive index is measured by the refractometer. Wyatt's ASTRA software draws a line from the detector signal based on the concentration of the sample. The ASTRA software automatically determines the directing coefficient of the line corresponding to the increment of the refractive index of the sample in tetrahydrofuran at 35 ° C (n / a) and at the wavelength of 658 nm.

To determine the average molar masses, use the solution of the sample at 1 g / 1 previously prepared and filtered which is injected into the chromatographic system. The equipment used is a “WATERS alliance” chromatographic chain. The elution solvent is antioxidized tetrahydrofuran, with BHT (2,6-diterbutyl 4-hydroxy toluene) of 250 ppm, the flow rate is 1 ml.min ¹ , the system temperature of 35 ° C and the duration of analysis of 60 min. The columns used are a set of three AGILENT columns with the trade name "PL GEL MIXED B LS". The volume injected with the sample solution is 100 μL. The detection system is composed of a Wyatt differential viscometer with the trade name "VISCOSTARII", a Wyatt differential refractometer with the trade name "OPTILAB T-REX" with a wavelength of 658 nm, and a light scattering detector Wyatt multi angle static with wavelength 658 nm and trade name "DAWN HELEOS 8+".

For the calculation of Mn, Mw and Ip, the value of the refractive index increment d /// dc of the solution of the sample at 1 g / L obtained above is integrated. The chromatographic data processing software is the "ASTRA from Wyatt" system.

2.2 - Method for measuring the thicknesses of the different layers of the laminate The thicknesses of the different layers of the laminate are measured using any conventional method known to those skilled in the art.

For example, we have a sample (2 cm * 2 cm) of the multilayer laminate which is placed on a semi-spherical magnetic observation support of a Leica M205C stereomicroscope. We observe the laminate layer by layer in order to measure the thickness of each layer of the laminate.

2.3 - Method for measuring the glass transition temperature Tg of the polymers The glass transition temperature Tg (hereinafter called Tg) is measured in a known manner by DSC (Differential Scanning Calorimetry) according to standard ASTM D3418 of 1999.

3. - DETAILED DESCRIPTION OF THE INVENTIONF The invention and its advantages will be easily understood in the light of the description, the figure and the exemplary embodiments.

In the present description, unless expressly indicated otherwise, all the percentages (%) indicated are percentages by mass.

On the other hand, any range of values designated by the expression "between a and b" represents the range of values ranging from more than "a" to less than "b" (that is to say bounds a and b excluded) while any range of values designated by the expression "from a to b" means the range of values from "a" to "b" (that is to say including the strict limits a and b).

In the present application, the term "part percent elastomer" or "pce" (usually "phr" in English) the part by weight of a constituent per hundred parts by weight of elastomer s, all the elastomers being combined, thermoplastic or non-thermoplastic, diene or olefinic, etc.

In the context of the invention, the carbon products mentioned in the description may be of fossil or biobased origin. In the latter case, they can be, partially or totally, from biomass or obtained from renewable raw materials from biomass. Are concerned in particular polymers, plasticizers, fillers, etc.

3.1 - Multilayer Laminate A first object of the present invention relates to a laminate for pneumatic object comprising at least three different and superposed layers:

a gas-tight inflation layer consisting of a composition based on at least one diene elastomer and at least one crosslinking system, the level of diene elastomer being in a range from 50 to 100 phr ;

- A bonding layer consisting of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 pce of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol;

a self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol ; the level of styrenic thermoplastic elastomer being in a range from 50 to 100 phr; and said tie layer being disposed between said inflation gas tight layer and said self-sealing layer.

By “composition based on” within the meaning of the present invention, is meant a composition comprising the mixture and / or the reaction product of the various constituents used, some of these basic constituents being capable of, or intended for react with each other, at least in part, during the various phases of manufacturing the composition, in particular during its extrusion or during the mixing phase.

By "different layers" within the meaning of the present invention means layers having non-identical compositions (that is to say whose constituents are different from one composition from one layer to another) or else layers whose compositions are identical but whose thickness of the layers is different.

In the following description, the laminate according to the invention will be called either multilayer laminate or laminate.

The details of the invention will be explained below, by the description first of the gas tight layer of inflation, then of the possible common components to the other two layers of the multilayer laminate. In a second step, the specific elements of each of the other two layers of this laminate are described as well as the individual manufacture of the layers, then finally the process for obtaining the laminate according to the invention.

3.1.1. Inflation gas tight layer As indicated above, the multilayer laminate according to the invention comprises at least one inflation gas tight layer which consists of a composition based on at least one diene elastomer and d 'At least one crosslinking system, the level of diene elastomer being in a range from 50 to 100 phr.

In a preferred embodiment of the invention, the multilayer laminate according to the invention comprises at least one crosslinked layer impermeable to inflation gases.

By "crosslinked layer" within the meaning of the present invention means a layer consisting of a diene elastomeric composition having undergone a crosslinking step, also called baking or vulcanization. At the end of this stage, the carbon-carbon double bonds (also called unsaturations) of the diene elastomer of this layer formed a three-dimensional network between the macromolecular chains of the elastomer. It can be ensured that a layer has been crosslinked by placing the layer in a solvent known to dissolve non-crosslinked elastomers of the same chemical nature. If the layer does not dissolve, the skilled person knows that it is crosslinked.

Those skilled in the art will, in the light of the present description, adjust the formulation of the composition of the airtight layer to inflate gases in order to achieve the desired levels of properties and adapt to the formulation according to the intended application.

• Diene elastomer By elastomer (or "rubber", the two terms being considered as synonyms) of the "diene" type, it is recalled here that a (one or more) elastomer derived from at least one must be understood in known manner in part (that is to say a homopolymer or a copolymer) of diene monomer (s) (ie, carrier (s) of two carbon-carbon double bonds, conjugated or not).

Diene elastomers can be classified into two categories "essentially unsaturated" or "essentially saturated". In general, the term “essentially unsaturated” means a diene elastomer derived at least in part from conjugated diene monomers, having a molar ratio of units or units of diene origin (conjugated dienes) which is greater than 15% (% by moles) ; This is how diene elastomers such as butyl rubbers or copolymers of dienes and of alpha-olefins of the EPDM type do not enter into the preceding definition and can be qualified in particular as “essentially saturated” diene elastomers (molar rate of reasons of weak or very weak diene origin, always less than 15% (% in moles)). In the category of “essentially unsaturated” diene elastomers, the expression “highly unsaturated” diene elastomer is understood in particular to mean a diene elastomer having a molar ratio of units of diene origin (conjugated dienes) which is greater than 50% (% by moles) .

These definitions being given, one means more particularly by diene elastomer capable of being used in the rubber compositions according to the invention:

(a) any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms;

(b) any copolymer obtained by copolymerization of one or more dienes conjugated together or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms;

(c) a ternary copolymer obtained by copolymerization of ethylene, of an α-olefin having 3 to 6 carbon atoms with a non-conjugated diene monomer having of 6 to 12 carbon atoms, such as for example the elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type such as in particular 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene;

(d) a copolymer of isobutene and isoprene (butyl rubber), as well as the halogenated versions, in particular chlorinated or brominated, of this type of copolymer.

Although it applies to any type of elastomer, in particular diene, those skilled in the art will understand that for use as a layer which is impermeable to inflation gases, the present invention is preferably implemented with essentially saturated diene elastomers, in particular with the elastomers of type (d).

In the case of copolymers (b), these can contain from 20% to 99% by weight of diene units and from 1% and 80% by weight of vinyl aromatic units.

By way of conjugated dienes, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di (C1-C5 alkyl) -1, 3-butadienes such as by example 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3butadiene, 2-methyl-3-isopropyl-1 , 3 -butadiene, an aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene.

As vinyl aromatic compounds, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial “vinyl-toluene” mixture, para10 tertiobutyl styrene, methoxystyrenes, chlorostyrenes, vinyl mesitylene, are suitable. divinylbenzene, vinylnaphthalene.

Preferably, the diene elastomer of the composition of the inflation gas tight layer can be chosen from the group consisting of synthetic polybutadienes (abbreviated to “BR”), polyisoprenes (abbreviated to “IR”), natural rubber (abbreviated to “NR”), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

Such copolymers are more preferably chosen from the group consisting of isoprene and isobutene copolymers and mixtures of these copolymers.

Preferably, the diene elastomer of the composition of the inflation gas tight layer is chosen from the group of isoprene and isobutene copolymers, halogenated copolymers of isoprene and isobutene and mixtures of these copolymers. This type of copolymer is also called butyl rubber.

Examples of butyl rubber which are particularly suitable for use in a layer which is impermeable to inflation gases are: isobutylene and isoprene (IIR) copolymers, bromobutyl rubbers such as the bromoisobutyleneisoprene copolymer (BIIR) ) and chlorobutyl rubbers such as the chloroisobutylene isoprene copolymer (CIIR).

The level of diene elastomer in the composition of the gas-tight layer for inflation is in a range from 50 to 100 phr, preferably in a range from 70 to 100 phr.

Preferably, the level of diene elastomer in the composition of the gas-tight layer for inflation is in a range from 70 to 100 phr and the diene elastomer is chosen from the group consisting of copolymers of isoprene and isobutylene, halogenated copolymers of isoprene and isobutylene and mixtures of these copolymers.

• Reinforcing filler The composition of the layer which is impermeable to the inflation gases may also comprise a reinforcing filler. In a known manner, the term "reinforcing filler" means a filler known for its capacity to reinforce a rubber composition which can be used for the manufacture of pneumatic objects, such as pneumatic tires.

One can use in the composition of this layer any reinforcing filler known to those skilled in the art such as an inorganic reinforcing filler or an organic filler such as, for example, carbon black.

Preferably, the reinforcing filler comprises an organic reinforcing filler.

More preferably, the reinforcing filler comprises carbon black.

Carbon black can be used alone or in combination with one or more other reinforcing or non-reinforcing fillers as described below. For example, carbon black can be used with an inorganic reinforcing filler such as silica.

Preferably, the reinforcing filler mainly comprises carbon black.

By “predominantly” or “majority” in connection with a compound, it is meant that this compound is predominant among the compounds of the same type in the composition; that is, it is the one with the highest weight fraction among compounds of the same type. Thus, for example, a so-called majority charge is that representing the largest weight fraction relative to the total weight of all the charges of the composition. Thus, preferably, the reinforcing filler comprises at least 51% by weight of carbon black relative to the total weight of the reinforcing filler, more preferably at least 60% by weight, more preferably still at least 80% by weight.

Preferably, the reinforcing filler consists of carbon black.

As carbon blacks, all carbon blacks are suitable, in particular blacks of the HAF, ISAF, SAF type conventionally used in tires (so-called pneumatic grade blacks). Among the latter, there may be mentioned more particularly the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), such as, for example, the blacks NI 15, N134, N234, N326, N330, N339, N347, N375, or else, depending on the intended applications, the blacks of higher series (for example N660, N683, N772), or even N990.

Preferably, the reinforcing filler comprises an inorganic reinforcing filler.

By "reinforcing inorganic filler" should be understood in the present application, by definition, any inorganic or mineral filler (whatever its color and its origin (natural or synthetic), also called "white" filler, filler “Clear” or even “non-black filler” as opposed to carbon black, capable of reinforcing on its own, without other means than an intermediate coupling agent, a rubber composition intended for manufacturing pneumatic tires, in other words capable of replacing, in its reinforcement function, a conventional carbon black of pneumatic grade; such a load is generally characterized, in a known manner, by the presence of hydroxyl groups (-OH) at its surface.

As reinforcing inorganic fillers, mineral fillers of the siliceous type, in particular silica (S1O2), or of the aluminous type, in particular of alumina (AI2O3), are suitable. The silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET surface as well as a CTAB specific surface, both less than 450 m ² / g, preferably from 30 to 400 m ² / g. In particular, so-called highly dispersible silicas (known as “HDS”) can be used, such as, for example, Ultrasil 7000 from Evonik, Zeosil® 1165 MP and Zeosil® 1115 MP from Solvay, Zeosil® Premium 200MP from Solvay, the Hi-Sil EZ150G silica from PPG, Zeopol 8715, 8745 or 8755 from Huber, silicas as described in applications W003 / 016215 and W003 / 016387. The BET specific surface and the CTAB specific surface are measured according to the method described respectively in standard NF ISO 5794-1, appendix E of June 2010 and appendix G of June 2010.

When the reinforcing filler comprises silica, use is made in known manner of a coupling agent (or bonding agent) at least bifunctional intended to ensure a sufficient connection, of chemical and / or physical nature, between the filler inorganic (surface of its particles) and the diene elastomer. Such coupling agents, in particular silica / elastomer have been described in a very large number of documents, the best known being bifunctional organosilanes carrying alkoxyl function (that is to say, by definition of "alkoxysilanes") and functions capable of reacting with the diene elastomer such as for example polysulfide functions.

• Other fillers Preferably, the composition of the layer which is impermeable to the inflation gases further comprises a non-reinforcing filler (also called an inert filler).

This charge can be in lamellar form.

Preferably, the non-reinforcing filler is chosen from the group consisting of microparticles of natural calcium carbonates (chalk) or synthetic, synthetic or natural silicates (such as kaolin, talc, mica, cloisite), oxides of titanium, aluminas, aluminosilicates (clay, bentonite) and mixtures of these fillers.

