Substrate having a surface coated with an epilating agent and method for epilating such a substrate

Description

Technical field of the invention

[0001] The present invention relates to a substrate comprising a surface at least a portion of which is covered with an epilame agent. The invention also relates to methods of epilame-ing such a substrate. Technological background

[0002] There are various methods for modifying the surface condition of a substrate by treatment with a suitable agent so as to specifically improve certain surface properties. For example, in the field of mechanics, and in particular in the field of watchmaking, but also in the field of jewelry, the epilaming of a surface of a part or element is often carried out using an epilame agent in order to control and reduce the surface energy of said surface during its use. More particularly, an epilame agent is intended to prevent the spreading of oils or lubricants on the elements of a timepiece or jewelry piece by forming a hydrophobic and oleophobic surface allowing the lubricant to remain in a predetermined location on the treated surface.

[0003] However, the substances currently used for epilamation have various disadvantages. For example, epilamation agents such as Fixodrop ®< ES / BS from Moebius ®< or the Novec ™< range from 3M ™< have too low resistance to watch washing.

[0004] Patent application US2012 / 0088099 partially solves this problem by proposing to use an epilame agent carrying a catechol function at the end of the chain. This catechol function is capable of firmly attaching to the surface of certain substrates, but does not present improved resistance to watch washing for substrates such as gold and steel, which are very common substrates in the field of watchmaking or jewelry. Thus, the use of known epilame agents is generally limited to certain materials, which requires the user to have different types of epilame agents available depending on the nature of the surfaces to be treated.

[0005] A solution to this problem is described, for example, in patent application WO 2012 / 085130. This solution consists of using as an epilame composition a mixture of compounds of different nature (thiol and bisphosphonic) whose synergistic effect promotes the adhesion of epilame to the substrate. However, the synthesis of each of these compounds requires at least four steps, so the synthesis process for the entire epilame composition is long and complex.

[0006] Another solution is described for example in patents EP 3 070 133 and EP 3 070 152. Patent EP 3 070 133 describes an epilame agent comprising a random copolymer comprising a fluorinated unit, an anchoring unit and optionally an additional hydrocarbon chain. Patent EP 3 070 152 describes an epilame agent comprising a block copolymer comprising a fluorinated unit, an anchoring unit and optionally an additional hydrocarbon chain. In particular, fluorinated units of the type -C 5 F 11 and -C 6 F 13 are described.

[0007] However, perfluorohexanoic acid (PFHxA, CAS 307-24-4), its salts and related substances are under general regulatory pressure for environmental reasons. Summary of the invention

[0008] The invention aims in particular to overcome the various drawbacks of known epilame agents and epilame methods.

[0009] More specifically, an objective of the invention is to provide an epilame agent which is considered not to be under general regulatory pressure for environmental reasons.

[0010] The invention also aims to provide an epilame agent offering increased wash resistance compared to known epilame agents. The invention also aims to provide a universal epilame agent that can be used for any type of material.

[0011] The invention also aims to provide an environmentally friendly epilaming process that eliminates the use of a significant amount of polluting fluorinated solvents. The invention also aims to provide an economical epilaming process that eliminates the use of a significant amount of expensive fluorinated solvents.

[0012] The invention also aims to provide an epilame agent and an epilame method which make it possible to know precisely the concentration of epilame agent over time, in order to provide robustness to the overall epilame method.

[0013] To this end, a first aspect of the present invention relates to a substrate comprising a surface of which at least a portion is covered with an epilame agent according to the appended claims.

[0014] According to the invention, the epilame agent comprises at least one compound in the form of a copolymer comprising M units and N units. These M units and these N units are associated by covalent bonds through their main chains.

[0015] According to the invention, M is , Or R 1 , identical or different, is H, a C 1 -C 10 alkyl group, or a C 2 -C 10 alkenyl group, and preferably H or CH 3 , Y, identical or different, is a spacer arm consisting of a heteroatom or a hydrocarbon chain containing at least one heteroatom, linear or branched, comprising at least one carbon atom, and A, identical or different, constitutes an anchoring group to the substrate.

