Film forming composition for preparing monolayer improved in adhesion strength to metalized surface

Abstract

To provide a composition containing a fluoropolymer, which demonstrates a good compromise between final layer dry thickness, drying time, preparation time at room temperature, and the possibility of one-step coating, is easy to prepare, environmentally friendly for the operator, and, while being electrically active, has very high adhesion strength to metal surfaces, as well as a single layer obtained from the composition that exhibits electrical activity.SOLUTION: The present invention relates to a composition comprising a fluoropolymer, a silicon-sulfur compound, a vinyl polymer composed of carbon and hydrogen atoms and optionally, depending on the case, oxygen and / or nitrogen atoms, and a solvent or a mixture of solvents, as well as a method for producing the composition and a method for producing a substrate coated by applying the composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to compositions containing specific combinations of ingredients for preparing monolayers that exhibit improved long-lasting adhesive strength to substrates, particularly metallized substrates. [Background technology]

[0002] Fluoropolymers, such as materials containing polyvinylidene fluoride, are known in particular for their excellent durability and their dielectric and / or piezoelectric properties. They are used in a wide range of applications, especially in electronic applications. In many applications, they are used in the form of coating or printing layers, which must exhibit good adhesive properties.

[0003] However, fluoropolymers have very poor adhesion strength to metals, which is detrimental to their use in electronic applications where a metal surface may be required as a substrate.

[0004] To overcome this problem, several solutions have been developed. One method for promoting the adhesion of fluoropolymers to metal substrates is to add a sulfur-containing adhesion promoter in combination with the fluoropolymer. For example, European Patent Application Publication No. 3638733 and International Publication No. 1982 / 000606A1 disclose compositions containing a fluoropolymer containing units derived from vinylidene fluoride and trifluoroethylene, and a silane agent, in methyl ethyl ketone. Japanese Patent Application Laid-Open Publication No. 2010-182994 describes an organic piezoelectric material for ultrasonic transducers suitable for high frequency and wide band applications, comprising a layer obtained from a composition containing a fluoropolymer and a material capable of forming a covalent bond with an electrode metal, the material containing a mercapto group as a functional group, in methyl ethyl ketone.

[0005] US Patent Application Publication No. 2020 / 0239724 also describes a composition for producing a passivation layer, comprising a fluorocopolymer and a thiol-based adhesion promoter.

[0006] However, these prior art layers do not adhere well to metal substrates, especially after the layer and substrate assembly is immersed in an aqueous solution, a problem that is significant for end uses in harsh environments, especially for outdoor applications or applications that come into contact with water, such as medical devices.

[0007] As mentioned above, fluoropolymers are often used in the form of a layer applied to a substrate. There are several approaches to coating a polymer onto a substrate: one route involves melt processing the polymer, and another route involves solubilizing the polymer in a solvent to obtain a liquid composition. Unlike melt-processable compositions, liquid compositions have the advantage of being able to be applied at room temperature, enabling global energy savings. In addition, liquid compositions can be used in a wide range of coating methods. Therefore, liquid compositions can be used for printing or patterned coatings. Finally, in molten-state processes such as hot-melt slot-die coating, melt-processable compositions exhibit high viscosity and often require high shear rates. The resulting coating film can lack thickness uniformity and surface coverage when thin coatings are targeted to achieve high dielectric performance.

[0008] In the literature, many solvents tend to be used with fluoropolymers. However, the literature lacks precision, and the solvents used are listed in a wide range of chemicals. Therefore, it is difficult to simply select one solvent. In addition, the preparation of the prior art compositions is not easy, especially because the solvent does not sufficiently solubilize the components. Therefore, existing solutions do not provide an easy-to-operate method for obtaining compositions that are available through open-air operation with standard equipment in a compact industrial plant and are environmentally friendly for workers. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent Application Publication No. 3638733 [Patent Document 2] International Publication No. 1982 / 000606 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010 / 182994 [Patent Document 4] US Patent Application Publication No. 2020 / 0239724 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, there is a need for a composition for forming a layer comprising a fluoropolymer that offers a good compromise between the dry thickness of the final layer, the drying time to obtain the dry layer, the preparation time to produce the composition at room temperature, and the possibility to coat the composition in one step using conventional coating / printing techniques.

[0011] There is a need for compositions comprising fluoropolymers that can be easily prepared through open-air operations using standard equipment in compact industrial plants and / or are environmentally friendly for workers, while obtaining monolayers that exhibit very high adhesive strength to substrates, particularly metal or metallized substrates.

[0012] There is also a need for compositions comprising fluoropolymers that are active yet make it possible to obtain monolayers with very high adhesive strength to substrates, especially metal substrates, especially when the components are used in devices that come into contact with fluids such as water. There is a particular need for monolayers that exhibit electroactive properties, especially electric or electronic or piezoelectric or pyroelectric or dielectric or electrostrictive properties.

[0013] There is also a need for electroactive or passivating monolayers obtainable from such compositions. [Means for solving the problem]

[0014] Therefore, the present invention provides a fluoropolymer; a silicon-sulfur compound, a vinyl polymer consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms, - with a solvent or a mixture of solvents The present invention relates to a composition comprising:

[0015] In fact, the inventors have discovered that in order to achieve very good adhesive strength to a single layer metal substrate that can be obtained from the composition, the fluoropolymer and the silicon-sulfur compound should be combined with a vinyl polymer, in particular to make it resistant to contact with aqueous solutions while maintaining the desired active properties of the fluoropolymer.

[0016] In particular, the present inventors have surprisingly discovered that the addition of silicon-sulfur compounds and vinyl polymers to fluoropolymers makes it possible to maintain electroactive properties. Indeed, certain applications require high levels of dielectric properties, such as a dielectric constant. The use of fluoropolymers makes it possible to reach such performance levels, but it was predicted that the addition of an adhesion promoter would reduce these. In contrast, the present invention uses a non-dielectric adhesion promoter to improve the adhesion of the layer to the substrate while preserving electroactive properties, such as dielectric properties. DETAILED DESCRIPTION OF THE INVENTION

[0017] composition Preferably, the sum of the mass contents of the fluoropolymer, the silicon-sulfur compound and the vinyl polymer relative to the total mass of the composition is between 5% and 30%, preferably between 7% and 30%, preferably between 10% and 28%, preferably between 13% and 25%, more preferably between 14% and 20%.

[0018] Preferably, the composition comprises between 70% and 95% by weight, preferably between 70% and 93% by weight, preferably between 72% and 90% by weight, more preferably between 75% and 87% by weight, and even more preferably between 80% and 86% by weight of solvent relative to the total weight of the composition.

[0019] In particular, the compositions of the present invention exhibit a viscosity between 10 and 20,000 cP, preferably between 100 and 10,000 cP.

[0020] The viscosity of the composition is measured at 23°C by using standard laboratory methods using a cone-plate rheometer.