Preferably, the non-reinforcing filler is chosen from the group consisting of chalk (natural or synthetic), talc, kaolin and their mixtures.

Preferably, the composition of the gas-tight inflation layer further comprises a semi-reinforcing filler.

Semi-reinforcing fillers are not capable of reinforcing on their own a composition comprising a diene elastomer intended for the manufacture of pneumatic tires, in other words they are not capable of replacing in its reinforcement function, a conventional carbon black of pneumatic grade, however they allow an increase in the tensile modulus of a rubber composition in which they are incorporated, this is why they are called “semi-reinforcing”. As semi-reinforcing filler optionally present in the composition of the layer which is impermeable to the inflation gases, there may be mentioned in particular graphite.

• Crosslinking System [0102] Any type of crosslinking system known to the skilled person can be used.

Preferably, the crosslinking system is a vulcanization system. A vulcanization system is a sulfur-based system (or a sulfur-donating agent) and a primary vulcanization accelerator. To this basic vulcanization system can be added, incorporated during the first non-productive phase and / or during the productive phase as described later, various secondary accelerators or known vulcanization activators such as oxide zinc, stearic acid or equivalent compounds.

• Function of the inflation gas tight layer The inflation gas tight layer makes it possible to inflate and keep a pneumatic object under pressure, in particular a pneumatic tire.

By "pneumatic object" is meant in the sense of the present invention any object which takes its usable form when it is inflated with an inflation gas (or gases) such as air for example.

As examples of such pneumatic objects, mention may be made of inflatable boats, pneumatic tires, balls or balls used for play or sport.

The inflation gas tight layer has sealing properties against inflation gases. These properties make it possible to guarantee a relatively low pressure loss rate and to keep the inflated pneumatic object in normal operating condition for a sufficient duration, normally several weeks or several months.

In a pneumatic tire, this layer has, in addition, in particular the function of protecting the carcass reinforcement from the diffusion of air from the space inside the tire and of preventing the oxidation of the various constituents of this frame.

The sealing properties of the inflation gas tight layer can be evaluated by any usual technique known to those skilled in the art, in particular by a permeability test as described for example in application WO2013 / 060858 in paragraph 1.4 • Thickness of the inflation gas tight layer [0080] Those skilled in the art will, in the light of this description, adjust the thickness of the inflation gas tight layer according to the intended application.

Preferably, the laminate according to the invention comprises at least one layer which is impermeable to inflation gases having a thickness greater than or equal to 0.4 mm.

Preferably, the laminate according to the invention comprises at least one layer which is impermeable to inflation gases having a thickness lying in the range from 0.4 to 2 mm, more preferably between 0.6 to 1.2 mm .

The thickness of the inflation gas tight layer is measured according to the method described above.

• Release agent film on the surface of the inflation gas tight layer [0084] According to a preferred embodiment of the invention, the inflation gas tight layer may have a film of release agents on its surface. release. By "surface of the sealed layer of inflation gas" is meant the surface which is in contact with the inflation gases which are in the cavity of the pneumatic object. By "film" is meant a film of a material (or composition) deposited on the surface of a support. The thickness of a film is less than the thickness of a layer.

The film of release agents and its use are well known to manufacturers of pneumatic objects. Usually, this film is applied to the surface of the non-crosslinked layer which is impermeable to inflation gases according to any technique well known to those skilled in the art. Indeed, the inflation gas tight layer (or internal wall of a pneumatic tire) has a strong raw tack. In order to prevent the raw tire when it sticks to the curing membrane of the vulcanization press and does not damage this press, it is usual to deposit a film of release agents on this internal wall. This film acts as a protective anti-sticky layer.

Preferably, the film of release agents comprising at least one silicone polymer or mixture of silicone polymers and talc. Preferably, the film of release agents consists of a silicone polymer or a mixture of silicone polymers and talc.

The film of release agents can, for example, be obtained by spraying an aqueous suspension of one or more silicone polymers and talc on the surface of the non-crosslinked inflation gas tight layer.

Preferably, the film of release agents has a thickness strictly less than 0.5 mm.

Preferably, the film of release agents has a thickness in a range from 0.02 to 0.3 mm.

The thickness of the film of release agents is measured according to the method described above.

When this release agent film is present on the surface of the gas-tight inflation layer, the layers of the laminate according to the invention are superimposed as follows: the gas-tight inflation layer (optionally crosslinked), a release agent film, the bonding layer and the self-sealing layer.

3.1.2 - Bonding layer and self-sealing layer:

□ Common constituents of these layers As mentioned above, the multilayer laminate according to the invention comprises at least one bonding layer and at least one self-sealing layer, these layers being able in particular to include common constituents.

Elastomers o Styrenic thermoplastic elastomer For the sake of brevity, the following paragraphs will detail the characteristics common to the styrenic thermoplastic A elastomer which can be used in the composition of the bonding layer and that which can be used in the composition of the self- sealing.

Styrenic thermoplastic elastomers (abbreviated to "TPS") are, in known manner, part of the family of thermoplastic elastomers (abbreviated to "TPE"). Intermediate structure between thermoplastic polymers and elastomers, they consist of rigid styrenic thermoplastic blocks linked by flexible elastomer blocks.

The styrenic thermoplastic elastomers which can be used for the implementation of the invention are block copolymers, the chemical nature of the thermoplastic blocks and elastomer blocks can vary.

Structure of the Styrenic Thermoplastic Elastomer The number-average molar mass (denoted Mn) of the styrenic thermoplastic elastomer which can be used in the composition of the bonding layer or in that of the self-sealing layer is preferably less than or equal to 500,000 g / mol. More preferably, it is included in a range ranging from 30,000 to 500,000 g / mol, preferably from 40,000 to 400,000 g / mol, more preferably still from 50,000 g / mol to 300,000 g / mol. Below the minimums indicated, the cohesion between the elastomer chains of these styrenic thermoplastic elastomers, in particular because of its possible dilution (in the presence of an extension oil), is likely to be affected; on the other hand, an increase in the temperature of use risks affecting the mechanical properties, in particular the properties at break, with the consequence of a reduced performance "when hot". Furthermore, an excessively high mass Mn can be penalizing for the implementation. Thus, it has been found that a value within a preferred range of 50,000 to 300,000 g / mol is particularly well suited, in particular for the use of this styrenic thermoplastic elastomer in a composition of a bonding layer and of a self-adhesive layer. - shutter for a laminate.

The number-average molar mass (Mn), the weight-average molar mass (Mw) and the polydispersity index (Ip) of these styrenic thermoplastic elastomers is determined in known manner by steric exclusion chromatography (SEC ) triple detection as described above.

The value of the polydispersity index Ip (reminder: Ip = Mw / Mn with Mw average molar mass by weight and Mn average molar mass by number) of these styrenic thermoplastic elastomers is preferably less than 3; more preferably less than 2 and even more preferably less than 1.5.

In known manner, the TPS have two peaks of glass transition temperature Tg, the lowest temperature being relative to the elastomeric part of the TPS, and the highest temperature being relative to the styrenic thermoplastic part of the TPS. Thus, flexible TPS blocks are defined by a Tg lower than ambient temperature (25 ° C), while rigid blocks have a Tg greater than or equal to 80 ° C.

In the present application, when reference is made to the glass transition temperature of these styrenic thermoplastic elastomers, it is the Tg relative to the elastomer block. These styrenic thermoplastic elastomers preferably have a Tg which is preferably less than 25 ° C, more preferably less than or equal to 10 ° C. A Tg value higher than these minima can reduce the performance of the compositions of the bonding layer or that of the self-sealing layer when used at very low temperature; for such a use, the Tg of these styrenic thermoplastic elastomers is more preferably still less than or equal to -10 ° C. Also preferably, the Tg of these styrenic thermoplastic elastomers is greater than or equal to -100 ° C.

To be both elastomeric and thermoplastic in nature, these styrenic thermoplastic elastomers must be provided with sufficiently incompatible blocks (that is to say different because of their mass, their polarity or their respective Tg) for keep their own properties of elastomeric or thermoplastic block.

TPS can be copolymers with a small number of blocks (less than 5, typically 2 or 3), in which case these blocks preferably have high masses, greater than 15000 g / mol. These TPS can be, for example, diblock copolymers, comprising a styrenic thermoplastic block and an elastomer block. They are also often triblock elastomers with two rigid segments connected by a flexible segment. The rigid and flexible segments can be arranged linearly, in a star or branched. Typically, each of these segments or blocks often contains at least more than 5, generally more than 10 base units (for example styrene units and butadiene units for a styrene / butadiene / styrene block copolymer).

TPS can also include a large number of smaller blocks (more than 30, typically from 50 to 500), in which case these blocks preferably have low masses, for example from 500 to 5000 g / mol, these TPS will be called TPS multiblocks afterwards, and are a chain of elastomeric blocks - styrenic thermoplastic blocks.

In a first variant, these styrenic thermoplastic elastomers are in a linear form. For example, these styrenic thermoplastic elastomers are diblock copolymers: thermoplastic block / elastomer block. These styrenic thermoplastic elastomers can also be triblock copolymers: thermoplastic block / elastomer block / thermoplastic block, that is to say a central elastomer block and two terminal thermoplastic blocks, at each of the two ends of the elastomer block. Also, these multiblock styrenic thermoplastic elastomers can be a linear sequence of elastomeric blocks - thermoplastic blocks.

According to another variant of the invention, these styrenic thermoplastic elastomers useful for the needs of the invention are in a star shape with at least three branches. For example, these styrenic thermoplastic elastomers can then consist of a star-shaped elastomer block with at least three branches and of a styrenic thermoplastic block, situated at the end of each of the branches of the elastomer block. The number of branches of these elastomers can vary, for example from 3 to 12, and preferably from 3 to 6.

According to another variant of the invention, these styrenic thermoplastic elastomers are in branched or dendrimer form. These styrenic thermoplastic elastomers can then consist of a branched elastomer block or dendrimer and a styrenic thermoplastic block, located at the end of the branches of the dendrimer elastomer block.

Nature of the Elastomeric Blocks of Styrenic Thermoplastic Elastomers The elastomeric blocks of the styrenic thermoplastic elastomer of the composition of the bonding layer and that of the composition of the self-sealing layer for the purposes of the invention can be all elastomers known to those skilled in the art. They preferably have a Tg of less than 25 ° C, preferably of less than 10 ° C, more preferably of less than 0 ° C and very preferably of less than -10 ° C. Also preferably, the Tg elastomer block of these styrenic thermoplastic elastomers is greater than -100 ° C.

For elastomer blocks with a carbon chain, if the TPS elastomer block has ethylenic unsaturations (that is to say carbon carbon double bonds), we will then speak of an unsaturated or diene elastomer block (or elastomer unsaturated styrenic thermoplastic). If the TPS elastomer block does not contain ethylenic unsaturation, we will speak of a saturated elastomer block (or saturated styrenic thermoplastic elastomer).

In the case of unsaturated elastomer blocks, this elastomer block of the styrenic thermoplastic elastomer is preferably mainly composed of a diene elastomer part. By predominantly, is meant a rate by weight of diene monomer which is highest relative to the total weight of the elastomer block, and preferably a rate by weight of more than 50%, more preferably of more than 75% and even more preferably of more than 85 %. Alternatively, the unsaturation of the unsaturated elastomer block can come from a monomer comprising a double bond and an unsaturation of cyclic type, this is the case for example in polynorbornene.

Preferably, C4-C14 conjugated dienes can be polymerized or copolymerized to form a diene elastomer block. Preferably, these conjugated dienes are chosen from isoprene, butadiene, piperylene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-1 , 3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl1.3-pentadiene, 4-methyl- 1,3-pentadiene, 2,3-dimethyl- 1,3-pentadiene, 2,5-dimethyl-1,3-pentadiene, 2-methyl-1,4-pentadiene, 1,3-hexadiene, 2-methyl1.3-hexadiene, 2-methyl -1,5-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,319 hexadiene, 5-methyl-1,3-hexadiene, 2,5-dimethyl-1,3 hexadiene, 2,5-dimethyl-2,4hexadiene, 2-neopentyl-1,3-butadiene, 1,3-cyclopentadiene, methylcyclopentadiene, 2-methyl-1,6-heptadiene, 1,3- cyclohexadiene, l-vinyl-1,3cyclohexadiene or a mixture thereof. More preferably, the conjugated diene is isoprene or butadiene or a mixture containing isoprene and / or butadiene.

Alternatively, the diene monomers polymerized to form the elastomer part of the styrenic thermoplastic elastomer can be copolymerized, statistically, with at least one other monomer so as to form an unsaturated elastomer block. According to this variant, the molar fraction of polymerized monomer other than a diene monomer, relative to the total number of units of the elastomer block, must be such that this block retains its elastomer properties. Advantageously, the molar fraction of this other co-monomer can range from 0 to 50%, more preferably from 0 to 45% and even more preferably from 0 to 40%.

By way of illustration, this other monomer capable of copolymerizing with the diene monomer can be chosen from ethylenic monomers such as ethylene, propylene, butylene, vinylaromatic type monomers having from 8 to 20 atoms of carbon as defined below or alternatively, it may be a monomer such as vinyl acetate.

