Method for treating a plastic film with atmospheric plasma in order to improve the adhesion thereof to an elastomer

Abstract

The invention relates to a method for treating a plastic film, the method comprising a step of depositing, at atmospheric pressure, a thin layer on the film moving at a speed V, the deposition step being carried out by exposure to a cold plasma generated with a power P in a gaseous atmosphere comprising a plasma-forming gas and a volatile precursor of silicon introduced with a mass flow rate D; wherein the precursor is selected from alkoxysilanes and alkoxy-aminosilanes and mixtures thereof; and wherein the ratio R defined by R = [(V x dP) / D] is between 150 000 and 2 800 000 Wm-1.g-1.

Description

[0001] METHOD FOR TREATMENT OF A PLASTIC FILM BY ATMOSPHERIC PLASMA IN ORDER TO IMPROVE ITS ADHESION TO AN ELASTOMER

[0002] technical field

[0003] The present invention falls within the field of plastic films.

[0004] In this context, the present invention proposes a process for treating such plastic films in such a way as to give them excellent adhesion properties to an elastomer or rubber, after their lamination.

[0005] The present invention also proposes a plastic film obtained by said process, an elastomer / plastic film composite and its advantageous use in the medical or pharmaceutical field, in particular as a sealing product or stopper or septum of bottles or as a syringe piston, or in a more general field, as a seal.

[0006] Previous art

[0007] Pharmaceutical products, particularly liquids, including vaccines, are generally transported and stored in containers (vials, bottles, bags, etc.) sealed with a rubber stopper. This stopper often acts as a septum, allowing the product to be pierced with a needle, one or more times (multidose administration), when administered to a patient. These stoppers must, of course, meet the strict and standardized requirements of the pharmaceutical industry. Rubbers, also commonly called elastomers, known for manufacturing such stoppers for medical or pharmaceutical use are often of the bromobutyl or fluorobutyl type.

[0008] In general, a medical or pharmaceutical cap must guarantee the safety and efficacy of the product contained within the container by preventing any contamination or degradation of said product. It must therefore offer complete airtightness / integrity of the container closure (ability to protect the product from the external environment), excellent chemical inertness, and maintenance of product stability.

[0009] In addition, it must show good properties of penetrability (force required to penetrate it with a needle), fragmentation (number of rubber fragments released into the container when the needle penetrates, an essential criterion) and self-sealing for multi-purpose stoppers (ability to reseal the seal after several needle penetrations).

[0010] Finally, it must mechanically withstand the very low temperatures required for the storage of certain pharmaceutical products such as vaccines (e.g., RNA vaccines which require storage temperatures of -80°C) and also be compatible with sterilization (autoclave or gamma irradiation).

[0011] To reduce contamination (or "leaching") of compounds / elements from the elastomer into the pharmaceutical product, as well as the adsorption of the product into the elastomer itself, it has been proposed to coat a rubber stopper with an ETFE (ethylene tetrafluoroethylene) film. Indeed, due to its chemical inertness, hydrophobicity, and low surface energy, ETFE acts as a barrier that protects the pharmaceutical product from contamination by minimizing interaction between the drug and the stopper while maintaining the integrity of the container closure. Such a film is known in the prior art, notably under the name FluroTec®, for use in combination with bromobutyl or fluorobutyl stoppers. These stoppers are described as resistant to temperatures as low as -80°C and can therefore be used to seal vials containing a SARS-CoV-2 vaccine.The composite (rubber cap covered with an ETFE film) is obtained by lamination, particularly hot lamination.

[0012] However, the adhesion of such an ETFE film is relatively weak to elastomers in general. For example, the peel strength of an ETFE film laminated to a halo-butyl rubber is approximately 4 N / 25 mm, which is unacceptable for meeting the requirements of the pharmaceutical industry. This peel strength is even lower for (i) other types of plastic films, particularly halogenated ones, and / or (ii) other types of elastomers (e.g., EPDM or ethylene propylene diene monomer), which are of interest in other fields.