[0021] Preferably, the composition does not contain any surfactants and / or does not contain any foaming agents.

[0022] In fact, it is possible to achieve the desired properties of both the composition and the monolayer by optimizing several parameters, such as the nature of the solvent or the combined mass content of the fluoropolymer, silicon-sulfur compound, and vinyl polymer. These parameters affect several factors, such as viscosity, drying time, film thickness, adhesive strength, adherence to known coating or printing processes, and overall performance. Generally, a high solids content leads to a thicker coating or a stronger adhesive bond. However, for certain end uses, the film must be thin to achieve the desired properties. This is essential, for example, for producing efficient dielectric films. The film thickness depends on the coating process and also on the solids content, viscosity, and surface energy. In fact, the solids content of a coating composition tends to completely cover the surface as a film. The uniformity of the film applied to the substrate is important for quality (the higher the solids content, the higher the coverage). However, the higher the solids content, the more expensive the composition and the higher the viscosity.

[0023] Fluoropolymer The compositions of the present invention comprise at least one fluoropolymer.

[0024] Fluoropolymers are fluorocarbon-based polymers, that is, they contain several carbon-fluorine bonds.

[0025] Fluoropolymers contain units derived from fluorinated monomers (fluoromonomers), which contain at least one carbon-fluorine bond.

[0026] Such fluoromonomers are preferably selected from: a fluoromonomer of formula (I) C(X1)(X2)=C(X3)(X4) (I) wherein each of X1, X2, X3 and X4 is independently selected from H, Cl, Br, F, I and optionally partially or fully halogenated C1-C6 linear or branched alkyl groups, preferably methyl or ethyl groups, provided that at least one of X1, X2, X3 and X4 contains at least one fluorine atom; perfluoro(alkyl vinyl ethers) of the formula Rx-O-CF=CF2 (Rx is a C1-C8, preferably C1-C4, linear or branched alkyl group), such as perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE); - perfluoro(meth)acrylates of formula Ry-O-(O)C-CF=CF2, where Ry is H or a C1-C8, preferably C1-C4, linear or branched alkyl group; - fluoro(meth)acrylates of the formula Rz-O-(O)C-CH=CH2, where Rz is a C1-C8, preferably C1-C4, linear or branched alkyl group containing at least one, preferably three, fluorine atoms; - C3-C6 perfluorocycloalkenes (tetrafluorocyclopropene, hexafluorocyclobutene, octafluorocyclopentene, decafluorocyclohexene); - Perfluoro(1,3-dioxole); - Perfluoro(2,2-dimethyl-1,3-dioxole) (PDD); fluoromonomers of formula CF2=C(F)O-CF2CF(CF3)-O-CF2CF2-X, where X is CO2H, CH2OH, CO2CH3, SO2F, CH2OPO3H or CH2OCN; - fluoromonomers of formula CF2=C(F)-O-CF2CF2SO2F; Formula R-CH2-O-CF=CF2 (wherein R is H or F(CF2) m and m is 1, 2, or 3; Formula R'-O-CF=CH2, where R' is F(CF2) n - and n is 1, 2, or 3; or - Formula F(CF2) z Fluoromonomers of the formula CH2-O-CF=CF2 (where z is 1, 2, 3, 4, or 5).

[0027] The fluoropolymer preferably comprises units derived from a fluoromonomer of formula (I).

[0028] Preferably, in formula (I), each of X1, X2, X3 and X4 is independently selected from H, F, Cl, I, Br or a methyl group optionally comprising one or more substituents selected from F, Cl, I and Br; more preferably, independently selected from H, F, Cl, Br or a methyl group optionally comprising one or more substituents selected from F, Cl and Br; even more preferably, independently selected from H, F, Cl or a methyl group optionally comprising one or more substituents selected from F and Cl; advantageously, independently selected from H, F and optionally one or more F, provided that at least one of X1, X2, X3 and X4 comprises at least one fluorine atom.

[0029] According to an embodiment, each of X1, X2, X3, and X4 is independently selected from H, F, Cl, I, and Br, preferably independently selected from H, F, Cl, and Br, more preferably independently selected from H, F, and Cl, and even more preferably independently selected from H and F, provided that at least one of X1, X2, X3, and X4 comprises at least one fluorine atom.

[0030] According to another embodiment, only one of X1, X2, X3 and X4 is selected from Cl, I and Br, preferably Cl, and the other X1, X2, X3 and X4 are independently selected from H, F or C1-C3 alkyl, preferably C1-C2 alkyl, more preferably methyl, said alkyl or methyl optionally bearing one or more fluorine substituents, with the proviso that at least one of X1, X2, X3 and X4 contains at least one fluorine atom.

[0031] Examples of fluoromonomers of formula (I) include: vinyl fluoride (fluoroethylene), vinylidene fluoride (VDF), 1,2-difluoroethylene, trifluoroethylene (TrFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), trifluoropropenes such as 3,3,3-trifluoropropene, tetrafluoropropenes such as 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene or 1, Pentafluoropropenes such as 2,3,3,3-pentafluoropropene, hexafluoropropene, hexafluoroisobutylene, 3,3,3-trifluoro-2-(trifluoromethyl)propene, perfluorobutylethylene (PFBE), bromofluoroethylene (1-bromo-1-fluoroethylene or 1-bromo-2-fluoroethylene), bromodifluoroethylene (1-bromo-2,2-difluoroethylene or 1-bromo-1,2-difluoroethylene), bromotrifluoroethylene (cis or trans-1-bromo-3,3,3-trifluoropropene or 2-bromo-3,3,3-trifluoropropene), chlorofluoroethylene (CFE) (1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene), chlorodifluoroethylene (1-chloro-2,2-difluoroethylene or 1-chloro-1,2-difluoroethylene), chlorotrifluoroethylene (CTFE) (cis or trans-1-chloro-3,3,3-trifluoropropene or 2 -chloro-3,3,3-trifluoropropene), bromotrifluoropropene, chlorotrifluoropropene, (1 or 2 or 3 or 4)-bromo-(1 or 2)-fluorobutene, (1 or 2 or 3 or 4)-chloro-(1 or 2)-fluorobutene, (2 or 3 or 4)-chloro-1,1-difluorobutene, (2 or 3 or 4)-bromo-1,1-difluorobutene, (3 or 4)-bromo-1,1,2-trifluorobutene, and (3 or 4)-chloro-1,1,2-trifluorobutene.

[0032] A fluoropolymer may be a homopolymer of a fluoromonomer or may be obtained by copolymerizing a fluoromonomer with one or more other fluoromonomers and / or other monomers that are not fluoromonomers to form a copolymer.

[0033] Copolymer means a polymer derived from several types of monomers. Copolymers according to the invention are in particular copolymers of two monomers (dipolymers) or of three different monomers (terpolymers).