When the co-monomer is of vinylaromatic type, it advantageously represents a molar fraction in units on the total number of units in the thermoplastic block from 0 to 50%, preferably ranging from 0 to 45% and even more preferably ranging from 0 at 40%. By way of vinyl aromatic compounds, the styrenic monomers mentioned below are suitable, namely methylstyrenes, paratertio-butylstyrene, chlorostyrenes, bromostyrenes, fluorostyrenes or even para-hydroxy-styrene. Preferably, the vinylaromatic type co-monomer is styrene.

A saturated elastomer block consists of a polymer block obtained by the polymerization of at least one (that is to say one or more) ethylenic monomer, that is to say comprising a double bond carbon - carbon. Among the blocks originating from these ethylenic monomers, mention may be made of polyalkylene blocks such as random ethylene-propylene or ethylene-butylene copolymers. These saturated elastomeric blocks can also be obtained by hydrogenation of unsaturated elastomeric blocks. It can also be aliphatic blocks from the family of polyethers, polyesters, or polycarbonates.

In the case of saturated elastomeric blocks, this elastomeric block of the styrenic thermoplastic elastomer is preferably composed mainly of ethylenic units. By predominantly, is meant a rate by weight of ethylenic monomer that is higher relative to the total weight of the elastomer block, and preferably a rate by weight of more than 50%, more preferably of more than 75%, more preferably of more than 85% , more preferably more than 90%, and even more preferably still more than 95%.

By way of illustration, the other monomers capable of copolymerizing with the ethylenic monomer can be chosen from diene monomers (as defined below, more particularly, conjugated diene monomers having 4 to 14 carbon atoms such as defined below (for example butadiene), the vinyl aromatic type monomers having from 8 to 20 carbon atoms as defined below or also, it may be a monomer such as vinyl acetate.

When the co-monomer is of vinyl aromatic type, the weight rate of this co-monomer relative to the total weight of the elastomer block is within a range ranging from 0 to 50%, preferably ranging from 0 to 45% and again more preferably ranging from 0 to 40%. As vinyl aromatic compounds, the styrenic monomers mentioned below are suitable in particular, in particular styrene, methylstyrenes, para-tertio-butylstyrene, chloro styrene s, bromostyrenes, fluorostyrenes or also para-hydroxy-styrene. Preferably, the vinylaromatic type co-monomer is styrene.

When the co-monomer is of the diene type, the weight content of this co-monomer relative to the total weight of the elastomer block is within a range ranging from 0 to 15%, preferably ranging from 0 to 10% and again more preferably ranging from 0 to 5%. As diene co-monomer suitable in particular are C4-C14 conjugated dienes. In this case, these are random copolymers. Preferably, these conjugated dienes are chosen from isoprene, butadiene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-l, 3- butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3pentadiene, 2,3-dimethyl-1,3 -pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,3-hexadiene, 5-methyl-1, 3-hexadiene, 2,3-dimethyl-1,3-hexadiene, 2,4-dimethyl-1,3-hexadiene, 2,5-dimethyl-1,3hexadiene, 2-neopentylbutadiene, 1,3 -cyclopentadiene, 1,3-cyclohexadiene, l-vinyl-1,3-cyclohexadiene or a mixture thereof. More preferably, the conjugated diene is isoprene or a mixture containing isoprene.

Preferably, the elastomeric blocks of these styrenic thermoplastic elastomers have in total a number-average molar mass (“Mn”) ranging from 25,000 to 350,000 g / mol, preferably from 35,000 to 250,000 g / mol so as to give these styrenic thermoplastic elastomers good elastomeric properties and sufficient mechanical strength compatible with the use in compositions constituting the bonding layer and the self-sealing layer of the laminate according to the invention.

The elastomer block can also be a block comprising several types of ethylenic, diene or styrenic monomers as defined above.

The elastomer block can also be made up of several elastomer blocks as defined above.

Nature of the styrenic thermoplastic blocks of the styrenic thermoplastic elastomers The proportion of the styrenic thermoplastic blocks relative to the styrenic thermoplastic elastomer, as defined for use in the compositions of the bonding layer and of the self-sealing layer, is determined in particular by the thermoplastic properties that said copolymers must have. The styrenic thermoplastic blocks are preferably present in sufficient proportions to preserve the thermoplastic nature of these elastomers which can be used in the compositions of the bonding layer and of the self-sealing layer of the laminate of the invention. The minimum level of styrenic thermoplastic blocks in these styrenic thermoplastic elastomers can vary depending on the conditions of use of these copolymers. On the other hand, the capacity of these styrenic thermoplastic elastomers to deform during the preparation of the composition of the bonding layer and that of the self-sealing layer can also contribute to determining the proportion of the styrenic thermoplastic blocks.

The styrenic thermoplastic blocks are obtained from styrenic monomers.

By styrenic monomer should be understood in the present description any monomer comprising styrene, unsubstituted as substituted; among the substituted styrenes, mention may be made, for example, of methylstyrenes (for example o-methylstyrene, m-methylstyrene or p-methylstyrene, alpha-methylstyrene, alpha-2-dimethyl styrene, al pha- 4-dimethyl styrene or diphenylethylene), para-tertio-butyl styrene, chlorostyrenes (for example o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6- dichlorostyrene or 2,4,6-trichlorostyrene), bromostyrenes (for example o-bromostyrene, m-bromostyrene, p-bromostyrene, 2,4-dibromostyrene, 2,6-dibromostyrene or 2, 4,6-tribromostyrene), fluorostyrenes (for example o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, 2,4-difluorostyrene, 2,6-difluorostyrene or 2,4,6-trifluorostyrene ) or para-hydroxy-styrene.

Preferably, the weight content of styrenic monomers (preferably styrene monomer) in these styrenic thermoplastic elastomers is between 5% and 50%. Below the minimum indicated, the thermoplastic nature of these elastomers may decrease appreciably while above the recommended maximum, the elasticity of the composition of the bonding layer and that of the self-sealing layer may be affected. For these reasons, the content by weight of styrenic monomers (preferably styrene monomer) in these styrenic thermoplastic elastomers is more preferably between 10% and 40%.

Preferably, the thermoplastic blocks of these styrenic thermoplastic elastomers have in total a number-average molar mass ("Mn") ranging from 5000 g / mol to 150,000 g / mol, so as to give these styrenic thermoplastic elastomers good elastomeric properties and sufficient mechanical strength compatible with the use in compositions for a bonding layer and a self-sealing layer.

The thermoplastic block can also be made up of several thermoplastic blocks as defined above.

Examples of Styrenic Thermoplastic Elastomers [00128] Styrenic thermoplastic elastomers are well known to those skilled in the art and are commercially available from Kraton or from Kaneka, for example.

o Other elastomers The composition of the bonding layer and that of the self-sealing layer may optionally comprise at least one (that is to say one or more) diene elastomer.

By “diene” elastomer or rubber, must be understood in known manner one (one means one or more) elastomer derived at least in part (ie; a homopolymer or a copolymer) of diene monomers (monomers carrying two double bonds carbon carbon, conjugated or not). These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". In general, the expression “essentially unsaturated” means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of units or units of diene origin (conjugated dienes) which is greater than 15% (mol%). In the category of “essentially unsaturated” diene elastomers, the expression “highly unsaturated” diene elastomer is understood in particular to mean a diene elastomer having a rate of units of diene origin (conjugated dienes) which is greater than 50% (mol%). This is how diene elastomers such as certain butyl rubbers or the copolymers of dienes and alpha olefins of the EPDM type can be qualified as “essentially saturated” diene elastomers (rate of units of diene origin low or very low, always less than 15% (% by mole) These definitions being given, the term “diene elastomer” is understood to mean more particularly, whatever the above category, capable of being used in the compositions in accordance with the invention:

(a) - any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms;

(b) - any copolymer obtained by copolymerization of one or more dienes conjugated together or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms;

(c) - a ternary copolymer obtained by copolymerization of ethylene, of an alphaolefin having 3 to 6 carbon atoms with a non-conjugated diene monomer having of 6 to 12 carbon atoms, such as for example the elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type such as in particular 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene;

(d) - a copolymer of isobutene and isoprene (butyl diene rubber), as well as the halogenated, in particular chlorinated or brominated, versions of this type of copolymer.

Preferably, the diene elastomer is chosen from the group consisting of polybutadienes (abbreviated to "BR"), synthetic polyisoprenes (abbreviated to "IR"), natural rubber (abbreviated to "NR"), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

• Extension oil The third essential constituent of the composition of the binding layer is an extension oil (or plasticizer oil), used at a high rate, of at least 140 phr and having a molecular average mass in number less than or equal to 5000 g / mol.

The second essential constituent of the composition of the self-sealing layer is an extension (or plasticizing oil), used at a high rate, of at least 140 phr and having a number average molecular mass less than or equal to 5000 g / mol.

It is possible to use, in the present invention, whatever the type of layer, any extension oil, preferably of weakly polar character, capable of extending, plasticizing styrenic thermoplastic elastomers.

At room temperature (23 ° C), these oils, more or less viscous, are liquids (that is to say, as a reminder, substances having the capacity to eventually take the form of their container) , as opposed in particular to resins, in particular tackifiers, which are by nature solid.

Preferably, the extension oil is chosen from the group consisting of polyolefin oils (that is to say derived from the polymerization of olefins, monoolefins or diolefins), paraffinic oils, naphthenic oils (low or high viscosity), aromatic oils, mineral oils, and mixtures of these oils.

More preferably, the extension oil is chosen from the group consisting of polyolefin oils, paraffin oils and mixtures of these oils.

Even more preferably, the extension oil is a polyolefin oil or a mixture of polyolefin oils. This oil has demonstrated the best compromise in properties compared to the other oils tested, in particular to a conventional oil of the paraffinic type.

Even more preferably, the extension oil is a polyolefin oil chosen from the group consisting of polybutene oils and mixtures of these oils.

Even more preferably, the extension oil is chosen from the group consisting of polyisobutylene oils and mixtures of these oils.

By way of examples, polyisobutylene oils are sold in particular by the company Univar under the name "Dynapak Poly" (eg "Dynapak Poly 190"), by BASF under the names "Glissopal" (eg "Glissopal 1000 ”), By the company INEOS under the names“ H100 ”,“ H300 ”,“ H1200 ”,“ H1500 ”or“ H1900 ”; paraffinic oils are marketed, for example, by ExxonMobil under the names “Primol 352”, “Primol 382” or “Primol 542” or under the names “Flexon815” or “Flexon715”.

• Other additives The composition of the bonding layer and that of the self-sealing layer may also comprise various additives. Typically, these additives are present in small quantities (preferably at rates of less than 10 phr, more preferably less than 5 phr), and are, for example, reinforcing fillers such as carbon black, non-reinforcing or inert fillers such as defined above, protective agents such as anti-UV, antioxidants or anti-ozonants, various other stabilizers, coloring agents advantageously usable for coloring the self-sealing composition.

□ Self-sealing layer As indicated above, the laminate according to the invention comprises at least one self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr. 'an extension oil having a number average mass Mn of less than or equal to 5,000 g / mol; the content of styrenic thermoplastic elastomer being in a range from 50 to 100 phr.

Those skilled in the art will, in the light of the present description, adjust the formulation of the composition of the self-sealing layer in order to achieve the desired levels of properties and adapt to the formulation for the intended application. .

• Constitution of the self-sealing layer In the self-sealing layer of the laminate of the invention, at least one styrenic thermoplastic elastomer as defined above is used, with all the structural preferences, of a chemical nature of the thermoplastic blocks. and elastomeric expressed previously.

According to one embodiment of the composition of the self-sealing layer, the styrenic thermoplastic elastomer is chosen from the group consisting of saturated styrenic thermoplastic elastomers and mixtures of these elastomers.

In this embodiment, preferably, the styrenic thermoplastic elastomer saturated with the composition of the self-sealing layer is chosen from the group consisting of styrene / ethylene / butylene (SEB) copolymers,

styrene / ethylene / propylene (SEP) copolymers, the copolymers styrene / ethy 1 ene / ethy 1 ene / propy 1 ene (PBC), the copolymers styrene / ethy 1 ene / buty lene / styrene (SEBS), the copolymers styrene / ethy 1 ene // propy 1 ene / styrene (SEPS), the copolymers

styrene / ethylene / ethylene / propylene / styrene (SEEPS) and mixtures of these copolymers.

Even more preferably, the styrenic thermoplastic elastomer saturated with the composition of the self-sealing layer is chosen from the group consisting of styrene / ethylene / butylene / styrene copolymers (SEBS), styrene / ethylene / propylene copolymers / styrene (SEPS) and mixtures of these copolymers.

Preferably, the styrenic thermoplastic elastomer saturated with the composition of the self-sealing layer is identical to the styrenic thermoplastic elastomer saturated with the bonding layer, including in its preferred variants.

According to another embodiment of the composition of the self-sealing layer, the styrenic thermoplastic elastomer is chosen from the group consisting of unsaturated styrenic thermoplastic elastomers and mixtures of these elastomers.

In this embodiment, preferably, the unsaturated styrenic thermoplastic elastomer of the composition of the self-sealing layer is chosen from the group consisting of styrene / butadiene copolymers (SB), styrene / isoprene copolymers ( SI), styrene / butadiene / butylene copolymers (SBB), styrene / butadiene / isoprene copolymers (SBI), styrene / butadiene / styrene copolymers (SBS), styrene / butadiene / butylene / styrene copolymers, styrene / isoprene / styrene copolymers (SIS), styrene / butadiene / isoprene / styrene copolymers (SBIS) and mixtures of these copolymers.