[0013] Thus, it would be of particular interest to have a plastic film that exhibits excellent adhesion to elastomeric materials in general, especially after lamination / pressing, and that, once applied to this material (in the form of caps or syringe plungers), guarantees / maintains the stringent requirements of the pharmaceutical industry (chemical inertness, absence of contamination, sealing, resistance to low temperatures, compatibility with sterilization, etc.). Objectives of the invention

[0014] One objective of the present invention is to overcome the drawbacks of the prior art, in particular those described above.

[0015] In particular, an objective of the present invention is to provide a method for treating a plastic film in order to give it excellent adhesion to an elastomeric material.

[0016] Another objective of the present invention is to provide a method for treating a plastic film in order to give it excellent adhesion to an elastomeric material which is stable over time.

[0017] Another objective of the present invention is to provide a process for treating a plastic film which retains the other intrinsic properties (chemical, physical) of said elastomeric material.

[0018] Another objective of the present invention is to provide a process for treating a plastic film which guarantees / maintains the strict requirements required by the pharmaceutical industry when laminated onto an elastomeric material, for example, a stopper or syringe plunger.

[0019] Finally, yet another objective of the present invention is to provide a process for processing a plastic film that is fast and economically advantageous.

[0020] Description of the invention

[0021] To achieve the aforementioned objectives, the invention provides a method for treating a plastic film having a first surface and a second surface. This method comprises a step of depositing a thin layer onto the first surface of the film, which is moving at a speed V, in an atmospheric pressure chamber. The deposition is carried out by exposing the first surface to a cold plasma in a gaseous atmosphere comprising a plasma-generating gas and at least one volatile silicon precursor. The plasma is generated with a power density dP, and the at least one volatile silicon precursor is introduced into the chamber during the deposition step with a mass flow rate D. The method in which the at least one volatile silicon precursor is selected from alkoxysilanes and alkoxy-aminosilanes and mixtures thereof, and the ratio R defined by R = [(V x dP) / D] is between 150,000 and 2,800,000 W / (nT) 1 .g -1 .

[0022] The invention is thus based on a novel and inventive approach. Indeed, the inventors have found, surprisingly, that the combination of specific parameters of the plasma process of the invention, more precisely (i) a particular precursor and (ii) adherence to a specific relationship between film speed, plasma power density, and precursor flow rate, makes it possible to achieve the aforementioned objectives. Thus, in particular, by following the process of the invention, a plastic film is obtained whose adhesion properties to an elastomer are greatly improved and stable over time, while preserving the other intrinsic (chemical, physical) properties of the elastomer itself.

[0023] The inventors discovered that the process of the invention makes it possible to increase the adhesion of plastic films in general to many types of elastomers. The process of the invention can therefore be used to manufacture useful plastic films in combination with an elastomer, for numerous applications.

[0024] For example, it can be used very advantageously to manufacture a film, for example of ETFE, which then shows significantly increased adhesion to an elastomer (for example, a halo-butyl) after lamination, and which, once covering this material (in the form of caps or syringe pistons), guarantees / maintains the strict requirements required by the pharmaceutical industry (chemical inertness, absence of contamination, sealing, resistance to low temperatures, compatibility with sterilization, etc.).

[0025] As another example, the process of the invention also advantageously allows for the treatment of a PEEK film (the common acronym for poly(ether-ether-ketone)) which can then be combined, by lamination, with excellent adhesion, to an EPDM (ethylene-propylene-diene monomer) type elastomer. EPDM is a standard rubber commonly used for seals but has poor chemical resistance to oils, gasoline, and hydrocarbons. The resulting composite possesses the advantages of this standard rubber (for example, in terms of cost) but exhibits excellent chemical resistance on its surface due to its PEEK film coating. It can therefore be of great interest in the automotive sector (and related fields), particularly as a replacement for Viton®, a material commonly used until now but which automakers are increasingly seeking to limit or even eliminate.Indeed, this material falls into the class of chemicals called "PFAS" (or per- and polyfluoroalkyl substances) which are harmful because of their persistence in the environment due to the strength of the carbon-fluorine bonds they contain and have deleterious effects on humans.