[0034] Preferably, the total molar content of fluoromonomers in the fluoropolymer is 40% to 100%, preferably 50% to 95%, more preferably 60% to 90%, based on the total molar content of monomers in the fluoropolymer.

[0035] Monomers which are not fluoromonomers and which can be copolymerized with fluoromonomers are preferably selected from non-fluorinated ethylenic monomers.

[0036] Ethylenic monomers are molecules containing at least one carbon-carbon double bond. Preferably, non-fluorinated ethylenic monomers are of the formula C(R1)(R2)=C(R3)(R4), where R1, R2, R3, and R4 are independently selected from the group consisting of a hydrogen atom, an aromatic group, preferably phenyl, optionally a C1-C10, preferably C1-C4 linear, branched, or cyclic, saturated or unsaturated hydrocarbon group, possibly further comprising an ether, ester, nitrile, carboxyl, amine, and / or amide group, optionally including the possibility that two groups from R1, R2, R3, and R4 together form a 5-, 6-, or 7-membered ring.

[0037] Advantageously, the non-fluorinated ethylenic monomer is chosen from ethylene, propylene, methyl or ethyl vinyl ether, vinyl esters, allyl glycidyl ether, (meth)acrylic acid, (meth)ethyl(meth)acrylic acid, and vinyl acetate.

[0038] Preferably, the molar content (or molar ratio) of the first fluoromonomer in the fluoropolymer (particularly when the first fluoromonomer is vinylidene fluoride) is 40% to 98%, preferably 50% to 90%, more preferably 60% to 80%, and even more preferably 60% to 70%. Preferably, the molar content of the second fluoromonomer in the fluoropolymer is 2% to 60%, preferably 10% to 50%, more preferably 20% to 40%, and even more preferably 30% to 40%, relative to the total molar content of the monomers in the fluoropolymer.

[0039] According to one embodiment, the fluoropolymer is a dipolymer of two different fluoromonomers, namely a first fluoromonomer and a second fluoromonomer, each independently as described above.

[0040] Preferably, the fluoropolymer is a terpolymer of at least three different fluoromonomers, i.e., a first fluoromonomer, a second fluoromonomer, and a third fluoromonomer, each independently as described above.

[0041] Terpolymers are particularly advantageous since they make it possible to obtain high electroactive properties, in particular high dielectric properties and especially high piezoelectric properties.

[0042] The fluoropolymer may comprise or consist of a first fluoromonomer unit and a second fluoromonomer unit. The fluoropolymer may also comprise or consist of a first fluoromonomer unit, a second fluoromonomer unit and a third fluoromonomer unit.

[0043] In particular, the fluoropolymer is a copolymer of vinylidene fluoride (as the first fluoromonomer) and at least one second fluoromonomer (the second fluoromonomer is a fluoromonomer as described above, with the proviso that it is different from vinylidene fluoride). More preferably, the fluoropolymer is a terpolymer of vinylidene fluoride (as the first fluoromonomer), the second fluoromonomer, and a third fluoromonomer, with the proviso that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0044] The fluoropolymer may comprise vinylidene fluoride units and the second fluoromonomer units (and, if present, the third fluoromonomer units) or may consist of vinylidene fluoride units and the second fluoromonomer units (and, if present, the third fluoromonomer units).

[0045] The second fluoromonomer is preferably a fluoromonomer of formula (I) described above.

[0046] When present, the third fluoromonomer is preferably a fluoromonomer of formula (I) above.

[0047] Preferably, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, F, Cl, I, Br, or a methyl group optionally containing one or more substituents selected from F, Cl, I, and Br, preferably independently selected from H, F, Cl, Br, or a methyl group optionally containing one or more substituents selected from F, Cl, and Br, with the proviso that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0048] More preferably, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, Cl, F, or a methyl group optionally containing one or more F or Cl, preferably H, F, or a methyl group optionally containing one or more F, with the proviso that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0049] According to one embodiment, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, F, Cl, I, or Br, preferably selected from H, F, Cl, or Br, more preferably selected from H, F, and Cl, with the proviso that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0050] According to another embodiment, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein only one of X1, X2, X3 and X4 is selected from Cl, I and Br, preferably Cl and Br, and the other X1, X2, X3 and X4 are independently selected from H, F or C1-C3 alkyl, preferably C1-C2 alkyl, more preferably methyl, said alkyl or methyl optionally carrying one or more fluorine substituents, and advantageously the other X1, X2, X3 and X4 are independently selected from H and F, with the proviso that at least one of X1, X2, X3 and X4 contains at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0051] Preferably, the fluoropolymer is a copolymer of vinylidene fluoride and (at least) vinyl fluoride (fluoroethylene), vinylidene fluoride (VDF), 1,2-difluoroethylene, trifluoroethylene (TrFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), trifluoropropenes such as 3,3,3-trifluoropropene, tetrafluoropropenes such as 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene or 1, Pentafluoropropenes such as 2,3,3,3-pentafluoropropene, hexafluoropropene, hexafluoroisobutylene, 3,3,3-trifluoro-2-(trifluoromethyl)propene, perfluorobutylethylene (PFBE), bromofluoroethylene (1-bromo-1-fluoroethylene or 1-bromo-2-fluoroethylene), bromodifluoroethylene (1-bromo-2,2-difluoroethylene or 1-bromo-1,2-difluoroethylene), bromotrifluoroethylene (cis or trans isomers), 1-bromo-3,3,3-trifluoropropene or 2-bromo-3,3,3-trifluoropropene), chlorofluoroethylene (CFE) (1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene), chlorodifluoroethylene (1-chloro-2,2-difluoroethylene or 1-chloro-1,2-difluoroethylene), chlorotrifluoroethylene (CTFE) (cis or trans 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene), bromo-3,3,3-trifluoropropene, ... It is a copolymer, preferably a dipolymer, with a second fluoromonomer selected from bromotrifluoropropene, chlorotrifluoropropene, (1 or 2 or 3 or 4)-bromo-(1 or 2)-fluorobutene, (1 or 2 or 3 or 4)-chloro-(1 or 2)-fluorobutene, (2 or 3 or 4)-chloro-1,1-difluorobutene, (2 or 3 or 4)-bromo-1,1-difluorobutene, (3 or 4)-bromo-1,1,2-trifluorobutene, and (3 or 4)-chloro-1,1,2-trifluorobutene.

[0052] According to the most preferred embodiment, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and a fluoromonomer selected from (at least) hexafluoropropylene, chlorofluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene and trifluoroethylene, preferably selected from chlorofluoroethylene, chlorotrifluoroethylene and trifluoroethylene.