Whatever the chemical nature of the styrenic thermoplastic elastomer which can be used, the composition of the self-sealing layer comprises an extension oil having a number average mass Mn of less than or equal to 5000 g / mol as described above. , with all the structural, chemical preferences expressed ...

Preferably, the oil for extending the composition of the self-sealing layer is chosen from the group consisting of polyolefin oils, paraffin oils, naphthenic oils, aromatic oils, mineral oils, and mixtures of these oils.

Preferably, the oil for extending the composition of the self-sealing layer is a polyolefin oil chosen from the group consisting of polybutene oils and mixtures of these oils.

Preferably, the oil for extending the composition of the self-sealing layer is chosen from the group consisting of polyisobutylene oils and mixtures of these oils.

Preferably, the number-average molar mass (Mn) of the oil for extending the composition of the self-sealing layer is within a range ranging from 300 to 5000 g / mol, more preferably still ranging from 350 to 3000 g / mol. For masses Mn of less than 300 g / mol, the latter could migrate outside the self-sealing layer, while masses greater than 5000 g / mol could cause excessive stiffening of the self-sealing layer.

The number-average molar mass (Mn), the weight-average molar mass (Mw) and the polydispersity index (Ip) of the extension oil which can be used in the compositions of the self-sealing layer is determined in a known manner by triple detection size exclusion exclusion chromatography (SEC: Size Exclusion Chromatography) as described above.

Preferably, the extension oil of the composition of the self-sealing layer is identical to or different from the extension oil of the bonding layer, more preferably identical to that of the bonding layer.

Preferably, the rate of oil extension of the self-sealing layer is in a range from 140 to 700 phr, more preferably from 145 to 600 phr. Below the minimum indicated, the self-sealing layer may have a stiffness that is too high for certain applications, while beyond the recommended maximum, there is a risk of insufficient cohesion of the self-sealing layer. For this reason, the degree of extension oil is more preferably between 140 and 700 phr, in particular for the use of the self-sealing layer in a multilayer laminate.

Preferably, the composition of the self-sealing layer may further comprise a polyolefin having a number-average molar mass Mn ranging from 10,000 to 550,000 g / mol. By “polyolefin” is meant within the meaning of the present application an essentially saturated aliphatic polymer obtained by polymerization of at least one (that is to say one or more) olefinic monomer, that is to say having a weight content of units of olefinic origin greater than or equal to 85%. An olefinic monomer has one (and only one) carbon-carbon double bond. Preferably, this polyolefin comprises units derived from olefinic monomers having from 4 to 8 carbon atoms. More preferably, the olefin monomers having from 4 to 8 carbon atoms of this polyolefin are chosen from the group consisting of but-l-ene, but2-ene, 2-methylpropene, pent-l-ene, pent -2-ene, 2-methyl-1-butene, 2-methyl2-butene, 3-methyl-1-butene, hex-1-ene, 4-methyl-1-pentene, 3- methyl-1-pentene hept-1-ene, and oct-1-ene and the mixture of these olefinic monomers.

Preferably, the composition of the self-sealing layer can also comprise various additives, such as for example at least one diene elastomer, a reinforcing or non-reinforcing filler, etc. These additives have been described above. They are present in small quantities (preferably at rates less than 10 pce).

A particularly preferred self-sealing layer which can be used in the laminate in accordance with the invention is a layer consisting of a composition based on at least one styrenic saturated styrenic thermoplastic elastomer, a polyolefin having an average molar mass of Mn number ranging from 10,000 to 550,000 g / mol and at least 140 phr of an extension oil having a mass having an average mass in Mn number less than or equal to 5000 g / mol. This self-sealing layer advantageously has improved self-sealing properties, whatever the shape of the perforating object, compared to the self-sealing compositions consisting of a triblock saturated styrenic elastomer and of an extension oil. . A piercing object is a tapered object with smooth walls or else with a wall having a net.

• Function of the self-sealing layer The self-sealing layer usable in the multi-layer laminate according to the invention consists of a relatively flexible elastomeric composition which can easily creep in order to close a perforation which has taken place in an object pneumatic and restore the tightness of this object.

This self-sealing layer when it is deposited on the internal wall of a pneumatic object thus avoids a loss of pressure following a perforation by a tapered object. In other words, the self-sealing layer when placed in a pneumatic object, such as a tire, has anti-puncture properties. It serves as a puncture protection layer.

The self-sealing properties of the self-sealing layer can be evaluated by any usual technique known to a person skilled in the art, in particular by a test of the resistance to a pressure loss as described in general. of document W02013 / 121019A1.

• Thickness of the self-sealing layer [00166] Those skilled in the art will, in the light of this description, adjust the thickness of the self-sealing layer according to the intended application.

Preferably, the laminate according to the invention comprises at least one self-sealing layer having a thickness greater than or equal to 2 mm. [00168] Preferably, the laminate according to the invention comprises at least one self-sealing layer having a thickness in a range from 2 to 6 mm.

The thickness of the self-sealing layer is measured according to the method described above.

□ Bonding layer As indicated above, the laminate according to the invention comprises at least one bonding layer consisting of a composition based on at least one thermoplastic elastomer A styrenic, at least one thermoplastic elastomer B polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 phr of an extension oil having a number average mass Mn less than or equal to 5000 g / mol.

• Constitution of the bonding layer [00171] At least one styrenic thermoplastic elastomer A as defined above is used in the bonding layer, with all the structural and chemical preferences of the thermoplastic and elastomeric blocks expressed previously.

Preferably, the styrenic thermoplastic elastomer A usable in the compositions of the bonding layer is chosen from the group consisting of saturated styrenic thermoplastic elastomers and mixtures of these elastomers.

Preferably, the styrenic thermoplastic elastomer A which can be used in the compositions of the bonding layer of the multilayer laminate according to the invention is a copolymer of which the elastomer part is saturated, and comprising styrenic blocks and alkylene blocks. The alkylene blocks are preferably ethylene, propylene or butylene.

Preferably, the styrenic thermoplastic elastomer A saturated with the composition of the binding layer is chosen from the group consisting of styrene / ethylene / butylene (SEB) copolymers, styrene / ethylene / propylene (SEP) copolymers, styrene / ethylene / ethylene / propylene copolymers (SEEP), styrene / ethylene / butylene / styrene copolymers (SEBS), styrene / ethylene / propylene / styrene (SEPS), styrene / ethylene / ethylene / propylene / styrene copolymers (SEEPS) and mixtures of these copolymers.

Preferably, the saturated styrenic thermoplastic elastomer A of the composition of the bonding layer is chosen from the group consisting of saturated triblock styrenic thermoplastic elastomers and mixtures of these elastomers.

Even more preferably, the styrenic thermoplastic elastomer A which can be used in the compositions of the bonding layer of the multilayer laminate according to the invention is a copolymer of which the elastomer part is saturated, and comprising three blocks: two styrenic blocks and one alkylene block. The alkylene blocks are preferably ethylene, propylene or butylene.

Preferably, the triblock styrenic thermoplastic elastomer A saturated with the composition of the composition of the binding layer is chosen from the group consisting of styrene / ethylene / butylene / styrene copolymers (SEBS), styrene / ethylene copolymers / propylene / styrene (SEPS) and mixtures of these copolymers.

Preferably, the styrenic thermoplastic elastomer A, in particular saturated, and in particular triblock, of the composition of the binding layer has a number-average molar mass Mn is less than or equal to 500,000 g / mol.

Preferably, the styrenic thermoplastic elastomer A, in particular saturated, and in particular triblock, of the composition of the binding layer has a number-average molar mass Mn lying in a range from 30,000 to 500,000 g / mol, preferably from 40,000 to 400,000 g / mol, more preferably still 50,000 to 300,000 g / mol.

Those skilled in the art will, in the light of the description and of the exemplary embodiments which follow, adjust the quantity of styrenic thermoplastic elastomer A in the composition of the bonding layer according to the particular conditions of use of the bonding layer, in particular as a function of the laminate in which it is intended to be used.

Preferably, the level of styrenic thermoplastic elastomer A, in particular saturated, and in particular triblock, in the composition of the bonding layer is greater than or equal to 10 phr, preferably is included in a range ranging from 20 to 80 phr, preferably is included in a range from 25 to 75 phr.

Examples of these commercially available styrenic, in particular saturated, and in particular triblock, thermoplastic A styrenic elastomers, there may be mentioned the elastomers of the SEPS, SEEPS or SEBS type sold by the company Kraton under the name "Kraton G" ( eg G1650, G1651, G1654, G1730) or the company Kuraray under the name "Septon" (eg "Septon 2007", "Septon 4033", "Septon 8004").

As described above, the composition of the bonding layer comprises at least one (that is to say one or more) thermoplastic elastomer B with polyisobutylene block.

The thermoplastic elastomer B with polyisobutylene block of the bonding layer is a thermoplastic elastomer (abbreviated to "TPE"). TPEs have an intermediate structure between thermoplastic polymers and elastomers. These are block copolymers, made up of rigid, thermoplastic blocks, connected by flexible, elastomeric blocks.

The thermoplastic elastomer B with polyisobutylene block is different from the thermoplastic elastomer A styrenic. By "different from the thermoplastic elastomer

A ”is understood in the sense of the present invention, that the thermoplastic elastomer A styrenic and the thermoplastic elastomer B with polyisobutylene block do not have the same microstructure. They can in particular have flexible elastomer blocks of different chemical nature and / or thermoplastic block sequences of different chemical nature.

Structure of the thermoplastic elastomer B with a polyisobutylene block [00186] The number-average molecular mass (denoted Mn) of the thermoplastic elastomer B with a polyisobutylene block is preferably less than or equal to 500,000 g / mol. More preferably, it is included in a range from 30,000 to 500,000 g / mol, more preferably from 40,000 to 400,000 g / mol. Below the minima indicated, the cohesion between the elastomer chains of the thermoplastic elastomer B with polyisobutylene block, in particular because of its possible dilution (in the presence of an extension oil), is likely to be affected; on the other hand, an increase in the temperature of use risks affecting the mechanical properties, in particular the properties at break, with the consequence of a reduced performance "when hot". Furthermore, an excessively high mass Mn can be penalizing for the implementation. Thus, it has been found that a value within a preferred range ranging from 40,000 to 300,000 g / mol is particularly well suited, in particular to a use of the thermoplastic elastomer B with polyisobutylene block in a composition of a bonding layer.

The number-average molar mass (Mn), the weight-average molar mass (Mw) and the polydispersity index (Ip) of the thermoplastic elastomer B with polyisobutylene block are determined in known manner, by chromatography of steric exclusion (SEC) triple detection as described above.

The value of the polydispersity index Ip (reminder: Ip = Mw / Mn with Mw average molar mass by weight and Mn average molar mass by number) of the thermoplastic elastomer B with polyisobutylene block is preferably less than 3 ; more preferably less than 2 and even more preferably less than 1.5.

In known manner, the TPEs have two glass transition temperature peaks Tg, the lowest temperature being relative to the elastomer part of the TPE, and the highest temperature being relative to the thermoplastic part of the TPE. Thus, the flexible blocks of TPEs are defined by a Tg lower than ambient temperature (25 ° C), while the rigid blocks have a Tg greater than 80 ° C.

In the present application, when reference is made to the glass transition temperature of the TPE, it is the Tg relating to the elastomer block. The TPE preferably has a Tg which is preferably less than or equal to 25 ° C, more preferably less than or equal to 10 ° C. A Tg value higher than these minimums can reduce the performance of the bonding layer when used at very low temperatures; for such use, the Tg of the TPE is more preferably still less than or equal to -10 ° C. Also preferably, the Tg of the TPE is greater than -100 ° C.

To be both elastomeric and thermoplastic in nature, the TPE must be provided with sufficiently incompatible blocks (that is to say different due to their mass, their polarity or their respective Tg) to keep their specific properties of elastomeric or thermoplastic block.

The TPEs can be copolymers with a small number of blocks (less than 5, typically 2 or 3), in which case these blocks preferably have high masses, greater than 15000 g / mol. These TPEs can be, for example, diblock copolymers, comprising a thermoplastic block and an elastomer block. They are also often triblock elastomers with two rigid segments connected by a flexible segment. The rigid and flexible segments can be arranged linearly, in a star or branched. Typically, each of these segments or blocks often contains at least more than 5, generally more than 10 base units.

The TPEs can also include a large number of smaller blocks (more than 30, typically from 50 to 500), in which case these blocks preferably have low masses, for example from 500 to 5000 g / mol, these TPE will be called multiblock TPE afterwards, and are a chain of elastomeric blocks - thermoplastic blocks.

In a first variant, the thermoplastic elastomer B with polyisobutylene block is in a linear form. For example, the thermoplastic elastomer B with a polyisobutylene block is a diblock copolymer: thermoplastic block / elastomer block. The thermoplastic elastomer B with polyisobutylene block can also be a triblock copolymer: thermoplastic block / elastomer block / thermoplastic block, that is to say a central elastomer block and two terminal thermoplastic blocks, at each of the two ends of the elastomer block . Also, the thermoplastic elastomer B with a polyisobutylene multiblock block can be a linear sequence of elastomer blocks - thermoplastic blocks.