[0026] The invention also relates to a plastic film, which can be obtained by the process of the invention. The invention also relates to a process for manufacturing a composite, comprising a step of laminating, in particular hot laminating, an elastomer with a plastic film according to the invention or obtained by the process according to the invention.

[0027] The invention also relates to a composite consisting of an elastomer covered at least partially with a plastic film according to the invention or obtained by the process according to the invention, showing a peel force of said film on said elastomer greater than 20 N / 25mm.

[0028] Finally, the invention also relates to the use of a plastic film according to the invention or obtained by the process according to the invention, or of a composite according to the invention:

[0029] in the medical or pharmaceutical field, particularly as a sealing product or stopper or syringe plunger; or in a seal, particularly of the toric type.

[0030] Other features, details and advantages of the invention will become apparent from the description below.

[0031] In this description and these claims, it is understood that the terms "a," "an," or "the" mean "at least one" and are not to be limited to "only one," unless explicitly stated otherwise. Furthermore, when a range of values ​​is indicated, the endpoints are included. Finally, all integral and subdomain values ​​within a numeric range are expressly included as if explicitly stated.

[0032] For the sake of clarity, the speed V according to the invention is expressed in m.imim 1 (m / min or meters per minute), the power density dP is expressed in W.mr 2 (or W / m 2 or watts per square meter), and the mass flow rate D is expressed in g.imim 1 (or g / min or grams per minute).

[0033] The plastic film according to the invention has a first surface and a second surface, the first surface being the one treated according to the process of the invention by plasma exposure. The plastic film according to the invention can have variable dimensions, those commonly considered in the intended application and, in particular, those accessible to the device used to implement the process. In particular, the process of the invention makes it possible to treat a film with a large width, for example, 2 meters or even more. Furthermore, the plastic film of the invention can have a thickness of a few microns and up to a few millimeters, for example, from 4 microns to 2 mm. The plastic film of the invention can be made of any plastic suitable for combination, by lamination, with an elastomer-type material, and in particular, any plastic exhibiting unsatisfactory adhesion to said material.The plastic film can therefore be made of a material chosen from the group consisting of halogenated polymers, polyolefins, polyesters, polysulfone type polymers, polyimide (PI) type polymers and their derivatives.

[0034] According to an advantageous embodiment of the invention, the plastic film is made of a halogenated polymer, in particular fluorinated or chlorinated. Preferably, the plastic film is made of a fluorinated polymer. According to this embodiment, preferably and particularly for medical or pharmaceutical applications, the plastic film is made of ETFE (ethylene tetrafluoroethylene), PTFE (propylene tetrafluoroethylene), FEP (fluoroethylene propylene), or PVDF (polyvinylidene fluoride).

[0035] According to another advantageous embodiment of the invention, the plastic film is made of a polyaryletherketone (PAEK) type polymer. Preferably, in this embodiment, the plastic film is made of PEEK.

[0036] According to yet another advantageous embodiment of the invention, the plastic film is made of a polysulfone type polymer, for example, PPSU (polyphenylsulfone).

[0037] According to yet another advantageous embodiment of the invention, the plastic film is made of a polyester, for example, PET (polyethylene terephthalate).

[0038] The film treated / obtained according to the process of the invention advantageously exhibits improved adhesion to an elastomer of interest after being laminated onto said elastomer. In particular, the plastic film demonstrates a significantly increased peel strength compared to that of the initial plastic film (before the treatment according to the invention). For example, after being laminated / pressed onto an elastomer, especially under heat, said film exhibits a peel strength on said elastomer exceeding 20 N / 25 mm, preferably exceeding 30 N / 25 mm, or even exceeding 40 N / 25 mm. It is understood that the lamination is performed with the first surface (the one treated according to the invention) in contact with the elastomer. The peel strength of the film obtained according to the process of the invention is measured by peeling said hot-laminated film onto said raw (unvulcanized) elastomer, said peeling being carried out on a 25 mm wide strip at an angle of 80° and a speed of 300 mm / min.In particular, the film can be hot-laminated onto the elastomer under a pressure of 5.6 MPa. The temperature and duration of the lamination / pressing are adapted to the nature of the elastomer, typically ranging from 60°C to 180°C. After lamination, the sample is cut into a 25 mm wide strip.