[0053] According to a preferred embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I), and a third fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, F, Cl, I, Br, or a methyl group optionally containing one or more substituents selected from F, Cl, I, and Br, preferably independently selected from H, F, Cl, Br, or a methyl group optionally containing one or more substituents selected from F, Cl, and Br, with the proviso that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and with the proviso that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0054] More preferably, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I), and a third fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, Cl, F, or a methyl group optionally containing one or more F or Cl, preferably H, F, or a methyl group optionally containing one or more F, provided that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and provided that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0055] According to one embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I), and a third fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, F, Cl, I, or Br, preferably H, F, Cl, or Br, more preferably H, F, and Cl, provided that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and provided that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0056] According to another embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I), and a third fluoromonomer of formula (I), wherein only one of X1, X2, X3, and X4 is selected from Cl, I, and Br, preferably Cl and Br, and the other X1, X2, X3, and X4 are independently selected from H, F, or C1-C3 alkyl, preferably C1-C2 alkyl, more preferably methyl, said alkyl or methyl optionally having one or more fluorine substituents; advantageously, the other X1, X2, X3, and X4 are independently selected from H and F, with the proviso that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and the second and third fluoromonomers are different from vinylidene fluoride and are different from each other.

[0057] Preferably, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer, and a third fluoromonomer, the second and third fluoromonomers being independently selected from vinyl fluoride (fluoroethylene), vinylidene fluoride (VDF), 1,2-difluoroethylene, trifluoroethylene (TrFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), a trifluoropropene such as 3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, or 1,3,3,3-tetrafluoropropene. tetrafluoropropenes such as 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene, pentafluoropropenes such as hexafluoropropene, hexafluoroisobutylene, 3,3,3-trifluoro-2-(trifluoromethyl)propene, perfluorobutylethylene (PFBE), bromofluoroethylene (1-bromo-1-fluoroethylene or 1-bromo-2-fluoroethylene), bromodifluoroethylene (1-bromo-2,2-difluoroethylene or 1-bromo -1,2-difluoroethylene), bromotrifluoroethylene (cis or trans 1-bromo-3,3,3-trifluoropropene or 2-bromo-3,3,3-trifluoropropene), chlorofluoroethylene (CFE) (1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene), chlorodifluoroethylene (1-chloro-2,2-difluoroethylene or 1-chloro-1,2-difluoroethylene), chlorotrifluoroethylene (CTFE) (cis or trans 1-chloro-3,3,3- trifluoropropene or 2-chloro-3,3,3-trifluoropropene), bromotrifluoropropene, chlorotrifluoropropene, (1 or 2 or 3 or 4)-bromo-(1 or 2)-fluorobutene, (1 or 2 or 3 or 4)-chloro-(1 or 2)-fluorobutene, (2 or 3 or 4)-chloro-1,1-difluorobutene, (2 or 3 or 4)-bromo-1,1-difluorobutene, (3 or 4)-bromo-1,1,2-trifluorobutene, (3 or 4)-chloro-1,1,2-trifluorobutene.

[0058] According to a most preferred embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer, and a third fluoromonomer, the second and third fluoromonomers being independently selected from hexafluoropropylene, chlorofluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, and trifluoroethylene, preferably selected from chlorotrifluoroethylene, chlorotrifluoroethylene, and trifluoroethylene.

[0059] Preferably, the terpolymer is a polymer of vinylidene fluoride, trifluoroethylene (as the second fluoromonomer) and chlorotrifluoroethylene (P(VDF-TrFE-CTFE)) (as the third fluoromonomer), or a terpolymer of vinylidene fluoride, trifluoroethylene (as the second fluoromonomer) and chlorofluoroethylene (P(VDF-TrFE-CFE)) (as the third fluoromonomer).

[0060] Preferably, the molar content (or molar ratio) of vinylidene fluoride in the fluoropolymer is 40% to 98%, preferably 50% to 80%, more preferably 60% to 75%, and even more preferably 60% to 70%. Preferably, the molar content of the second fluoromonomer in the fluoropolymer is 15% to 45%, preferably 20% to 40%, and more preferably 25% to 30%, based on the total molar content of the monomers in the fluoropolymer. Preferably, the molar content of the third fluoromonomer in the fluoropolymer is 1% to 15%, preferably 3% to 12%, and more preferably 5% to 10%, based on the total molar content of the monomers in the fluoropolymer.

[0061] The weight average molar mass (weight average molecular weight) Mw of the fluoropolymer is preferably at least 100,000 g.mol -1 , preferably at least 200,000 g.mol -1 , more preferably at least 300,000 g.mol -1 , and even more preferably at least 400,000 g.mol-1 and preferably from 200,000 to 1,000,000 g.mol -1 The molecular weight distribution can be determined by size exclusion chromatography (SEC).

[0062] The composition of the present invention preferably comprises from 3% to 30% by weight, preferably from 5% to 25% by weight, preferably from 7% to 20% by weight, preferably from 8% to 18% by weight of fluoropolymer relative to the total weight of the composition.

[0063] Silicon-sulfur compounds The compositions of the present invention comprise at least one silicon-sulfur compound.

[0064] Silicon-sulfur compounds are compounds containing at least one silicon atom and at least one sulfur atom, preferably at least one silane group and / or at least one silazane group, and at least one sulfur atom, more preferably at least one silane group and at least one sulfur atom.

[0065] The silane group is preferably a group of formula -Si(Ra)(Rb)(Rc), where Ra, Rb, and Rc are each independently selected from H, OH, Alk, and -O-Alk (Alk is a C1-C8 linear or branched alkyl group), preferably OH, Alk, and -O-Alk.

[0066] A silazane group contains at least a Si-N bond, and preferably contains at least one nitrogen atom covalently bonded to one hydrogen atom and two silicon atoms (-Si-NH-Si- group).

[0067] Preferably, Ra, Rb, and Rc are each independently selected from Alk and -O-Alk.

[0068] Preferably, Alk (or independently the Alk of the -O-Alk group) is a C1-C4 linear or branched alkyl group, more preferably a methyl or ethyl group, even more preferably a methyl group.

[0069] Preferably, in the silicon-sulfur compound, the sulfur atom of the thiol functional group is not directly bonded to a silicon atom.

[0070] More preferably, the sulfur atoms of the silicon-sulfur compound are present in the form of -S-(Rd) groups, where (Rd) is selected from the group consisting of H and organic moieties containing 1 to 30 carbon atoms and at least one nitrogen atom and / or at least one oxygen atom. Preferably, (Rd) is selected from the group consisting of H and organic moieties consisting of 1 to 30 carbon atoms, hydrogen atoms, and one or several nitrogen atoms and / or one or several oxygen atoms.