Preferably, the thermoplastic elastomer B with a polyisobutylene block of the composition of the bonding layer is a diblock thermoplastic elastomer.

According to another variant of the invention, the thermoplastic elastomer B with a polyisobutylene block useful for the purposes of the invention is in a star form with at least three branches. For example, the thermoplastic elastomer B with a polyisobutylene block can then consist of a star-shaped elastomer block with at least three branches and a thermoplastic block, located at the end of each of the branches of the elastomer block. The number of branches of the central elastomer can vary, for example from 3 to 12, and preferably from 3 to 6.

According to another variant of the invention, the thermoplastic elastomer B with polyisobutylene block is in a branched or dendrimer form. The thermoplastic elastomer B with polyisobutylene block can then consist of a branched elastomer block or dendrimer and of a thermoplastic block, located at the end of the branches of the dendrimer elastomer block.

Nature of the Elastomeric Blocks of the Thermoplastic Elastomer B with a Polyisobutylene Block The elastomeric blocks of the thermoplastic elastomer B with a polyisobutylene block for the purposes of the invention may be any of the polyisobutylene blocks known to those skilled in the art. art.

Preferably, the polyisobutylene block of the thermoplastic elastomer B with a polyisobutylene block is mainly composed of units derived from isobutylene monomer. By predominantly, is meant a content by weight of isobutylene monomer relative to the total weight of the highest polyisobutylene block, and preferably a content by weight of more than 50%, more preferably more than 75%, and for example more than 85 % by weight of the polyisobutylene block.

Preferably, the polyisobutylene block of the thermoplastic elastomer B with polyisobutylene block of the composition of the bonding layer has a weight ratio in units derived from the isobutylene monomer greater than or equal to 85% by weight relative to the weight of the polyisobutylene block .

The polyisobutylene block the thermoplastic elastomer B with a polyisobutylene block can also advantageously also comprise a proportion of units derived from one or more conjugated diene monomers inserted into the polymer chain of the polyisobutylene block preferably ranging up to 10% by weight relative to the weight of the polyisobutylene block. Above 10% by weight, a decrease in the resistance to thermooxidation and to ozone oxidation of the composition of the bonding layer can be observed.

The conjugated dienes which can be copolymerized with isobutylene to form the polyisobutylene block of the thermoplastic elastomer B are conjugated dienes of C4-C14. Preferably, these conjugated dienes are chosen from isoprene, butadiene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-l, 3- butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl1,3-pentadiene, 4-methyl-1,3-pentadiene, 2,3-dimethyl-1,3 -pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,334 hexadiene, 5-methyl-1,3 -hexadiene, 2,3-dimethyl-1,3-hexadiene, 2,4-dimethyl-1,3-hexadiene, 2,5-dimethyl-1,3-hexadiene, 2-neopentylbutadiene, 1,3- cyclopentadiene, 1,3-cyclohexadiene, 1-vinyl-1, 3-cyclohexadiene or a mixture thereof. More preferably, the conjugated diene is isoprene or a mixture containing isoprene.

The polyisobutylene block, according to an advantageous aspect of an object of the invention, can be halogenated and contain halogen atoms in its chain. This halogenation improves the compatibility of the composition of the bonding layer with the other adjacent elements constituting the laminate according to the invention. Halogenation is carried out using bromine or chlorine, preferably bromine, on the units derived from conjugated dienes of the polymer chain of the polyisobutylene block. Only part of these units react with halogen.

Preferably, the polyisobutylene block of the thermoplastic elastomer B with polyisobutylene block has a number-average molecular mass (“Mn”) ranging from 20,000 g / mol to 350,000 g / mol, preferably 25,000 g / mol to 250,000 g / mol so as to confer on said thermoplastic elastomer good elastomeric properties and sufficient mechanical strength compatible with the application of a composition of a bonding layer in a multilayer laminate.

The polyisobutylene block can also be made up of several polyisobutylene elastomer blocks as defined above.

Nature of the thermoplastic blocks of the thermoplastic elastomer B with a polyisobutylene block [00206] The glass transition temperature (Tg) characteristic of the rigid thermoplastic block will be used for the definition of thermoplastic blocks. This characteristic is well known to those skilled in the art. It allows in particular to choose the temperature of industrial implementation (transformation). In the case of an amorphous polymer (or polymer block), the processing temperature is chosen to be substantially higher than the Tg. In the specific case of a semi-crystalline polymer (or polymer block) , one can observe a melting temperature then higher than the glass transition temperature. In this case, it is rather the melting temperature (Tf) which makes it possible to choose the processing temperature of the polymer (or polymer block) considered. So, later, when we talk about "Tg (or Tf, if applicable)", it will be necessary to consider that this is the temperature used to choose the processing temperature.

For the purposes of the invention, the thermoplastic elastomers B with polyisobutylene block comprise one or more thermoplastic block (s), preferably a thermoplastic block, preferably having a Tg (or Tf, where appropriate) greater than or equal to 80 ° C and made up of polymerized monomers. Preferably, this thermoplastic block has a Tg (or Tf, if applicable) comprised in a range varying from 80 ° C to 250 ° C. Preferably, the Tg (or Tf, if applicable) of this thermoplastic block is preferably from 80 ° C to 200 ° C, more preferably from 80 ° C to 180 ° C.

Preferably, the thermoplastic elastomer B with a polyisobutylene block of the composition of the bonding layer comprises, at at least one of the ends of the polyisobutylene block, a thermoplastic block whose glass transition temperature Tg is greater than or equal to 80 ° C.

The proportion of the thermoplastic blocks relative to the thermoplastic elastomer B with a polyisobutylene block, as defined for the implementation of the invention, is determined on the one hand by the thermoplastic properties that said copolymer must have. The thermoplastic blocks having a Tg (or Tf, where appropriate) greater than or equal to 80 ° C. are preferably present in sufficient proportions to preserve the thermoplastic nature of the elastomer according to the invention. The minimum level of thermoplastic blocks having a Tg (or Tf, if applicable) greater than or equal to 80 ° C. in the TPE can vary depending on the conditions of use of the copolymer.

Thermoplastic blocks having a Tg (or Tf, if applicable) greater than or equal to 80 ° C can be made from polymerized monomers of various kinds, in particular, they can constitute the following blocks or their mixtures:

polyolefins (polyethylene, polypropylene) polyurethanes;

polyamides;

polyesters;

polyacetals;

polyethers (polyethylene oxide, polyphenylene ether);

phenylene polysulfides;

polyfluorinated (FEP, PF A, ETFE);

polystyrenes (detailed below);

polycarbonates;

polysulfones;

polymethylmethacrylate polyetherimide.

Thermoplastic blocks having a Tg (or Tf, if applicable) greater than or equal to 80 ° C can also be obtained from monomers chosen from the following compounds and their mixtures:

acenaphthylene: those skilled in the art may for example refer to the article by Z. Fodor and J.P. Kennedy, Polymer Bulletin 1992 29 (6) 697-705;

Tindene and its derivatives such as for example 2-methylindene, 3methylindene, 4-methylindene, dimethylindene, 2-phenylindene, 3-phenylindene and 4-phenylindene; those skilled in the art may for example refer to patent document US4946899, by the inventors Kennedy, Puskas, Kaszas and Hager and to the documents JE Puskas, G. Kaszas, JP Kennedy, WG Hager Journal of Polymer Science Part A: Polymer Chemistry (1992) 30, 41 and JP Kennedy, N. Meguriya, B. Keszler, Macromolecules (1991) 24 (25), 6572-6577;

isoprene, then leading to the formation of a number of 1,4-trans polyisoprene units and of cyclized units according to an intramolecular process; those skilled in the art may for example refer to the documents G. Kaszas, J.E. Puskas, .P. Kennedy Applied Polymer Science (1990) 39 (1) 119-144 and J.E. Puskas, G. Kaszas, J.P. Kennedy, Macromolecular Science, Chemistry A28 (1991) 65-80.

Preferably, the thermoplastic elastomer B with polyisobutylene block of the composition of the bonding layer comprises, at at least one of the ends of the polyisobutylene block, a styrenic thermoplastic block.

Preferably, the thermoplastic elastomer B with polyisobutylene block of the composition of the bonding layer is chosen from the group consisting of thermoplastic copolymers with polystyrene and polyisobutylene blocks and mixtures of these copolymers.

The polystyrene blocks are obtained from styrenic monomers. By styrenic monomer should be understood in the present description any monomer comprising styrene, unsubstituted as substituted; among the substituted styrenes, mention may be made, for example, of methylstyrenes (for example To-methylstyrene, m-methyl styrene or p-methyl styrene, T alpha-methyl styrene, Talpha-2-dimethyl styrene, T alpha-4-dimethyl styrene or diphenylethylene), para-tertiobutylstyrene, chlorostyrenes (for example o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene or 2,4,6- trichlorostyrene), bromostyrenes (for example To-bromostyrene, m-bromostyrene, p-bromostyrene, 2,4-dibromostyrene, 2,6-dibromostyrene or 2,4,6-tribromostyrene) (fluorostyrenes example To-fluorostyrene, m-fluorostyrene, p-fluorostyrene, 2,4-difluorostyrene, 2,6-difluorostyrene or 2,4,6-trifluorostyrene) or also para-hydroxy-styrene.

Preferably, the thermoplastic block of the thermoplastic elastomer B with polyisobutylene block of the composition of the bonding layer comprises units derived from a monomer chosen from the group consisting of styrene, methylstyrenes, para-tertiobutylstyrene, chlorostyrenes, bromostyrenes, fluorostyrenes, para-hydroxy-styrene, and mixtures of these monomers.

According to a preferred embodiment of the invention, the weight content of styrenic monomers (preferably styrene monomers) in the thermoplastic elastomer B with polyisobutylene block is between 5% and 50%. Below the minimum indicated, the thermoplastic nature of the thermoplastic elastomer B with a polyisobutylene block may decrease significantly while above the recommended maximum, the elasticity of the composition of the bonding layer may be affected. For these reasons, the weight content of styrene monomers (preferably styrene monomers) is more preferably between 10% and 40%.

According to a variant of the invention, the polymerized monomer (preferably styrene monomer, more preferably styrene monomer) as defined above can be copolymerized with at least one other monomer so as to form a thermoplastic block having a Tg (or Tf, if applicable) as defined above.

By way of illustration, this other monomer (co-monomer) capable of copolymerizing with the polymerized monomer (preferably styrene monomer, more preferably styrene monomer), can be chosen from diene monomers, more particularly, diene monomers conjugates having 4 to 14 carbon atoms.

As diene co-monomer, the C4-C14 conjugated dienes are especially suitable. In this case, these are random copolymers. Preferably, these conjugated dienes are chosen from isoprene, butadiene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-l, 3- butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3pentadiene, 2,3-dimethyl-1,3 -pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,3-hexadiene, 5-methyl-1, 3-hexadiene, 2,3-dimethyl-1,3-hexadiene, 2,4-dimethyl-1,3-hexadiene, 2,5-dimethyl-1,3hexadiene, 2-neopentylbutadiene, 1,3 -cyclopentadiene, 1,3-cyclohexadiene, l-vinyl-1,3-cyclohexadiene or a mixture thereof. More preferably, the conjugated diene is isoprene or a mixture containing isoprene.

According to the invention, the thermoplastic blocks of the thermoplastic elastomer B with polyisobutylene block have in total, a number average molecular mass ("Mn") ranging from 5000 g / mol to 150,000 g / mol, so as to confer to thermoplastic elastomer B with polyisobutylene block of good elastomeric properties and sufficient mechanical strength and compatible with the use in a composition of a bonding layer for a laminate.

The thermoplastic block can also be made up of several thermoplastic blocks as defined above.

Examples of Thermoplastic B Elastomers with Polyisobutylene Block [00222] Thermoplastic B elastomers with polyisobutylene block are well known to those skilled in the art and are commercially available.

Preferably, the thermoplastic elastomer B with a polyisobutylene block which can be used in the composition of the bonding layer is a copolymer, the elastomer part of which is a polyisobutylene block and the thermoplastic part of which comprising styrenic blocks. Even more preferably, this thermoplastic elastomer B with polyisobutylene block is chosen from the group consisting of diblock thermoplastic elastomers with polyisobutylene block and with styrenic block.

Preferably, the polyisobutylene block thermoplastic elastomer B of the composition of the bonding layer is chosen from the group consisting of styrene / isobutylene diblock copolymers (abbreviated to “SIB”) and mixtures of these copolymers.

Preferably, the level of thermoplastic elastomer B with polyisobutylene block in the composition of the bonding layer is greater than or equal to 10 phr, preferably is within a range ranging from 20 to 80 phr, preferably from 25 to 75 pce.

Thermoplastic elastomers B with polyisobutylene block are commercially available, sold for example with regard to SIBs by the company KANEKA under the name "SIBSTAR" (e.g. "Sibstar 042D" for SIBs). They have for example been described, as well as their synthesis, in patent documents EP 731,112, US 4,946,899, US 5,260,383.

In the composition of the bonding layer, at least 140 phr of an extension oil having a mass having a number average mass Mn of less than or equal to 5000 g / mol is used; the extension oil being as defined above, including with chemical preferences, etc.

Preferably, the oil for extending the composition of the binding layer is chosen from the group consisting of polyolefin oils, paraffinic oils, naphthenic oils, aromatic oils, mineral oils, and mixtures of these oils.