[0016] Advantageously, Y, identical or different, is chosen from the group comprising C 1 -C 20 ester groups, amide groups, and groups derived from styrene. Optionally, Y, identical or different, comprises at least one heteroatom.

[0017] Advantageously, A is chosen from the group comprising glycidyl, thiols, thioethers, thioesters, sulfides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, protected or unprotected phosphonic acids, protected or unprotected phosphonates, amines, ammoniums, nitrogen heterocycles, carboxylic acids, anhydrides, and catechols.

[0018] According to the invention, N is , Or R 2 , identical or different, is H, a C 1 -C 10 alkyl group, or a C 2 -C 10 alkenyl group, and preferably H or CH 3 , X, identical or different, is a spacer arm consisting of a heteroatom or a hydrocarbon chain containing at least one heteroatom, linear or branched, comprising at least one carbon atom, and L, identical or different, is a halogenated ether group according to formula (I) where Q is a halogen atom, P, identical or different, is a C 1 -C 10 alkyl group or a C 2 -C 10 alkenyl group comprising at least one halogen atom and being linear or branched, p is chosen between 1 and 4, preferably between 2 and 3, and n is chosen between 1 and 20, for example between 1 and 16, preferably between 1 and 10.

[0019] Advantageously, X, identical or different, is chosen from the group comprising C 1 -C 20 ester groups, amide groups, and groups derived from styrene. Optionally, X, identical or different, comprises at least one heteroatom.

[0020] Advantageously, L is an ether group which is at least partially fluorinated, for example fully fluorinated. The term "fully fluorinated" as used in the present disclosure indicates an ether group in which each hydrogen atom is replaced by a fluorine atom.

[0021] Advantageously, the copolymer is a random copolymer. Advantageously, the M units and the N units are randomly distributed. Advantageously, the copolymer is a random copolymer and the M units and the N units are randomly distributed.

[0022] Alternatively, and also advantageously, the copolymer is a block copolymer. Advantageously, the block copolymer comprises at least one block of M units associated by covalent bonds through their main chains, and at least one block of N units associated by covalent bonds through their main chains. Advantageously, the blocks are connected to each other by covalent bonds through their main chains in linear sequences.

[0023] Advantageously, the ratio of N units / M units is between 1 and 20, for example between 2 and 18, or between 5 and 15.

[0024] Advantageously, and optionally, the copolymer according to the present disclosure further comprises V units. Advantageously, the V units are associated with the M and N units by covalent bonds through their main chains. Advantageously, V is Or R 4 , identical or different, is H, a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group, preferably H or CH 3 , Z, identical or different, is a spacer arm consisting of a heteroatom or a hydrocarbon chain containing at least one heteroatom, linear or branched, comprising at least one carbon atom, and T, identical or different, is a tracer group arranged to determine the concentration of epilame agent in an epilame bath.

[0025] Advantageously, T, identical or different, is a UV absorbing group or a fluorophore.

[0026] Advantageously, the surface of the substrate, at least part of which is covered with the epilame agent, is made of a material chosen from the group comprising metals, metal oxides, polymers, sapphire, ruby, silicon, silicon oxides, silicon nitrides, silicon carbides, diamond like carbon (DLC), and their alloys.

[0027] A second aspect of the present invention relates to a method of epilaming at least a portion of a surface of a substrate according to the appended claims.

[0028] The epilaming method according to the present invention comprises the preparation of an epilaming agent comprising at least one copolymer as defined above. Optionally, the epilaming method further comprises the preparation of the surface of the substrate. The epilaming method further comprises the bet in contact of the substrate surface with the epilame agent.

[0029] Advantageously, the epilame agent is prepared (the preparation of the epilame agent is carried out) by copolymerization of monomers capable of forming the M units with monomers capable of forming the N units. Advantageously, the M units and the N units are as described above. Advantageously, the monomers are chosen from the group comprising acrylate, methacrylate, acrylamide, methacrylamide, vinyl and styrenic monomers.

[0030] According to one embodiment of the epilaming method, the epilaming agent is prepared by preparing an epilaming bath containing the epilaming agent. Then, at least a portion of the surface of the substrate is brought into contact with the epilaming agent in the epilaming bath, for example by immersing the substrate in the epilaming bath.