[0071] Preferably, the silicon-sulfur compound has the formula (II): (Rd)S-Rw-Si(Ra)(Rb)(Rc) (II) wherein Rw is a linear or branched or cyclic group containing 1 to 18 carbon atoms and optionally containing one or several oxygen and / or nitrogen atoms, and Ra, Rb, Rc, and Rd are as described above according to any embodiment. More preferably, Rw is a C1-C12, preferably C1-C8, preferably C1-C6, preferably C1-C4, more preferably C2-C4 linear or branched, preferably linear, alkyl or alkylene group, preferably an alkyl group.

[0072] According to a preferred embodiment, Rd is H. According to this embodiment, the silicon-sulfur compound is a mercaptosilane, i.e., a compound comprising at least one silane group and at least one thiol functional group (—SH).

[0073] Preferably, the silicon-sulfur compound is not polymeric.

[0074] Preferably, the silicon-sulfur compound has a concentration of 800 g mol -1 Less than 600 g mol -1 Less than 400 g mol -1 Less than 250 g mol -1 Less than 80 g mol -1 to 800 g·mol -1 The molecular weight is between .

[0075] Non-limiting examples of silicon-sulfur compounds include: - octanthioic acid, S-[3-(triethoxysilyl)propyl] ester, reaction products with 2-methyl, 1,3-propanediol and 3-(triethoxysilyl)-1-propanethiol (EC number: 485-270-1); - 3-(triethoxysilyl)propanethiol (CAS number 14814-09-6); - 3-(dimethoxymethylsilyl)-2-methylpropanethiol (CAS number 14857-92-2); - 3-(methoxydimethylsilyl)propanethiol (CAS number 14857-97-7); - Hexamethylene diisocyanate, oligomers, reaction products with 3-aminopropylmethylamine, trimethylacetaldehyde and 3-trimethoxysilylpropane-1-thiol (CAS number 161278-26-8); - Pentaerythritol, propoxylated, reaction products with 3-isocyanato-3,5,5-trimethylcyclohexyl isocyanate and 3-trimethoxysilylpropane-1-thiol (CAS number 161308-00-5); - hexamethylene diisocyanate, trimer, reaction products with (3-aminopropyl)methylamine, benzaldehyde and 3-trimethoxysilylpropane-1-thiol (CAS number 162491-90-9); - 2-methyl-3-(triethoxysilyl)propanethiol (CAS number 17980-28-8); - 2-(triethoxysilyl)ethanethiol (CAS number 18236-15-2); - (Trimethylsilyl)methyl thiocyanate (CAS number 18293-51-1); - Trimethylsilyl isothiocyanate (CAS number 2290-65-5); - 3-(dimethoxymethylsilyl)propanethiol (CAS number 31001-77-1); - 1-allyl-3-[3-(triethoxysilyl)propyl]thiourea (CAS number 42168-36-5); - 3-trimethoxysilylpropane-1-thiol (CAS number 4420-74-0); - 4-(triethoxysilyl)butane-2-thiol (CAS number 57640-10-5); - 2-[3-(trimethoxysilyl)propyl]isothiouronium chloride (CAS number 58505-58-1); - 3-[tris(2-ethoxyethoxy)silyl]propanethiol (CAS number 67724-41-8); - 2-(trimethoxysilyl)ethanethiol (CAS number 7538-45-6); - A mixture of S-(3-trimethoxysilyl)propyl 19-isocyanato-11-(6-isocyanatohexyl)-10,12-dioxo-2,9,11,13-tetraazanonadecanethioate and S-(3-(trimethoxysilyl)propyl 17-isocyanato-9-(isocyanatohexyl-aminocarbonyl)-10-oxo-2,9,11-triazaheptadecanethioate (CAS number 85702-90-5); - 1,3-dibutyl-2-[3-(triethoxysilyl)propyl]isothiouronium chloride (CAS number 90210-34-7); - 1,3-diphenyl-2-[3-(triethoxysilyl)propyl]isothiourea, monohydrochloride (CAS number 90210-35-8); - 3-[tris(decyloxy)silyl]propanethiol (CAS number 93777-94-7); - 1-methyl-3-(triethoxysilyl)propyl thiocyanate (CAS number 94087-37-3); - 2-methyl-3-(triethoxysilyl)propyl thiocyanate (CAS number 94087-38-4); - 3-[tris(octyloxy)silyl]propanethiol (CAS number 94291-66-4).

[0076] Advantageous examples of silicon-sulfur compounds include: - 3-(triethoxysilyl)propanethiol (CAS number 14814-09-6); - 3-(dimethoxymethylsilyl)-2-methylpropanethiol (CAS number 14857-92-2); - 3-(methoxydimethylsilyl)propanethiol (CAS number 14857-97-7); - 2-methyl-3-(triethoxysilyl)propanethiol (CAS number 17980-28-8); - 2-(triethoxysilyl)ethanethiol (CAS number 18236-15-2); - 3-(dimethoxymethylsilyl)propanethiol (CAS number 31001-77-1); - 3-trimethoxysilylpropane-1-thiol (CAS number 4420-74-0); - 4-(triethoxysilyl)butane-2-thiol (CAS number 57640-10-5); - 3-[tris(2-ethoxyethoxy)silyl]propanethiol (CAS number 67724-41-8); - 2-(trimethoxysilyl)ethanethiol (CAS number 7538-45-6); - 3-[tris(decyloxy)silyl]propanethiol (CAS number 93777-94-7); - 3-[tris(octyloxy)silyl]propanethiol (CAS number 94291-66-4).

[0077] The composition of the present invention preferably comprises from 0.05% to 0.3% by weight, preferably from 0.08% to 0.25% by weight, preferably from 0.1% to 0.2% by weight, preferably from 0.12% to 0.18% by weight of silicon-sulfur compounds relative to the total weight of the composition.

[0078] The composition of the present invention preferably comprises from 0.1% to 5% by weight, preferably from 0.3% to 3% by weight, preferably from 0.5% to 2% by weight, preferably from 0.8% to 1.5% by weight of silicon-sulfur compound relative to the weight of the fluoropolymer.

[0079] vinyl polymer The compositions of the present invention comprise at least one vinyl polymer consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms.

[0080] Vinyl polymers contain units derived from one or several vinyl monomers.

[0081] A vinyl monomer refers to a small organic molecule that contains at least one carbon-carbon double bond.

[0082] Preferably, the vinyl monomer has the following formula: C(X)(X')=C(X'')(X'''), where X, X', X'' and X''' are independently selected from the group consisting of a hydrogen atom, an OH group, a COOH group, a CN group, an aromatic group, preferably a phenyl group, a saturated or unsaturated hydrocarbon group containing 1 to 10 carbon atoms, preferably 2 to 10 carbon atoms, said aromatic group or hydrocarbon group optionally further containing an OH group, an ester group, a carboxyl group, an amine group, a nitrile group and / or an amide group.

[0083] The vinyl monomer is preferably selected from the group consisting of C2 to C8, preferably C2 to C4, alkenyl monomers, C4 to C12 diene monomers, acrylate monomers, styrene monomers, vinyl alcohols, vinyl acetate, acrylamide monomers, maleic acid, and acrylonitrile.