Preferably, the oil for extending the composition of the binding layer is chosen from the group consisting of polyolefin oils, paraffin oils and mixtures of these oils.

Preferably, the oil for extending the composition of the binding layer is a polyolefin oil chosen from the group consisting of polybutene oils and mixtures of these oils.

Preferably, the oil for extending the composition of the binding layer is chosen from the group consisting of polyisobutylene oils and mixtures of these oils.

Preferably, the extension oil of the composition of the binding layer has a number-average molar mass Mn of the extension oil is within a range ranging from 300 to 5000 g / mol, preferably from 350 to 3000 g / mol.

Those skilled in the art will, in the light of the description and of the exemplary embodiments which follow, adjust the amount of extension oil as a function of the particular conditions of use of the bonding layer, in particular as a function of the pneumatic object in which the laminate is intended to be used.

Preferably, the amount of extension oil in the composition of the bonding layer is within a range from 145 and 500 phr, preferably from 145 to 400 phr, more preferably from 145 to 350 phr.

Preferably, the composition of the bonding layer can also comprise various additives, such as for example at least one diene elastomer, a reinforcing or non-reinforcing filler, etc. These additives have been described above. They are present in small quantities (preferably at rates less than 10 pce).

• Thickness [00236] Preferably, the laminate according to the invention comprises a bonding layer having a thickness less than or equal to 1.5 mm.

Preferably, the laminate according to the invention comprises a bonding layer having a thickness lying in a range from 0.05 to 0.5 mm.

The thickness of the bond layer is measured according to the method described above.

• Function [00239] The bonding layer of the laminate according to the invention is a layer located between the layer which is impermeable to inflation gases and the self-sealing layer, (possibly if a film of release agents is present on the surface. of the inflation gas tight layer, the tie layer is a layer located between said film and the self-sealing layer).

Surprisingly, compared with the compositions of the prior art, this bonding layer promotes adhesion between a self-sealing layer and a layer which is impermeable to inflation gases, in particular crosslinked.

Thanks to the specific combination of at least one styrenic thermoplastic elastomer, at least one thermoplastic elastomer B with a specific polyisobutylene block and at least one specific extension oil at a high rate, it has been possible to adhere a self-sealing composition on an elastomeric layer impermeable to inflation gases which has in particular been previously vulcanized. This result can potentially be explained by the accounting of the three constituents of the composition of the binding layer with the constituents of the other two compositions of the adjacent layers; these three constituents forming a bonding layer having a certain tackifying power favoring the assembly of the self-sealing layer with the layer impermeable to inflation gases, in particular when the latter is crosslinked.

3.2. - Method for preparing the laminate and its use Another object of the present invention relates to the use of a bonding layer for fixing a self-sealing layer on a layer that is impermeable to inflation gases, in which:

said bonding layer consists of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 pce of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol, said inflation gas tight layer consists of a composition based on at least one diene elastomer and on at least one crosslinking system, the level of diene elastomer being within a range from 50 to 100 phr; and the self-sealing layer consists of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5,000 g / mol; the content of styrenic thermoplastic elastomer being in a range from 50 to 100 phr.

According to a preferred embodiment of the use, the airtight inflation gas layer is a crosslinked layer.

According to a preferred embodiment of the use, the inflation gas tight layer has on its surface a film of release agents.

According to a preferred embodiment of the use, the inflation gas tight layer constitutes the internal wall of a pneumatic object, such as for example a pneumatic tire.

The preferred embodiments of the bonding layer, the inflation gas tight layer and the self-sealing layer which have been described above also apply to the use described above.

Another object of the present invention relates to a method of fixing a self-sealing layer on the internal wall of a pneumatic object, said self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol; the level of said styrenic thermoplastic elastomer being within a range from 50 to 100 phr, process in which:

(A) there is a pneumatic object, the internal wall of which is made of a gaseous inflation gas layer consisting of a composition based on at least one diene elastomer and at least one crosslinking system, the rate diene elastomer being included in a range from 50 to 100 phr;

(b) applying a bonding layer on said internal wall;

(c) applying said self-sealing layer on said bonding layer, said bonding layer consisting of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol.

[00248] At the end of the process, a laminate is obtained which can be used in a pneumatic object.

Preferably, the inflation gas tight layer has on its surface a film of release agents.

This method is applicable to any type of pneumatic object and is particularly advantageous when it is desired to install a self-sealing layer (puncture protection layer) after the curing of a pneumatic tire.

Preferably in the process, the pneumatic object is a pneumatic tire.

The internal wall of a pneumatic object is the wall which is in contact with the inflation gas or gases.

The preferred embodiments of the bonding layer, the inflation gas tight layer and the self-sealing layer which have been described above also apply to this fixing method.

In the first step of the method, there is a pneumatic object whose internal wall is made of a tight inflation gas layer consisting of a composition based on at least one diene elastomer and at least a crosslinking system, the level of diene elastomer being within a range from 50 to 100 phr. This pneumatic object can be manufactured by any technique well known to those skilled in the art.

For example, when the pneumatic object is a pneumatic tire, the inflation gas tight layer which is not vulcanized (the expressions “uncooked” or “not crosslinked” are equivalent) is deposited on a manufacturing drum, wrapped around this drum and then welded by the usual techniques used in the field of making a pneumatic tire.

More specifically, said inflation gas tight layer is prepared in suitable mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art:

- a first working phase or thermomechanical mixing (sometimes qualified as a “non-productive” phase) at high temperature, up to a maximum temperature between 130 ° C and 200 ° C, preferably between 145 ° C and 185 ° C , followed by a second mechanical working phase (sometimes referred to as a “productive” phase) at a lower temperature, typically below 120 ° C, for example between 60 ° C and 100 ° C, the finishing phase during which incorporated the crosslinking system. Preferably the crosslinking system is a vulcanization system.

According to a preferred embodiment of the invention, all the basic constituents of the compositions of this layer, with the exception of the crosslinking system (preferably the vulcanization system), such as any fillers, are incorporated with intimately, by kneading, with the diene elastomer during the first so-called non-productive phase, that is to say that it is introduced into the mixer and that it is thermomechanically kneaded, in one or more stages , at least these different basic constituents until reaching the maximum temperature between 130 ° C and 200 ° C, preferably between 145 ° C and 185 ° C. The total duration of the kneading, in this non-productive phase, is preferably between 1 and 15 min.

After cooling the mixture thus obtained during the first non-productive phase, the crosslinking system (preferably the vulcanization system) is then incorporated at low temperature, generally in an external mixer such as a cylinder mixer. ; the whole is then mixed (productive phase) for a few minutes, for example between 2 and 15 min.

The final composition thus obtained is then calendered to the desired dimensions, for example in the form of a layer whose thickness has been indicated above. This inflation gas tight layer is then placed on the construction drum.

Then applied successively to this gas-tight inflation layer, all the other usual components of the pneumatic tire according to the usual techniques for manufacturing a pneumatic tire. A pneumatic tire is thus obtained.

In the second step of the fixing method of the invention, the bonding layer is applied to said internal wall, that is to say on the gas tight layer of inflation (or optionally on the film of release agent if present).

The bonding layer can be obtained in the usual way, for example by incorporating the various components in a twin-screw extruder or in a paddle mixer, in particular with Z blades.

In a first way, in particular, a process for obtaining the bonding layer comprises a first step which consists in incorporating the styrenic thermoplastic elastomer A and the extension oil in a twin-screw extruder equipped with a sufficient number of conveying, shearing and retention zones so as to achieve the melting of the elastomer matrix and incorporation of the extension oil. The twin-screw extruder can be any type of twin-screw extruder whose L / D ratio between the length and the diameter of the screw is within a range from 20 to 40, equipped with a hopper for the supply of styrenic thermoplastic elastomer A and at least one pressurized liquid injection pump for the extension oil. At the point of introduction of the styrenic thermoplastic elastomer A, the temperature is close to room temperature (23 ° C). It is then brought further along the screw to a value substantially higher than the melting temperature of the styrenic thermoplastic elastomer A retained and is included in a range from 220 to 290 ° C. At the point of introduction of the extension oil, the temperature is also within a range from 220 to 290 ° C. At the point of exit from the extruder, the temperature is in the range of 110 to 170 ° C. The extruder is provided at its outlet with a die allowing the product to be shaped to the desired dimensions. The overall output flow is in a range from 3 to 10 kg / h.

In a second step, the extrusion product obtained in the previous step and the thermoplastic elastomer B with a polyisobutylene block different from the styrenic thermoplastic elastomer B are introduced using a hopper into a mono extruder. -vis or bis-vis whose L / D ratio between the length and the diameter of the screw is in a range from 10 to 30. The temperature at the point of introduction by the hoppers of the extrusion product previous step and the thermoplastic elastomer B with polyisobutylene block is included in a range from 100 to 180 ° C at the screw inlet. At the screw outlet, the temperature is reduced, which is then in a range from 100 to 150 ° C. The extruder is provided at its outlet with a die making it possible to shape the bonding layer to the desired dimensions.

When using styrenic thermoplastic elastomers such as SEPS or SEBS already extended with high levels of oils, it is then possible to carry out only the second extrusion step to obtain the bonding layer. The already extensive styrenic thermoplastic elastomers are well known and commercially available. By way of examples, mention may be made of the products sold by the company Hexpol TPE under the name "Dryflex" (eg "Dryflex 967100") or "Mediprene" (eg "Mediprene 500000M"), those sold by Multibase under the name "Multiflex "(Eg" Multiflex G00 ").

Another conventional way of obtaining the bonding layer consists in the use of a paddle mixer Z, for example of the type MK LU 1 from the company Linden with a useful capacity of one liter, in which are loaded with the styrenic thermoplastic elastomer A, the extension oil having a mass having a number average mass Mn of less than or equal to 5000 g / mol and the thermoplastic elastomer B with polyisobutylene block different from the thermoplastic elastomer A styrene and any additives. The mixer tank is heated so that the mixture reaches a temperature in the range of 80 to 140 ° C depending on the number of ingredients used. The speed of the blades is selected in a range from 10 to 100 rpm and the mixing time is selected in a range from 30 min to 24 hours. A person skilled in the art knows how to adjust each of these parameters in order to obtain a homogeneous mixture which will then be used as a bonding layer. In this case, a “batch” is obtained which does not exhibit any particular shaping and which will subsequently be calendered to the desired dimensions.

In the third step of the fixing method of the invention, the self-sealing layer is applied to the bonding layer, for example by bringing said self-sealing layer into contact with said bonding layer [00268] The layer Self-sealing can be obtained in the usual way, for example by incorporating the various components in a twin-screw extruder or in a paddle mixer, in particular with Z blades.

In particular, the self-sealing layer can be obtained by implementing the first step of the process for obtaining the bonding layer as described above.

According to a first variant of the fixing method of the invention, the method may include a step (d) in which the pneumatic object obtained at the end of step (c) is baked. According to this variant, the bonding layer and the self-sealing layer are applied to the internal wall of the pneumatic object before curing.

Before baking, this consists of laying the bonding layer as defined above, including its preferred variants, on the gas-tight inflation layer (or internal wall), that is to say applying this layer of in the form of a layer of thickness less than or equal to 1.5 mm on the layer impermeable to non-crosslinked inflation gases, then apply the self-sealing layer on this bonding layer and finally proceed to firing the bandage pneumatic. It may be necessary to protect the self-sealing layer with an anti-sticking layer or a protective film. The anti-sticky layer or the protective film facilitates the manufacture of the tire by limiting direct contact between the anti-puncture layer and the tools for assembling the tire blank or between the anti-puncture layer and the membrane of the tires. cooking presses. These anti-sticky layers or protective films and their use are well known to those skilled in the art.

According to a second preferred variant of the fixing method of the invention, the method may include an intermediate step (a ’) in which the pneumatic object is baked. According to this variant, the bonding layer and the self-sealing layer are applied to the internal wall of the pneumatic object after curing said pneumatic object.

After baking, this consists of laying the bonding layer as defined above (including these preferred embodiments) on the gas-tight inflation layer (or internal wall) already baked (vulcanized, crosslinked). The bonding layer is applied by any suitable means, such as by gluing, spraying or even extruding and blowing a layer of thickness less than or equal to 1.5 mm. Then, the self-sealing layer is applied to the bonding layer by any suitable means, such as by gluing, spraying or even extrusion and blowing a layer of thickness greater than or equal to 2 mm.

According to one embodiment, this laying of the bonding layer can be done on a crosslinked layer impermeable to inflation gases from which the film of release agents will have been previously removed, in particular by scraping or by dissolution with solvents .

According to another embodiment, the laying of the bonding layer, including its preferred versions, can also be done directly on the film of release agents which is located on the surface of the gas-tight layer baked inflation. This embodiment is advantageous since it no longer requires the use of a scraper or solvent to remove the film of release agents. This saves time and security for the manufacturer. Preferably, a bonding layer is therefore deposited on the film of release agents, then the self-sealing layer is deposited on the bonding layer according to techniques well known to those skilled in the art.

The baking step is well known to those skilled in the art and can be carried out according to any technique usually used in the field of manufacturing pneumatic objects (such as pneumatic tires).