[0039] According to the invention, the process includes a step of depositing, in an atmospheric pressure chamber, a thin layer on the first surface of the film.

[0040] The expression "at atmospheric pressure" according to the invention relates to the related field, in particular the field of plasma treatment / deposition, and is perfectly understood by those skilled in the art. Specifically, it also includes a pressure close to atmospheric pressure, that is, a pressure that deviates from atmospheric pressure by a pressure difference (positive or negative) not exceeding a few tens or one or two hundred Pa. More precisely, the pressure deviates from atmospheric pressure by no more than ±100 Pa.

[0041] In this description and claims, the term "thin film" refers to the related field, in particular the field of plasma processing / deposition, and is fully understood by a person skilled in the art.

[0042] According to the invention, the thin film deposition step is performed on the first surface of the film, which is moving within the chamber at a defined speed V. Advantageously, the film speed V during the deposition step is greater than 20, 30, 40, or 50 m / min, preferably greater than 60 m / min, or even greater than 80 m / min. Also advantageously, the film speed V during the deposition step is less than 200 m / min, preferably less than 150 m / min, or even less than 120 m / min.

[0043] According to the invention, in the enclosure, the deposition of the thin film is carried out by exposing the first surface of the film to a cold plasma, generated with a power density dP, in a gaseous atmosphere comprising a plasma-generating gas and at least one volatile silicon precursor.

[0044] By "cold plasma" according to the invention, we mean the definition commonly accepted in the field and clearly understood by a person skilled in the art (and as opposed to "hot" or "thermal" plasma, which has very high temperatures, up to several thousand degrees Celsius, and is used for example to cut or weld metal parts).

[0045] According to a preferred embodiment of the invention, the cold plasma according to the invention is formed by dielectric barrier discharge (DBD), a technique known as such for generating a plasma from a plasma-generating gas. Advantageously, in this embodiment, the spacing between the active surface of the electrodes used to produce the dielectric barrier discharge and the moving film can be adjusted, in particular to ensure the stability and homogeneity of the plasma. By way of example, the distance between the film and the active surface of the electrodes can be adjusted between 1 and 2 mm.

[0046] Typically, the electrodes are connected to a low-frequency (typically one to a few hundred kHz) HV generator with variable power (in W / m²). 2 the unit of surface area referring to the cumulative surface area of ​​the electrodes).

[0047] According to the invention and in a manner known in the field, the power density dP (expressed in Wm 2 ) corresponds to the total electrical power dissipated by the plasma generator in the discharge per unit area of ​​the cumulative electrodes. For example, the power density dP is between 10,000 and 41,000 Wm² 2 .

[0048] According to a particular embodiment of the invention, the exposure is carried out at a temperature below 100°C, in particular by maintaining the enclosure and / or the film within the enclosure at a temperature below 100°C.

[0049] According to the invention, during the deposition step, said at least one volatile silicon precursor is introduced into the chamber with a mass flow rate D. For example, said at least one volatile silicon precursor is introduced into the chamber with a mass flow rate between 0.25 and 2 g / min, or between 0.25 and 1.5 g / min, or even between 0.25 and 1.25 g / min.

[0050] According to the invention and in a manner known in the field, said at least one volatile silicon precursor is introduced into the chamber in gaseous form. Also according to the invention and in a manner known in the field, said at least one volatile silicon precursor is introduced into the chamber in gaseous form in the presence of a carrier gas, typically nitrogen.

[0051] According to the invention, the gaseous atmosphere in the enclosure comprises a plasma-forming gas and at least one volatile silicon precursor.