[0084] The vinyl polymer may also be an elastomer such as, but not limited to, a copolymer of acrylonitrile and ethylene, or a terpolymer of ethyl, acrylate and other vinyl monomers.

[0085] The vinyl polymer may also be a PVA copolymer, a copolymer of vinyl acetate and acrylic acid, or a polyacrylamide.

[0086] Preferably, the vinyl polymer is an acrylate polymer.

[0087] An acrylate polymer is a polymer based on (or derived from) acrylic acid or an acrylic acid derivative, and therefore comprises units derived from acrylate monomers.

[0088] An acrylate monomer is a molecule containing at least an ester functional group and an unsaturated C=C double bond directly connected to the carbon of the acid or ester functional group. In other words, an acrylate monomer is a vinyl monomer containing an ester group, i.e., two double-bonded carbon atoms are directly attached to a carbonyl group. Acrylate polymers belong to the family of vinyl polymers.

[0089] According to the present invention, acrylic acid is included in the definition of acrylate monomers.

[0090] Preferably, the acrylate polymer comprises units derived from an acrylate monomer of formula (III): [ka] wherein Xa and Xb are independently selected from H, a -CN group, and a C1-C8 linear, branched, or cyclic, saturated or unsaturated group containing 1 to 8 carbon atoms; and Xc is selected from H, a benzyl group, and a linear, branched, or cyclic, saturated or unsaturated aliphatic or aromatic group containing 1 to 24 carbon atoms, optionally substituted with at least one OH group and / or one COOH group, and / or optionally interrupted by at least one -O- atom.

[0091] Preferably, Xa and Xb are independently selected from H and C1-C8 straight or branched alkyl groups.

[0092] Preferably, Xa=H.

[0093] Preferably, Xb=H, a —CN group, or a C1 to C2 alkyl group, preferably H or a C1 to C2 alkyl group, more preferably H or a methyl group.

[0094] Preferably, Xc is selected from: - saturated, linear or branched alkyl radicals of C1 to C24, preferably C1 to C16, more preferably C1 to C8, even more preferably C1 to C4, advantageously methyl or ethyl, and - an -AO-Rx group, where A is -CH2CH(OH)CH2- or -CH2CH(CH2OH)-, and Rx is a C10 to C22 linear or branched alkyl group.

[0095] More preferably, Xc is a saturated linear or branched alkyl group of C1 to C24, preferably C1 to C16, more preferably C1 to C8, even more preferably C1 to C4, advantageously methyl or ethyl.

[0096] The acrylate monomer may be an acrylate having an additional methyl group attached to Xb and Xc being a methyl group. The acrylate monomer may also be a methacrylate. One of the most common methacrylate polymers is polymethyl methacrylate (PMMA).

[0097] The acrylate monomer is in particular ethyl acrylate, ethyl methacrylate, butyl acrylate, ethylhexyl acrylate or a derivative.

[0098] The acrylate polymer may be a homopolymer of an acrylate monomer, preferably of formula (III), or may be obtained by copolymerizing an acrylate monomer with one or more other acrylate monomers and / or other monomers that are not acrylate monomers to form a copolymer.

[0099] For example, the acrylate polymer may be a copolymer of methyl acrylate and methyl methacrylate, a copolymer of ethyl acrylate and methyl acrylate, or a copolymer of butyl acrylate and 2-ethylhexyl acrylate.

[0100] The acrylate polymer may also be an acrylonitrile-styrene-(meth)acrylate terpolymer, a styrene-acrylonitrile copolymer with a grafted acrylic elastomer, or a copolymer of styrene and an acrylate monomer. The monomer that is not an acrylate monomer and can be copolymerized with the acrylate monomer is preferably selected from the vinyl monomers mentioned above, with the proviso that the vinyl monomer is not an acrylate monomer.

[0101] Monomers that are not acrylate monomers and can be copolymerized with acrylate monomers may be C2 to C8, preferably C2 to C4, alkenyl monomers, C4 to C12 diene monomers, styrene monomers, vinyl alcohols, vinyl acetate, acrylamide monomers, maleic acid, and acrylonitrile.

[0102] The acrylic monomer may be ethyl acrylate, butyl acrylate, ethylhexyl acrylate or a derivative.

[0103] The vinyl (co)monomer is preferably of formula C(X)(X')=C(X'')(X'''), where X, X', X'' and X'''' are as defined above.

[0104] Preferably, X=X'=H.

[0105] According to an embodiment, X=X'=H, X" is H or a C1-C2 alkyl group, preferably H, and X"' is -C6H5, -CN, -C(O)NH2, -NC4H6O, -C(O)NHC(CH3), -C(O)N(CH3), C(O)NHC(CH3)2(CH2)4CH3, and -C(O)NHC(CH3)2CH2S(O)(O)OH.

[0106] According to another embodiment, X=X'=H, X"=H or a C1-C2 alkyl group, preferably H, and X"' is -OC(O)-Xm, where Xm is a linear or branched C1-C18 alkyl group.

[0107] Preferably, the vinyl polymer is non-fluorinated, which means a vinyl polymer that does not contain any fluorine atoms.

[0108] According to an embodiment, the vinyl polymer is not sodium poly(meth)acrylate. In particular, the vinyl polymer is not a superabsorbent polymer. In particular, the vinyl monomer is not an alkali salt of acrylic acid or an acrylate monomer.

[0109] The composition of the present invention preferably comprises 0.05% to 0.3% by mass, preferably 0.08% to 0.25% by mass, preferably 0.1% to 0.2% by mass, preferably 0.12% to 0.18% by mass of vinyl polymer relative to the total mass of the composition.

[0110] The composition of the present invention preferably comprises 0.1% to 5% by weight, preferably 0.3% to 3% by weight, preferably 0.5% to 2% by weight, preferably 0.8% to 1.5% by weight of vinyl polymer relative to the weight of the fluoropolymer.

[0111] solvent The composition of the present invention comprises at least one solvent. The composition may comprise a blend of at least two solvents. The ratio between the solvents can be determined depending on their respective miscibility, boiling point, and toxicity characteristics. The solvent blend can be adapted depending on the target thickness of the wet and / or dry monolayer comprising the composition. The solvent blend can also be adapted in accordance with industry standards for environmentally friendly areas.

[0112] In the case of a blend of at least two solvents, each solvent is preferably as described below.

[0113] Preferably, the solvent has a boiling point at atmospheric pressure between 95°C and 180°C, preferably between 100°C and 150°C.

[0114] Indeed, it is preferable to use a solvent whose boiling point is not too high in order to minimize the energy required to dry the composition after it has been coated on the substrate, whereas a boiling point that is too low can pose safety issues (e.g., high flammability).