The multilayer laminate of the invention can also be prepared independently of the pneumatic object in which it is or will be used. For example, the multilayer laminate is prepared according to the methods known to those skilled in the art, by separately preparing the three layers of the laminate, then by associating the layer which is impermeable to inflation gases, in particular after the latter has been fired, to the bonding layer, then by associating the self-sealing layer with the bonding layer. The association of different layers can be done for example by simple heat treatment, preferably under pressure (for example a few minutes at 150 ° C. at 16 bars).

Another object of the present invention relates to the use of a multilayer laminate according to the invention and its preferred embodiments as the internal wall of a pneumatic object, in particular of a pneumatic tire. The multilayer laminate according to the invention can be used as an internal wall in a pneumatic tire. It thus gives this tire sealing properties to inflation gases and anti-puncture properties. In addition, thanks to the bonding layer, it allows faster and less costly manufacture of said bandage since the self-sealing layer can be applied to the gas-tight inflation layer which has been crosslinked. It thus simplifies the cooking steps.

3.3. - Pneumatic object comprising at least one multilayer laminate [00279] Another object of the present invention relates to a pneumatic object comprising a laminate as defined above, including its preferred embodiments. Preferably, said laminate, including its preferred embodiments, constitutes the internal wall of said pneumatic object.

Preferably, the pneumatic object comprising a multilayer laminate according to the invention is a pneumatic tire, in particular intended to equip vehicles. These vehicles can be passenger-type motor vehicles, SUVs (“Sports Utility Vehicles”), two-wheelers (especially motorcycles), airplanes, such as industrial vehicles chosen from vans, “Heavy goods vehicles” - this is i.e. metro, bus, road transport equipment (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles -, other transport or handling vehicles.

The pneumatic object can be manufactured by any technique well known to those skilled in the art.

4. - EXAMPLE The examples which follow illustrate the invention without however limiting it.

The following different layers are prepared which are then assembled to form a laminate whose adhesion property of the bonding layer will be tested by a peel test.

4.1. - Layer impervious to inflation gases [00284] The layers which are impermeable to inflation gases consist of either composition C1 or composition C2.

4.1.1. - Formulation of the layer impermeable to inflation gases The formulations of compositions Cl and C2 are provided in Table I.

The rates are expressed in pce.

Table I

Composition Cl C2 Brominated butyl rubber (a) 100 100 Carbon black (b) 50 50 Calcium carbonate 10 (-) Zinc oxide 1.5 1.5 Stearic acid 1.5 1.5 Sulfur 1.5 1.5 Accelerator (c) 1.5 1.5

(a) Brominated butyl rubber sold under the reference Bromobutyle 7211 by the company ExxonMobil;

(b) N772 carbon black sold by Cabot Corporation;

(c) Mercaptobenzothiazyl disulfide sold under the reference MBTS-MG by the company Akrochem.

4.1.2. - Preparation of the airtight layer for inflation gases The airtight layers for inflation gas are prepared according to the following process.

Is introduced into an internal mixer, filled to 70% and whose initial tank temperature is about 60 ° C, successively carbon black, butyl rubber and various other possible ingredients with the exception of the system vulcanization. Thermomechanical work (non-productive phase) is then carried out in one step, which lasts a total of approximately 3 to 4 minutes, until a maximum "fall" temperature of 150 ° C is reached.

The mixture thus obtained is recovered, it is cooled and then sulfur and the accelerator are incorporated on an external mixer (homo-finisher) at 30 ° C., mixing the whole (productive phase) for an appropriate time (by example between 5 and 12 min).

The composition obtained at the end of the productive phase is then calendered either in the form of thin sheets of length 150 mm, width 150 mm and thickness 2 mm, then it is cooked for 13 min at 180 ° C under pressure of ten bars.

4.2. - Bonding layer The bonding layers are made up either of composition T, or of composition 5 Al.

4.2.1. - Formulation of the bonding layer The formulations of compositions T and Al are provided in Table II. The rates are expressed in pce.

Composition T constitutes the bonding layer of the laminate representative of 10 of the prior art W02009 / 156049.

The composition Al constitutes the bonding layer of the laminate according to the invention.

Table II:

Composition T al GST (a) 100 (-) GST (b) (-) 57 Polyisobutylene block thermoplastic elastomer (c) (-) 43 Extension oil (d) (-) 326

(a) Styrene thermoplastic elastomer (TPS): styrene / polyisoprene / styrene block copolymer SIS sold by the company Kraton under the reference DI 161;

Mn = 220,000 g / mol and Ip = 1.3; Mn and Ip measured according to the method described in the description.

(b) Styrenic thermoplastic elastomer (TPS): styrene / ethylene / butylene / styrene block copolymer SEBS sold by the company Kraton under the reference G1654;

Mn = 116,000 g / mol and Ip = 1.1; Mn and Ip measured according to the method described in the description.

(c) Thermoplastic elastomer B with polyisobutylene block: styrene / polyisobutylene diblock copolymer sold by the company Kaneka under the reference Sibstar 042; Mn = 40,000 g / mol, Ip = 1.2; Mn and Ip measured according to the method described in the description.

(d) Extension oil: Polyisobutylene oil sold by the company Univar under the reference Dynapak 190; Mn = 1000 g / mol and Ip = 1.4;

4.2.2. - Preparation of the bonding layer • Preparation of the bonding layer consisting of composition T [00296] The styrenic thermoplastic elastomer (SIS) is placed in a mold containing a shim of the desired thickness. The whole is placed in an electric plate press of the CARVER brand to obtain the film by melting said elastomer and molding, ie at a temperature of 150 ° C. for 10 min and under 8 bar of pressure.

Preparation of the bonding layer consisting of the composition Al or A2 The bonding layer consisting of the composition Al is prepared in a conventional manner by two-stage extrusion of the thermoplastic elastomer A of styrene, of the oil. extension and of the thermoplastic elastomer B with polyisobutylene block.

In the first step, the thermoplastic elastomer A styrenic and the extension oil are introduced into a twin-screw extruder L / D = 40 via a feed hopper for said elastomer and a liquid injection pump under pressure for said extension oil. The twin-screw extruder is provided with a flat die allowing the product to be extruded to the desired dimensions. The temperature at the point of introduction of the styrenic thermoplastic elastomer is at room temperature (23 ° C). It is then brought further along the screw to a value appreciably higher than the melting temperature of the styrenic thermoplastic elastomer retained, that is to say between 275 ° C. At the point of introduction of the oil, the temperature is also between 275 ° C. At the point of exit from the extruder, the temperature is between 140 ° C. The overall flow is between 4 kg / h at the outlet.

During the second step, the profile obtained by extrusion of the first step and the thermoplastic elastomer B is introduced into a twin-screw extruder L / D = 20 via hoppers. The temperature at the point of introduction by the hoppers of the thermoplastic elastomer B and of the preceding profile comprising the thermoplastic elastomer A styrenic and the extension oil is between 125 ° C. at the inlet of the screw. At the screw outlet, the temperature is lowered between 125 ° C. The flat die at the extruder outlet provides a profile of the following dimensions: length 150 mm, width 150 mm and thickness 2 mm.

4.3. - Self-sealing layer [00300] The self-sealing layer consists of a composition B1.

4.3.1. - Formulation of the self-sealing layer The formulation of composition Bl is provided in Table III. The rates 5 are expressed in pce.

Table III

Composition bl GST (a) 100 Extension oil (b) 570

(a) Styrenic thermoplastic elastomer (TPS): styrene / ethylene / butylene / styrene block copolymer SEBS sold by the company Kraton under the reference G1654; Mn = 116,000 g / mol and Ip = 1.1; Mn and Ip measured according to the method described in the description.

(b) Extension oil: Polyisobutylene oil sold by the company Univar under the reference Dynapak 190; Mn = 1000 g / mol and Ip = 1.4; Mn and Ip measured according to the method described in the description.

4.3.2. - Preparation of the self-sealing layer The self-sealing layer consisting of composition Bl is conventionally prepared by one-step extrusion of the styrenic thermoplastic elastomer and the extension oil.

In the first step, the styrenic thermoplastic elastomer and the extension oil are introduced into a twin-screw extruder L / D = 40 via a feed hopper for the elastomer and a liquid injection pump under pressure for extension oil. The twin-screw extruder is provided with a flat die allowing the product to be extruded to the desired dimensions. The temperature at the point of introduction of the thermoplastic elastomer is at room temperature (23 ° C). It is then brought further along the screw to a value appreciably higher than the melting temperature of the styrenic thermoplastic elastomer retained, that is to say between 275 ° C. At the point of introduction of the oil, the temperature is also between 275 ° C. At the point of exit from the extruder, the temperature is between 140 ° C. The overall flow is between 4 kg / h at the outlet. This extruder is equipped with a flat die which makes it possible to obtain a profile of the following dimensions: length 150 mm, width 150 mm and thickness 2 mm.

4.4. - Making of the laminates / test pieces and peeling test The multilayer laminates are tested for the adhesion of the bonding layer to the crosslinked gas-tight layer according to a so-called peeling test.

The peel test pieces of the 180 ° peel type are produced in the following manner:

A sheet of a vulcanized inflation gas tight layer of dimensions 150 mm by 150 mm and thickness 2 mm is placed on a bonding layer 0.3 mm thick and dimensions 150 mm by 150 mm. On the still available face of the tie layer, a self-sealing layer 3 mm thick and 150 mm by 150 mm in size is applied. A 0.3 mm bonding layer of the same composition as that described above is again applied and again over a sheet of a vulcanized inflation gas tight layer of the same composition as the previous one. On one side of this stack, a rupture initiator is inserted between the sheet of vulcanized inflation gas tight layer and the tie layer. The dimensions of the primer are: width 20 mm and length 150 mm. This stack is placed under a press and a pressure of 0.1-0.2 bar is applied for one minute and at ambient temperature 23 ° C. Peeling test pieces are obtained by cutting strips 30 mm wide and 150 mm long with a guillotine, taking care to have the primer at one end of the test piece.

The two sides of the fracture initiator were then placed in the jaws of an Instron brand traction machine. (Model 5569). The peel measurement is carried out by traction at 180 ° and at a speed of 100 mm / min at temperature at 23 ° C. The tensile forces are recorded and they are normalized by the width of the test piece. A force curve is obtained per unit of width (in N / mm) as a function of the displacement of the mobile cross member of the traction machine (between 0 and 150 mm). The adhesion value adopted corresponds to the initiation of the rupture within the test piece and therefore to the maximum value of this curve.

4.5. - Test The purpose of this test is to demonstrate that a laminate according to the invention has improved adhesion properties compared to the laminate of document W02009 / 156049A1 representative of the prior art. The laminate of the prior art allows adhesion when the self-sealing layer is applied before baking the gas-tight inflation layer and the tire is then cured, but it does not allow the adhesion of the self-sealing layer when this is applied after the tire has been cured.

The STI, SI1 and SI2 multilayer laminates are prepared and a measurement of the adhesion is carried out according to paragraph 4.4. The structure of the laminates and the results of the peel test are presented in Table IV.

The STI laminate not in accordance with the invention is prepared with a cross-linked inflation gas tight layer on which an attempt has been made to deposit the adhesive layer and the self-sealing layer described in document WO2009 / 156049A1.

The SI1 laminate according to the invention differs from the STI laminate not in accordance with the invention by the formulation of the composition of the bonding layer.

The SI2 laminate represents another embodiment of the invention.

The laminate SI2 differs from the laminate SI1 by the different formulation of the composition of the layer impermeable to inflation gases.

Table IV

Laminate ITS SI1 SI2 Compositions used for diapers Cl / T / Bl C1 / A1 / B1 C2 / A1 / B1 Force (N / mm ² ) θ (*) 0.1 0.1

(*): The digital value zero has been assigned to this laminate because the making of the test piece was not possible due to a lack of adhesion of the layers.

According to Table IV, the adhesion of the bonding layer between the self-sealing layer and the inflation gas tight layer in the non-conforming STI laminate is not possible when the gas tight layer of inflation was cross-linked.

Surprisingly, in the laminate SI2 according to the invention (and the other embodiment of the invention) an adhesion of the self-sealing layer on the layer impermeable to inflation gases crosslinked via the bonding layer is observed.

4.6 Example of a tire comprising a multilayer laminate FIG. 1 schematically shows (without respecting a specific scale), a radial section of a pneumatic tire incorporating a laminate according to the invention.

This tire 1 has a crown 2 reinforced by a crown or belt reinforcement 6, two sidewalls 3 and two beads 4, each of these beads 4 being reinforced with a rod 5. The crown 2 is surmounted by a strip bearing not shown in this schematic figure. A carcass reinforcement 7 is wound around the two rods 5 in each bead 4, the reversal 8 of this reinforcement 7 being for example disposed towards the outside of the tire 1 which is here shown mounted on its rim 9. The carcass reinforcement 7 is in a manner known per se consisting of at least one ply reinforced by so-called “radial” cables, for example textile or metal, that is to say that these cables are arranged practically parallel to each other and s' extend from one bead to the other so as to form an angle between 80 ° and 90 ° with the median circumferential plane (plane perpendicular to the axis of rotation of the tire which is located midway between the two beads 4 and goes through the middle of the crown reinforcement 6).

The pneumatic tire 1 is characterized in that its internal wall comprises a multilayer laminate according to the invention as defined above, comprising at least three layers 10a, 10b, 10c, a self-sealing layer 10a such that defined above (including its preferred embodiments); a bonding layer 10b as defined above (including its preferred embodiments) and an inflation gas tight layer 10c as defined above (including its preferred embodiments).