[0052] Advantageously, the plasma-forming gas is chosen from the group consisting of noble gases, nitrogen, and mixtures thereof. Preferably, the plasma-forming gas is chosen from the group consisting of argon, nitrogen, and mixtures thereof. Nitrogen is particularly preferred. Also preferably, the gaseous atmosphere may include at least one other gas chosen from the group consisting of N₂O, O₂, CO₂, H₂, ethylene, air, and mixtures thereof.

[0053] According to the invention, said at least one volatile silicon precursor is selected from alkoxysilanes, alkoxyaminosilanes, and mixtures thereof. "Alkoxysilane" is understood to mean a silane possessing four alkoxy groups, -OR. "Alkoxyaminosilane" is understood to mean a bifunctional silane possessing one amine group, in particular the primary amine -R-NH2, and three alkoxy groups, -OR.

[0054] Preferably, said at least one volatile silicon precursor is chosen from alkoxy-aminosilanes, in particular alkoxy-aminosilanes of formula Si(O(CH2)xCH3)3((CH2)yNH2) with x= 1; 2; 3 or 4 and y = 1; 2; 3; 4 or 5. Most preferably, said at least one volatile silicon precursor is (3-aminopropyl)triethoxysilane (also known by the acronym APTES) or (3-aminopropyl)trimethoxysilane (also known by the acronym APT MS).

[0055] According to a particular embodiment, the gaseous atmosphere comprises more than one volatile silicon precursor, for example two or even three volatile silicon precursors, potentially all chosen from alkoxysilanes, alkoxy-aminosilanes and mixtures thereof.

[0056] According to the invention, the ratio R is defined by the formula R = [(V x P) / D] and is between 150,000 and 2,800,000 W. dg- 1(where "x" corresponds to a multiplier). Preferably, the ratio R is less than or equal to 2400000 Wm-'.g- 1 , preferably less than or equal to 2,000,000 W.m' 1 .g- 1 or better, less than or equal to 1,600,000 W.m' 1 .g- 1 .

[0057] According to one embodiment of the invention, the thin film deposited in the deposition step comprises at least the following elements: silicon, carbon, and oxygen. In particular, it may be composed of a SiCxOy type composition. Especially when said at least one volatile silicon precursor is selected from alkoxyaminosilanes, the thin film deposited in the deposition step comprises nitrogen, and is, in particular, composed of a SiCxOyNz type composition.

[0058] According to another embodiment of the invention, the thin film deposited in the deposition step has a thickness of less than 10 nm, preferably less than 8 nm, or even less than 5 nm.

[0059] The process of the invention may include one or more other steps before, during, and / or after the deposition step according to the invention. For example, it may be a film activation step before deposition or an extraction step during deposition to extract / remove the gas(s) present in the chamber and / or any by-products created in the plasma and not utilized on the film.

[0060] The present invention also relates to a plastic film obtainable by the process of the invention, particularly supplied in rolls. This plastic film is particularly advantageous because, in addition to the intrinsic properties of the plastic from which it is made, it exhibits increased adhesion to elastomeric materials in general. In particular, said plastic film of the invention has a large width, for example, 2 meters or more. Furthermore, said plastic film can have a thickness of a few microns and up to a few millimeters, for example, from 4 microns to 2 mm.

[0061] The invention relates to a method for manufacturing a composite, comprising a lamination step, particularly a hot lamination step, of an elastomer with a plastic film according to the invention or obtained by the method of the invention. According to this method, preferably, the elastomer is raw (unvulcanized) and the lamination step is carried out hot, for example at a temperature of around 120°C, and comprises vulcanization of said elastomer and pressing.

[0062] Advantageously, for medical or pharmaceutical applications, the elastomer is a halo-butyl and the plastic film is made of ETRE. In this case, the film shows excellent adhesion to the halo-butyl and, once covering this elastomer (in the form of stoppers or syringe pistons for example), guarantees / maintains the strict requirements required by the pharmaceutical industry (chemical inertness, absence of contamination, sealing, resistance to low temperatures, compatibility with sterilization, etc.).