[0115] Preferably, the solvent is an oxyhydrocarbonated solvent, preferably containing between 3 and 7, more preferably between 4 and 6, carbon atoms, and preferably containing at least one ester or ketone functional group, advantageously selected from the group consisting of cyclopentanone, propyl acetate, and propylene glycol methyl ether acetate.

[0116] Oxyhydrocarbonated solvents are solvents that consist of carbon, hydrogen, and oxygen atoms.

[0117] Such solvents represent a good compromise between the ability to easily solubilize (in a short time and at room temperature) fluoropolymers, silicon-sulfur compounds, and vinyl polymers with a total mass content between 12% and 30%, while obtaining a composition with the right viscosity to be coated on a substrate and with good stability (flammability and toxicity).

[0118] The present invention also relates to a method for preparing the composition of the present invention, comprising the step of mixing a fluoropolymer, a silicon-sulfur compound, and a vinyl polymer in a solvent.

[0119] The method preferably comprises a first step of preparing a fluoropolymer solution by mixing a fluoropolymer and a solvent, followed by a step of adding a silicon-sulfur compound and a vinyl polymer into the fluoropolymer solution.

[0120] Preferably, all mixing steps are carried out at a temperature between 15°C and 30°C.

[0121] The present invention also relates to a method for preparing a coated substrate, which comprises applying a composition according to the present invention to the surface or part of the surface of a substrate, followed by evaporating the solvent.

[0122] The substrate may be, in particular, glass, silicon, quartz, a polymeric material, a metal, or a mixed surface made up of several of these materials.

[0123] Preferably, the substrate is or comprises a metal, the metal being selected in particular from gold, stainless steel, copper and aluminium, chromium and silver.

[0124] Preferably, the substrate comprises a metal surface, in particular a gold, stainless steel, copper, and aluminum, chromium, or silver surface, more particularly a copper or gold surface. Preferably, the monolayer is applied to and in contact with said metal surface.

[0125] According to one embodiment, the substrate comprises a gold surface, preferably consisting solely of gold.

[0126] According to another embodiment, the substrate comprises a copper surface, preferably consisting solely of copper.

[0127] The substrate may be of any shape: it may be flat or contoured, smooth or rough, linear or curved, porous or non-porous. [Brief explanation of the drawings]

[0128] [Figure 1] Figure 1 is a schematic diagram of the circuit used to measure the capacitance and dissipation factor of a polymer monolayer.

[0129] The following examples illustrate the present invention without, however, limiting it. [Example]

[0130] Example 1 - Effect of the presence of compounds and the properties of the compounds On a laboratory scale, several compositions were prepared according to the following protocol (each step is carried out at room temperature): 1 / Weigh out the solvent into a vial. 2 / The fluoropolymer is weighed into the same vial and the mixture is stirred for 30 minutes and then allowed to stand for 1 hour. 3 / The silicon-sulfur compound and the vinyl polymer are weighed and introduced into a vial. The mixture is then stirred for 10 minutes and then left to stand until all air bubbles have disappeared. The total content of "active ingredients" (fluoropolymer, silicon-sulfur compound, and vinyl polymer) is 15% by weight.

[0131] Each composition is then applied by screen printing onto a metallized substrate and the solvent is evaporated by heating.

[0132] The adhesion of each layer was evaluated using cellophane tape according to the following protocol: Tape type: 3M2525 Adhesion strength to steel: 75N / 100mm Process: 1 / Cut a piece of adhesive tape approximately 3cm long and fold one end over. 2 / Apply adhesive tape to the sample by applying controlled and even pressure (finger pressure) to its surface. 3 / Using moderate, consistent force (by hand), peel the adhesive tape 180°. 4 / Visually inspect the test area on the sample to identify any delamination of the film on the substrate. Scoring criteria: 5: No delamination, all layers are still intact on the substrate 4: Less than 5% of the layers (surface) were delaminated over the area where the tape was applied 3: Between 5% and 15% of the layers (surface area) were delaminated over the area where the tape was applied. 2: Between 15% and 35% of the layers (surface) were delaminated over the area where the tape was applied. 1: Between 35% and 65% of the layers (surface area) were delaminated over the area where the tape was applied 0: More than 65% of the layers (on the surface) were delaminated over the area where the tape was applied

[0133] Measurement of the adhesive strength level of each monolayer after immersion in aqueous solution was also performed according to the following protocol: Immersion delay: 3 days, 7 days, 10 days, 14 days Process: 1 / Prepare a tank of aqueous solution. 2 / Immerse each sample completely in the aqueous solution, carefully avoiding contact or rubbing against the layer (which could cause damage). 3 / Close the container to prevent evaporation of the solution. 4 / Remove the sample after x days of immersion. 5 / Carefully dab with a lint-free cloth to remove any remaining aqueous solution from the layer, ensuring the layer is preserved and allowed to dry. 6 / Carry out a peel test using the procedures and criteria specified above.

[0134] The details of the composition of each layer and the results of the tests carried out on each layer are summarized in Table 1 (the vinyl polymer content and adhesion promoter content are calculated relative to the mass of the fluoropolymer):

[0135] [Table 1]

[0136] [ka]

[0137] Pentaerythritol tetrakis(3-mercaptopropionate): [ka]

[0138] These results show that the presence of both an adhesion promoter and a vinyl polymer is essential to obtain a fluoropolymer layer that exhibits high adhesive performance even after 14 days of immersion in aqueous solution.

[0139] They also show that the silicon-free thio compounds are not efficient in obtaining fluoropolymer layers that exhibit high adhesive performance even after 14 days of immersion in aqueous solutions.

[0140] The dielectric properties of the adhesion-improved layer were compared to one of a single layer of fluoropolymer. Test samples were prepared according to the following protocol: 1. A polymer layer was coated onto a metal foil and cured as described above. 2. A mask containing several circular holes was placed on top of the polymer film. 3. The stack was placed inside a metallizer where evaporated gold could be applied onto the unmasked film to create conductive pads of defined surface area. 4. The actual surface of each pad was then measured under a microscope. 5. The capacitance C and dissipation factor tan δ of each pad at different frequencies (1, 10, 50 and 100 kHz) were determined using a GWIntek LCR-819 instrument (see Figure 1).

[0141] The dielectric constant, ε, indicates the tendency of a material to store electrical energy in an electric field. It essentially defines how a material responds to an electric field and describes the polarizability of a dielectric material: a material with a high dielectric constant will polarize more in response to an applied electric field than a material with a low dielectric constant, thereby storing more energy in the material. It is a fundamental property of electromagnetism and plays an important role in designing capacitors, insulators, and other electronic devices.

[0142] The loss factor tan δ quantifies the energy loss in a dielectric material when subjected to an AC electric field. It represents the energy loss due to dissipative effects within the material, such as dielectric conductivity and dipole orientation.