According to a preferred embodiment of the invention, the three layers 10a, 10b, 10c cover substantially the entire inner wall of the tire, extending from one sidewall to the other, at least up to the level the rim hook when the tire is in the assembled position. According to other possible embodiments, the self-sealing layer 10a and the bonding layer 10b could however cover only part of the crosslinked or non-crosslinked zone and impermeable to inflation gases (layer 10c), for example only the crown zone. of the tire or extend at least from the crown zone to the mid-side (equator) of said tire.

According to another preferred embodiment, the laminate is arranged in such a way that the self-sealing layer 10a is radially outermost in the tire, relative to the bonding layer 10b, as shown diagrammatically in FIG. 1 In other words, the self-sealing layer 10a covers the bonding layer 10b on the side of the internal cavity 11 of the tire 1.

The layer 10c leaktight to inflation gases therefore allows swelling and pressure maintenance of the tire 1; its sealing properties allow it to guarantee a relatively low pressure loss rate, making it possible to keep the tire inflated, in normal operating condition, for a sufficient duration, normally several weeks or several months.

The self-sealing layer 10a is disposed between the layer 10b and the cavity 11 of the tire. It provides the tire with effective protection against pressure losses due to accidental punctures, by allowing these perforations to be shut off automatically.

The bonding layer 10b makes it possible to promote adhesion between the layer 10c which is impermeable to the inflation gases and the self-sealing layer 10a, in particular when the layer 10c which is impermeable to the inflation gases is previously crosslinked before the layer is applied. 10a self-sealing.

If a perforating object such as a nail or a screw passes through the structure of the pneumatic object, for example a wall such as a sidewall 3 or the top 6 of the tire 1, the self-sealing layer conforms to the invention serves as a puncture-resistant layer; it is subject to several constraints. In response to these constraints, and thanks to its advantageous properties of deformability and elasticity, said self-sealing layer creates a sealed contact area all around the perforating object. The flexibility of the self-sealing layer allows it to interfere in small openings regardless of the shape of the piercing object. This interaction between the self-sealing layer and the perforating object provides a seal to the area affected by the latter.

In case of accidental or voluntary withdrawal of the piercing object, a perforation remains: it is likely to create a more or less significant leak, depending on its size. The self-sealing layer, subjected to the effect of hydrostatic pressure, is sufficiently flexible and deformable to seal, by deforming, the perforation, preventing the escape of inflation gas. In the case of a pneumatic tire in particular, it has been found that the flexibility of the self-sealing layer makes it possible to withstand the stresses of the surrounding walls without problem, even during the deformation phases of the loaded pneumatic tire and during travel.

Claims (48)

1. Laminate for pneumatic object comprising at least three different and superposed layers: a gas-tight inflation layer consisting of a composition based on at least one diene elastomer and at least one crosslinking system, the level of diene elastomer being in a range from 50 to 100 phr ; - A bonding layer consisting of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 pce of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol; a self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5,000 g / mol; the level of styrenic thermoplastic elastomer being in a range from 50 to 100 phr; and said tie layer being disposed between said inflation gas tight layer and said self-sealing layer. 2. The laminate according to claim 1, in which the diene elastomer of the composition of the gas-tight inflation layer is chosen from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and mixtures of these elastomers. 3. The laminate according to claim 2, in which the diene elastomer of the composition of the gas-tight inflation layer is chosen from the group of isoprene and isobutene copolymers, halogenated copolymers of isoprene and isobutene and mixtures of these copolymers. 4. A laminate according to any one of claims 1 to 3, wherein the composition of the inflation gas tight layer further comprises a reinforcing filler. 5. The laminate according to any of claims 1 to 4, wherein the composition of the inflation gas tight layer further comprises a non-reinforcing filler. 6. Laminate according to any one of claims 1 to 5, in which the styrenic thermoplastic elastomer A of the composition of the binding layer is chosen from the group consisting of saturated styrenic thermoplastic elastomers and mixtures of these elastomers. 7. The laminate according to claim 6, in which the styrenic thermoplastic elastomer A saturated with the composition of the bonding layer is chosen from the group consisting of styrene / ethylene / butylene copolymers, styrene / ethylene / propylene copolymers, copolymers. styrene / ethylene / ethylene / propylene, styrene / ethylene / butylene / styrene copolymers, styrene / ethylene / propylene / styrene copolymers, styrene / ethylene / ethylene / propylene / styrene copolymers and mixtures of these copolymers. 8. The laminate according to claim 6, in which the saturated styrenic thermoplastic elastomer A of the composition of the bonding layer is chosen from the group consisting of saturated triblock styrenic thermoplastic elastomers and mixtures of these elastomers. 9. The laminate according to claim 8, in which the triblock styrenic thermoplastic elastomer A saturated with the composition of the bonding layer is chosen from the group consisting of styrene / ethylene / butylene / styrene copolymers, styrene / ethylene / propylene copolymers. / styrene and mixtures of these copolymers. 10. Laminate according to any one of claims 1 to 9, in which the content of styrenic thermoplastic elastomer A in the composition of the binding layer is greater than or equal to 10 phr, preferably is within a range from 20 to 80 pc, preferably is within a range from 25 to 75 pc. 11. A laminate according to any one of claims 1 to 10, in which the polyisobutylene block of the thermoplastic elastomer B with polyisobutylene block of the composition of the bonding layer has a weight ratio in units derived from the isobutylene monomer greater than or equal to 85% by weight relative to the weight of the polyisobutylene block. 12. Laminate according to any one of claims 1 to 11, in which the thermoplastic elastomer B with polyisobutylene block of the composition of the bonding layer comprises, at at least one of the ends of the polyisobutylene block, a thermoplastic block of which the glass transition temperature Tg is greater than or equal to 80 ° C. 13. A laminate according to any one of claims 1 to 12, in which the thermoplastic elastomer B with polyisobutylene block of the composition of the bonding layer is chosen from the group consisting of thermoplastic copolymers with polystyrene and polyisobutylene blocks and mixtures of these copolymers. 14. The laminate according to claim 13, in which the thermoplastic block of the thermoplastic elastomer B with polyisobutylene block of the composition of the binding layer comprises units derived from a monomer chosen from the group consisting of styrene, methylstyrenes, para- tert-butylstyrene, chlorostyrenes, bromostyrenes, fluorostyrenes, para-hydroxy-styrene, and mixtures of these monomers. 15. The laminate according to claim 14, in which the polyisobutylene block thermoplastic elastomer B of the composition of the bonding layer is chosen from the group consisting of styrene / isobutylene diblock copolymers and mixtures of these copolymers. 16. Laminate according to any one of claims 1 to 15, in which the thermoplastic elastomer B with polyisobutylene block in the composition of the bonding layer is greater than or equal to 10 phr, preferably is within a range from 20 at 80 phr, preferably from 25 to 75 phr. 17. The laminate according to any one of claims 1 to 16, in which the oil for extending the composition of the binding layer is chosen from the group consisting of polyolefin oils, paraffin oils, naphthenic oils, aromatic oils, mineral oils, and mixtures of these oils. 18. The laminate according to claim 17, in which the oil for extending the composition of the binding layer is a polyolefin oil chosen from the group consisting of polybutene oils and mixtures of these oils. 19. The laminate according to claim 18, in which the oil for extending the composition of the binding layer is chosen from the group consisting of polyisobutylene oils and mixtures of these oils. 20. A laminate according to any one of claims 1 to 19, in which the level of extension oil in the composition of the binding layer is within a range from 145 and 500, preferably from 145 to 400, more preferably from 145 to 350 pce. 21. Laminate according to any one of claims 1 to 20, in which the styrenic thermoplastic elastomer of the composition of the self-sealing layer is chosen from the group consisting of saturated styrenic thermoplastic elastomers and mixtures of these elastomers. 22. A laminate according to claim 21, in which the styrenic thermoplastic elastomer saturated with the composition of the self-sealing layer is chosen from the group consisting of styrene / ethylene / butylene copolymers, styrene / ethylene / propylene copolymers, copolymers styrene / ethylene / ethylene / propylene, styrene / ethylene / butylene / styrene copolymers, styrene / ethylene / propylene / styrene copolymers, styrene / ethylene / ethylene / propylene / styrene copolymers and mixtures of these copolymers. 23. Laminate according to any one of claims 1 to 20, in which the styrenic thermoplastic elastomer of the composition of the self-sealing layer is chosen from the group consisting of unsaturated styrenic thermoplastic elastomers and mixtures of these elastomers. 24. The laminate according to claim 23, in which the styrenic thermoplastic elastomer of the composition of the self-sealing layer is chosen from the group consisting of styrene / butadiene copolymers, styrene / isoprene copolymers, styrene / butadiene / butylene copolymers , styrene / butadiene / isoprene copolymers, styrene / butadiene / styrene copolymers, styrene / butadiene / butylene / styrene copolymers, styrene / isoprene / styrene copolymers, styrene / butadiene / isoprene / styrene copolymers and mixtures of these copolymers . 25. A laminate according to any one of claims 1 to 24, which oil for extending the composition of the self-sealing layer is chosen from the group consisting of polyolefin oils, paraffin oils, naphthenic oils, aromatic oils, mineral oils, and mixtures of these oils. 26. The laminate according to claim 25, in which the oil for extending the composition of the self-sealing layer is a polyolefin oil chosen from the group consisting of polybutene oils and mixtures of these oils. 27. The laminate according to claim 26, in which the oil for extending the composition of the self-sealing layer is chosen from the group consisting of polyisobutylene oils and mixtures of these oils. 28. A laminate according to any one of claims 1 to 27, in which the rate of extension oil in the composition of the self-sealing layer is within a range from 140 and 700 phr, preferably from 145 to 600 pce. 29. The laminate according to any one of claims 1 to 28, in which the composition of the self-sealing layer further comprises a polyolefin having a number-average molar mass Mn ranging from 10,000 to 550,000 g / mol, 30. A laminate according to any one of claims 1 to 29, wherein the inflation gas tight layer has a thickness greater than or equal to 0.4 mm. 31. The laminate according to claim 30, wherein the inflation gas tight layer has a thickness in a range from 0.4 to 2 mm, preferably in a range from 0.6 to 1.2 mm. 32. The laminate according to any one of claims 1 to 31, wherein the bonding layer has a thickness less than or equal to 1.5 mm. 33. The laminate of claim 32, wherein the tie layer has a thickness in the range of 0.05 to 0.5 mm. 34. Laminate according to any one of claims 1 to 33, in which the self-sealing layer has a thickness greater than or equal to 2 mm. 35. The laminate of claim 34, wherein the self-sealing layer has a thickness in the range of 2 to 6 mm. 36. Laminate according to any one of claims 1 to 35, in which the gas-tight inflation layer has on its surface a film of release agents. 37. The laminate according to any one of claims 1 to 36, wherein the inflation gas tight layer is crosslinked. 38. Use of a laminate as defined in any one of claims 1 to 37 as internal wall of a pneumatic object, in particular of a pneumatic tire. 39. A pneumatic object comprising a laminate as defined in any one of claims 1 to 38. 40. A pneumatic object according to claim 39, characterized in that it is a pneumatic tire. 41. Use of a tie layer to fix a self-sealing layer on a gas-tight inflation layer, in which: said tie layer consists of a composition based on at least one styrenic thermoplastic elastomer A of at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 phr an extension oil having a number average mass Mn of less than or equal to 5000 g / mol, said layer which is impermeable to inflation gases consists of a composition based on at least one diene elastomer and at least a crosslinking system, the level of diene elastomer being within a range from 50 to 100 phr; and the self-sealing layer consists of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol; the content of styrenic thermoplastic elastomer being in a range from 50 to 100 phr. 42. Use according to claim 41, in which the gaseous inflation gas layer is crosslinked. 43. Use according to claim 41 to 42 in the gas-tight inflation layer constitutes the inner wall of a pneumatic object, such as for example a pneumatic tire. 44. Method for fixing a self-sealing layer on the internal wall of a pneumatic object, said self-sealing layer consisting of a composition based on at least one styrenic thermoplastic elastomer and at least 140 phr an extension oil having a number average mass Mn of less than or equal to 5000 g / mol; the level of styrenic thermoplastic elastomer being within a range from 50 to 100 phr, process in which: (A) there is a pneumatic object, the internal wall of which is made of a gaseous inflation gas layer consisting of a composition based on at least one diene elastomer and at least one crosslinking system, the rate diene elastomer being included in a range from 50 to 100 phr; (b) applying a bonding layer on said internal wall; (c) applying said self-sealing layer on said bonding layer, said one bonding layer consisting of a composition based on at least one styrenic thermoplastic elastomer A, at least one thermoplastic elastomer B with polyisobutylene block, said thermoplastic elastomer B being different from said thermoplastic elastomer A and at least 140 phr of an extension oil having a number average mass Mn of less than or equal to 5000 g / mol. 45. The method of claim 44, further comprising a step (d) in which the pneumatic object baked is obtained at the end of step (c). 46. The method of claim 44, further comprises an intermediate step (a ’) in which the pneumatic object of step (a) is baked. 47. The method of claim 46, wherein the gas-tight inflation layer has on its surface a film of release agents. 48. The method according to any one of claims 44 to 47, in which the pneumatic object is a pneumatic tire.