[0063] Advantageously, for more general applications, particularly for seals in the automotive sector or for pumps, the elastomer is EPDM and the plastic film is PEEK. In this case, the film exhibits excellent adhesion to the EPDM and, once covering this elastomer (in the form of an O-ring, for example), guarantees good chemical resistance to oils, gasoline, and hydrocarbons, while retaining the advantages of EPDM (notably its low cost) and avoiding the use of a PFAS-classified material (such as Viton®, commonly used for chemically resistant seals).

[0064] The invention also relates to a composite consisting of an elastomer covered at least partially with a plastic film according to the invention or obtained by the process of the invention, showing a peel force of said film on said elastomer greater than 30 N / 25mm, preferably greater than 40 N / 25mm.

[0065] Finally, the invention also relates to the use of a plastic film according to the invention or obtained by the process according to the invention, or of a composite according to the invention: in the medical or pharmaceutical field, particularly as a sealing product or syringe stopper or plunger; or

[0066] in a seal (for example of the O-ring type), particularly usable in the automotive field or for any other suitable application (for example, in a pump).

[0067] It is understood that the present invention is in no way limited to the embodiments described above and that modifications may be made to them without departing from the scope of the claims. It is further understood that the invention also encompasses all possible combinations of features and preferred features described herein and cited in the claims.

[0068] Furthermore, the following examples are provided for illustrative purposes only and are not intended to limit the scope of the present invention.

[0069] Examples

[0070] Example 1:

[0071] A plastic film made of ETRE (0.1 mm thick) was treated according to the process of the invention, using a roll-to-roll system (600 mm wide roll) and a DBD-type plasma chamber, using the APTES silicon precursor and varying the R-ratio to obtain examples according to the invention (within the claimed range of values) and comparative examples. The spacing between the film and the active surface of the electrodes was set at approximately 1 mm. The conditions used are summarized in Table 1 below.

[0072] Table 1

[0073]

[0074]

[0075] *Total electrode surface area: 0.126 m²2

[0076] For each R value, the film obtained after treatment was evaluated for its adhesion to a bromobutyl elastomer. To this end, a piece of raw bromobutyl was placed between two samples of the treated film, and the assembly was pressed for 6 minutes at 5.6 MPa between two blocks heated to 80°C. Subsequently, the peel strength of the resulting assembly, cut into a 25 mm wide strip, was determined using an AR1000 device (Cheminstrument) during peeling at a 180° angle and a speed of 300 mm / min (the device's force sensor can measure forces up to 50 N). The value of the untreated film was also evaluated and was 3.7 N / 25 mm.

[0077] The peel force results are shown in Fig. 1. It clearly shows that the examples according to the invention exhibit a significantly increased peel force (peel forces all greater than 28 N / 25mm and even close to 50 N / 25 mm for some films) compared to the film before treatment and compared to the comparative examples (peel forces between 10 and 18 N / 25 mm).

[0078] Furthermore, some films according to the invention were analyzed by X-ray induced photoelectron spectroscopy (XPS) on the treated surface side. The atomic percentages of the elements F, O, N, C, and Si were determined from flyover spectra using a Nova-Kratos™ instrument with a monochromatic Al-Ka source (225 W) over an area of ​​300 m x 700 m in normal detection (detection angle θ = 0°). The results show that the surface of the film treated according to the invention (analysis depth < 10 nm) contains the elements C, Si, N, O, and F in significant quantities. The detection of a significant fluorine signal from the plastic film indicates that the deposited layer is thin, specifically less than the analysis depth (10 nm). An estimate based on the analysis of the fluorine signal attenuation indicates a layer thickness between 1 and 6 nm.

[0079] Example 2:

[0080] We carried out a treatment of different types of plastic films according to the process of the invention, using a "roll-to-roll" installation (roll with a width of 600 mm) and a plasma chamber of the DBD type, using the silicon precursor APTES and the conditions 1 to 7 given in example 1 in Table 1. The spacing between the film and the active surface of the electrodes was set at about 1 mm.