[0143] Relative permittivity ε r was calculated by the following formula:

number

[0144] Each measurement was repeated 15 to 18 times and the average values ​​of the dielectric constant and loss factor were calculated. The results are summarized in the table below showing the average values:

[0145] [Table 2]

[0146] These results show that all of these layers, whether containing fluoropolymer alone, or a mixture of fluoropolymer and silicon-sulfur compound, or a mixture of fluoropolymer, silicon-sulfur compound, and vinyl compound, have reasonably similar dielectric properties. Surprisingly, the presence of the silicon-sulfur compound and vinyl compound does not change the dielectric properties of the fluoropolymer, even though they have no dielectric properties of their own.

[0147] These results indicate that the adhesion promoter not only provides better adhesion and avoids delamination after immersion in water, but also limits the decrease in dielectric constant.

[0148] Such monolayers can therefore withstand humidity, immersion in water, or contact with other liquids and still be responsive in electronic applications such as actuators (devices that convert electrical energy into mechanical motion), sensors (devices that sense changes in the environment and convert them into electrical signals), or energy storage (electrodes and membranes in batteries and supercapacitors).

[0149] Example 2 - Effect of Solvent Properties Several compositions were prepared according to the following protocol (each step is carried out at room temperature): 1 / Weigh out the solvent (variable, 125 mL or 250 mL volume) into a vial. 2 / The fluoropolymer (P(VDF-TrFE-CTFE)) is weighed into the same vial and the mixture is stirred for 30 minutes and then left to stand for 1 hour. 3 / The silicon-sulfur compound (MPMDMS) and vinyl polymer (PMMA) are weighed into a vial, the mixture is stirred for 10 minutes, and then left to stand until all air bubbles have disappeared. The total content of "active ingredients" (fluoropolymer, thiosilane compound, and vinyl polymer) is 10 or 15% by weight. The solid content of non-solvent compounds relative to the weight of the solvent is expressed as % by weight of MS.

[0150] For each composition, the solubility was assessed visually after blending the components of the composition in a planetary mixer for 1.5 hours.

[0151] The viscosity of some of these compositions also varied at a shear rate of 10 s -1 The viscosity was evaluated at 23°C using standard laboratory methods using a cone-and-plate rheometer.

[0152] The solvent properties of each composition and the associated results are summarized in Table 2.

[0153] [Table 3]

Claims

1. a fluoropolymer; a silicon-sulfur compound, a vinyl polymer consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms, - with a solvent or a mixture of solvents A composition comprising:

2. 2. The composition of claim 1, wherein the sum of the mass contents of the fluoropolymer, the silicon-sulfur compound, and the vinyl polymer is between 5% and 30% based on the total mass of the composition.

3. The fluoropolymer has the following formula (I): C(X １ )(X ２ )=C(X ３ )(X ４ ) (I) (In the formula, X １ , X ２ , X ３ , and X ４ are each independently selected from H, Cl, Br, F, I, and optionally partially or fully halogenated C1-C6 linear or branched alkyl groups, with the proviso that X １ , X ２ , X ３ , and X ４ and provided that at least one of the groups contains at least one fluorine atom. The composition of claim 1 , comprising units derived from a fluoromonomer of the formula:

4. The fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer, and a third fluoromonomer, with the proviso that the second and third fluoromonomers are different from vinylidene fluoride and different from each other, and the second and third fluoromonomers have the following formula (I): C(X １ )(X ２ )=C(X ３ )(X ４ ) (I) (In the formula, X １ , X ２ , X ３ and X ４ are each independently selected from H, Cl, Br, F, I, and optionally partially or fully halogenated C1-C6 linear or branched alkyl groups, with the proviso that X １ , X ２ , X ３ , and X ４ and provided that at least one of the groups contains at least one fluorine atom. The composition of claim 1 , wherein the monomer is

5. The composition of claim 1 comprising from 3% to 30% by weight of the fluoropolymer, based on the total weight of the composition.

6. The silicon-sulfur compound is represented by the following formula (II): (Rd)S-Rw-Si(Ra)(Rb)(Rc) (II) wherein Rw is a linear, branched or cyclic group containing 1 to 18 carbon atoms and optionally one or several oxygen and / or nitrogen atoms; Ra, Rb and Rc are each independently selected from H, OH, Alk and -O-Alk, where Alk is a C1-C8 linear or branched alkyl group; and Rd is selected from the group consisting of H and organic moieties containing 1 to 30 carbon atoms and at least one nitrogen and / or at least one oxygen atom.

2. The composition of claim 1, wherein the compound is

7. 10. The composition of claim 1, comprising 0.05% to 0.3% by weight of the silicon-sulfur compound, based on the total weight of the composition.

8. 10. The composition of claim 1, wherein the vinyl polymer comprises units derived from a vinyl monomer of formula C(X)(X')=C(X'')(X'''), wherein X, X', X'' and X''' are independently selected from the group consisting of a hydrogen atom, an OH group, a COOH group, a CN group, an aromatic group, a saturated or unsaturated hydrocarbon group containing from 1 to 10 carbon atoms, the aromatic group or the hydrocarbon group optionally further comprising an OH group, an ester group, a carboxyl group, an amine group, a nitrile group, and / or an amide group.

9. The vinyl polymer has the following formula (III): 【Chemistry 1】 wherein Xa and Xb are independently selected from H, a —CN group, and a C1-C8 linear, branched, or cyclic, saturated or unsaturated group containing 1 to 8 carbon atoms; and Xc is selected from H, a benzyl group, and a linear, branched, or cyclic, saturated or unsaturated aliphatic or aromatic group containing 1 to 24 carbon atoms, optionally substituted with at least one OH group and / or one COOH group, and / or optionally interrupted by at least one —O— atom.

2. The composition of claim 1, wherein the polymer is an acrylate polymer comprising units derived from an acrylate monomer of formula:

10. The composition of claim 1, comprising from 0.05% to 0.3% by weight of the vinyl polymer, based on the total weight of the composition.

11. 10. The composition of claim 1, wherein the solvent has a boiling point between 95°C and 180°C at atmospheric pressure.

12. 2. The composition of claim 1, wherein the solvent is an oxyhydrocarbonated solvent, preferably an oxyhydrocarbonated solvent containing from 3 to 7 carbon atoms.

13. The composition of claim 1 , wherein the solvent comprises at least one ester or ketone functional group.

14. 2. The composition of claim 1, exhibiting a viscosity between 10 and 20,000 cP, preferably between 100 and 10,000 cP.

15. A method for making the composition of any one of claims 1 to 14, comprising the step of mixing a fluoropolymer, a silicon-sulfur compound, and a vinyl polymer in a solvent.

16. 15. A method for producing a coated substrate, comprising applying a composition according to any one of claims 1 to 14 to a surface or part of a surface of a substrate, followed by evaporating the solvent.

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