[0031] This preparation of the epilame agent is particularly suitable when the epilame agent comprises at least one copolymer further comprising V units associated with the M and N units by covalent bonds via their main chains. Advantageously, the V units are as described above. The presence of the V units, and in particular of the tracer group, advantageously and optionally makes it possible to control, before contacting, the concentration of epilame agent in the epilaming bath. Optionally and after having controlled the concentration of the epilame agent, the concentration of epilame agent in the epilaming bath can be readjusted.

[0032] According to another embodiment of the epilaming process, the surface of the substrate is brought into contact with the epilaming agent by placing the substrate and the epilaming agent in an enclosure at ambient pressure, followed by hermetically sealing the enclosure. Then, ofCO2 at a pressure between 25 bar and 74 bar, preferably between 45 bar and 70 bar, and at a temperature between 10 °C and 80 °C, preferably between 15 °C and 50 °C is introduced into the hermetically sealed enclosure. Then, the pressure in the enclosure is reduced and the epilaminated substrate is removed from the enclosure.

[0033] A third aspect of the present invention relates to the use of a copolymer comprising M units and N units, associated by covalent bonds by their chains as an epilame agent for at least a portion of a surface of a substrate. The M units and the N units are as described above.

[0034] A timepiece or piece of jewelry may thus comprise an element comprising a substrate according to the first aspect of the present invention.

[0035] One of the advantages of the epilame agents according to the present invention is that they are not under regulatory pressure for environmental reasons, although they offer a high-performance epilame effect. Another advantage is that they are resistant to washing, particularly watch washing. Brief description of the figures

[0036] The purposes, advantages and characteristics are demonstrated in the following figures, which are not limiting, and in which: there Figure 1 represents the structure of a perfluoroether monomer, the Figure 2 represents the structure of a monomer comprising an anchoring group, the Figure 3 represents the structure of an epilame copolymer according to the invention, the Figure 4 represents the contact angles measured on different substrates whose surface is covered with an epilame agent according to the invention, the Figure 5represents the contact angles measured on different substrates whose surface is covered with an epilame agent of the C6F13 type, the Figure 6 represents the contact angles measured on different substrates whose surface is coated with a competing epilame agent. Detailed description of the invention

[0037] According to the present invention, a substrate comprises a surface of which at least a portion is covered with an epilame agent. Advantageously, at least the surface of the substrate, and optionally the entire substrate, is made of a material chosen from the group comprising metals, metal oxides, polymers, sapphire, ruby, silicon, silicon oxides, silicon nitrides, silicon carbides, diamond like carbon (DLC), and their alloys.

[0038] More specifically, the surface of the substrate may comprise or be made of steel, or of noble metals such as gold, rhodium, palladium, platinum, or combinations of two or more of them, or of metal oxides, doped or not with aluminum, zirconium, titanium, chromium, manganese, magnesium, iron, nickel, copper, zinc, molybdenum, silver, tungsten, or combinations of two or more of them, or of polyoxymethylene or acrylamide, as well as their alloys.

[0039] Advantageously, in the present invention, the substrate is a substrate of an element of a timepiece or piece of jewelry.

[0040] Advantageously, the group X, identical or different, is chosen from the group comprising C 1 -C 20 ester groups, preferably C 2 -C 10 , more preferably C 2 -C 6 , and even more preferably C 2 -C 5 , preferably alkyl ester groups, preferably linear, amide groups, and groups derived from styrene.

[0041] Advantageously, the group Y, identical or different, is chosen from the group comprising C 1 -C 20 ester groups, preferably C 2 -C 10 , more preferably C 2 -C 6 , and even more preferably C 2 -C 5 , preferably alkyl ester groups, preferably linear, amide groups, and groups derived from styrene.

[0042] Advantageously, the copolymer comprises at least two different A groups. The functional groups of interest A are capable of reacting with the surface of the substrate to be epilamated, so as to constitute anchoring groups of the epilamating agent to the surface of the substrate. Advantageously, A groups may also be provided at the end of the copolymer.