[0081] The plastic films used in this example are listed in Table 2, with their reference and thickness.

[0082] Table 2

[0083]

[0084] Each film obtained after treatment was evaluated for its adhesion to a bromo-butyl elastomer. For this purpose, a piece of raw bromo-butyl was placed between two samples of the treated film, and the assembly was pressed for 6 minutes at 5.6 MPa between two blocks heated to 80°C. Subsequently, the peel strength of the resulting assembly, cut into a 25 mm wide strip, was determined using an AR1000 device (Cheminstrument) during peeling at a 180° angle and a speed of 300 mm / min.

[0085] The results obtained are presented in Table 3 below for the different plastic films used in this example. The "NT" values ​​correspond to the untreated film. Conditions 1 to 7 are identical to those described in Example 1 (Table 1). Table 3

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[0089]

[0090]

Claims

DEMANDS 1. A process for treating a plastic film having a first surface and a second surface, said process comprising a step of deposition, in an atmospheric pressure chamber, of a thin layer on said first surface of the film moving at a speed V, said deposition being carried out by exposing said first surface to a cold plasma in a gaseous atmosphere comprising a plasma-generating gas and at least one volatile silicon precursor, the plasma being generated with a power density dP and said at least one volatile silicon precursor being introduced into the chamber during the deposition step with a mass flow rate D; characterized in that said at least one volatile silicon precursor is selected from alkoxysilanes and alkoxy-aminosilanes and mixtures thereof; and in that the ratio R defined by R = [(V x dP) / D] is between 150000 and 2800000 Wm-'.g-'.

2. A method according to the preceding claim, characterized in that the ratio R is less than or equal to 2400000 Wm-'.g-', preferably less than or equal to 2000000 Wm-'.g-'.

3. A method according to any one of the preceding claims, characterized in that the plastic film is made of a halogenated polymer, preferably fluorinated.

4. A process according to any one of the preceding claims, characterized in that said at least one volatile silicon precursor is selected from alkoxy-aminosilanes of formula Si(O(CH2)xCH3)3((CH2) y NH2) with x = 1; 2; 3 or 4 and y = 1; 2; 3; 4 or 5.

5. A process according to the preceding claim, characterized in that said at least one volatile silicon precursor is (3-aminopropyl)triethoxysilane.

6. A method according to any one of the preceding claims, characterized in that the film speed V is greater than 50 m / min, preferably greater than 80 m / min.

7. A process according to any one of the preceding claims, characterized in that said plasma-generating gas is selected from the group consisting of noble gases, nitrogen and mixtures thereof.

8. Plastic film, obtainable by the process according to any one of claims 1 to 7, in particular supplied in rolls.

9. Process for manufacturing a composite, comprising a step of rolling, in particular hot rolling, an elastomer with a plastic film according to claim 8 or obtained by the process according to any one of claims 1 to 7.

10. Composite consisting of an elastomer covered at least partially with a plastic film according to claim 8 or obtained by the process according to any one of claims 1 to 7, showing a peel force of said film on said elastomer greater than 30 N / 25mm, preferably greater than 40 N / 25mm, measured by peeling said hot-laminated film on said raw elastomer, said peeling being carried out on a 25 mm wide strip at an angle of 80° and a speed of 300 mm / min.

11. Use of a plastic film according to claim 8 or obtained by the process according to any one of claims 1 to 7 or of a composite according to claim 10, in the medical or pharmaceutical field, in particular as a sealing product or stopper or syringe plunger.

12. Use according to the preceding claim, characterized in that said plastic film is made of ETRE or PTFE or FEP or PVDF.

13. Use of a plastic film according to claim 8 or obtained by the process according to any one of claims 1 to 7 or of a composite according to claim 10, in a seal, in particular of the toroidal type.

14. Use according to the preceding claim, characterized in that said plastic film is made of a PAEK type polymer, and preferably of PEEK.

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