[0043] The functional groups of interest L are responsible for the epilame effect. They comprise at least one halogen atom Q. Advantageously, the halogen atom Q, which may be identical or different, is a fluorine atom, an iodine atom, a bromine atom, or a chlorine atom. Preferably, the halogen atom is a fluorine atom. If the group L comprises several halogen atoms, the atoms may be identical or different. Advantageously, all the halogen atoms Q of the group L are fluorine atoms.

[0044] The functional groups of interest L also comprise a group P. The group P, which may be identical or different, is advantageously a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group or a C 2 -C 10 alkynyl group. The group P advantageously comprises at least one halogen atom. Advantageously, the halogen atom, which may be identical or different, is a fluorine atom, an iodine atom, a bromine atom or a chlorine atom. Preferably, the halogen atom is a fluorine atom. The group P may be linear or branched.

[0045] Advantageously, the group P is a C 1 -C 10 perfluoroalkyl group, preferably a C 1 -C 6 perfluoroalkyl group, for example a C 1 -C 4 perfluoroalkyl group, such as CF 3 , C 2 F 5 , C 3 F 7 or C 4 F 9 .

[0046] Advantageously and alternatively, the group P is a C 2 -C 10 perfluoroalkenyl group, preferably a C 2 -C 6 perfluoroalkenyl group, for example a C 2 -C 4 perfluoroalkenyl group, such as C 2 F 3 , C 3 F 5 and C 4 F 7 .

[0047] Advantageously and alternatively, the group P is a C 2 -C 10 perfluoroalkynyl group, preferably a C 2 -C 6 perfluoroalkynyl group, for example a C 2 -C 4 perfluoroalkynyl group, such as C 2 F, C 3 F 3 , and C 4 F 5 .

[0048] Advantageously, in the functional group of interest L, p is chosen between 1 and 4, preferably between 2 and 3.

[0049] Advantageously, in the functional group of interest L, n is chosen between 1 and 20, for example between 1 and 16, preferably between 1 and 10, for example between 2 and 8.

[0050] A preferred functional group of interest L in the present invention is represented by the structure (CF(CF 3 )OCF 2 ) n CF 2 CF 3 , i.e., Q is a fluorine atom (F), P is CF 3 , and p is 2. More particularly, a preferred structure of the group L is (CF(CF 3 )OCF 2 ) 5 CF 2 CF 3 , i.e., Q is a fluorine atom (F), P is CF 3 , p is 2, and n is 5.

[0051] One of the copolymers preferably used in the present invention represents the following structure (II)

[0052] In other words, in this copolymer X is C(O)O(CH 2 ) 2 OC(O); Y is C(O)O; P is fluorine (F); Q is CF 3 ; and p is 2, which indicates that L is (CF(CF 3 )OCF 2 ) n CF 2 CF 3 . Preferably, in the copolymer represented by structure (II), R 1 and R 2 , the same or different, are H or CH 3 .

[0053] A particular example of this copolymer shown by structure (II), without being limiting, is a copolymer in which n is 5, R 1 is H, R 2 is CH 3 , A is CH 2 (CHCH 2 O), and the m / p ratio is 9.

[0054] Optionally, the copolymer may further comprise at least one U unit, where U is , Or R 3 , identical or different, is H, a C 1 -C 10 alkyl group, or a C 2 -C 10 alkenyl group, and preferably H or CH 3 , and R 5 , identical or different, is H, CH 3 , a hydrocarbon chain which may contain at least one heteroatom, linear or branched, saturated or unsaturated, comprising at least 2 carbon atoms.

[0055] Advantageously, when the copolymer comprises at least one U unit, the U unit and the M units and the N units are associated by covalent bonds through their main chains.

[0056] Advantageously, the functional groups of interest R 5 make it possible to modify the properties of the epilame agent and / or to provide other functions. For example, R 5 can be an alkyl chain used to modify the contact angle obtained, or can be a chain capable of constituting crosslinking points during a complementary crosslinking step.

[0057] Advantageously, the ratio of N units / M units is between 1 and 20, preferably between 2 and 18, for example between 5 and 15, or between 7 and 12, for example 8, 9, 10, or 11.

[0058] Advantageously, the copolymer comprises between 0.1% and 50%, preferably between 5% and 30%, and more preferably between 5% and 20% of M units, the percentage being expressed relative to the total number of units in the copolymer. Advantageously, the copolymer comprises between 1% and 99.9%, preferably between 50% and 99.9%, and more preferably between 80% and 95% of N units, the percentage being expressed relative to the total number of units in the copolymer. Advantageously, the copolymer comprises between 0% and 50%, preferably between 0% and 30%, and more preferably between 0% and 10% of U units, the percentage being expressed relative to the total number of units in the copolymer.

[0059] Optionally, the copolymer may further comprise at least one V unit, where V is as described above. Advantageously, when the copolymer comprises at least one V unit, the V unit and the M units and the N units are associated by covalent bonds through their main chains.

[0060] Advantageously, the group Z, identical or different, is chosen from the group comprising C 1 -C 20 ester groups, preferably C 2 -C 10, more preferably C 2 -C 6, and even more preferably C 2 -C 5, preferably alkyl ester groups, preferably linear, amide groups, and groups derived from styrene.

[0061] Advantageously, the T group makes it possible, for example, to determine the copolymer concentration by spectroscopy.

[0062] Advantageously, T, identical or different, is a UV absorber group derived from a compound chosen from the group comprising benzotriazoles, triazines, phenones (in particular benzophenone, acetophenone, hydroxyalkylphenone, hydroxyarylphenone, amino alkylphenone, and anthraquinone), and acylphosphine oxides.

[0063] Advantageously, T, identical or different, is a fluorophore group derived from a compound chosen from the group comprising fluoroscein, a naphthyl, anthracene, coumarin, rhodamine, and a fluorobenzoate.

[0064] Advantageously, the copolymer comprises between 5 and 500 units, preferably between 10 and 350 units.

[0065] The copolymer can be a random copolymer or a block copolymer.

[0066] Advantageously, when the copolymer is a statistical copolymer, the M, N units, the optional V units and the optional U units are distributed randomly. In other words, the units are linked together statistically by their main chain.

[0067] Advantageously, when the copolymer is a block copolymer, the copolymer comprises at least one block of M units associated by covalent bonds through their main chains, and at least one block of N units associated by covalent bonds through their main chains. Preferably, the block copolymer comprises a single block of M units and / or a single block of N units.

[0068] Optionally, the block copolymer further comprises at least one block of V units associated by covalent bonds through their main chains. Preferably and optionally, the block copolymer comprises a single block of V units.

[0069] Optionally, at least one of the block of units M, the block of units N and the optional block of units V optionally comprises at least one unit U, associated by covalent bonds through their main chains. Advantageously, the blocks are connected to each other by covalent bonds through their main chains in linear sequences. If the block copolymer further comprises at least one unit U, at least one of the block of units M, the block of units N and the optional block of units V comprises at least one unit U, and the number of units U in the block of units M may vary from the number of units U in the block of units N and from the number of units U in the block of units V if the latter is included in the block copolymer.

[0070] Preferably, the U units are integrated and distributed within the block composed of the N units, for example by random copolymerization of U units with the N units to form a single block consisting mainly of N units and assimilated to a block of N units.

[0071] The present invention also relates to a method of epilamating at least a portion of a surface of a substrate comprising preparing an epilamating agent, optionally preparing the surface of the substrate, and contacting the surface of the substrate with the epilamating agent.

[0072] Advantageously, the preparation of the epilame agent comprises the copolymerization of monomers capable of forming the M units with monomers capable of forming the N units, optionally monomers capable of forming at least one V unit, and optionally monomers capable of forming at least one U unit.

[0073] Advantageously, the monomers are chosen from the group comprising acrylate, methacrylate, acrylamide, methacrylamide, vinyl, diene, styrenic and olefinic monomers.

[0074] Particularly preferred monomers for forming the V units comprising a tracer group T are selected from the group comprising 2-H-benzotriazol-2-yl-hydroxyphenyl ethyl methacrylate, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-propenyl)phenol, 2-(4-benzoyl-3-hydroxyphenoxy)ethyl acrylate, 4-allyloxy-2-hydroxybenzophenone, 2-naphthyl (meth)acrylate, fluorescein O-(meth)acrylate, 9-anthracenylmethyl (meth)acrylate, ethidium bromide-N,N'-bisacrylamide, N-(1-naphthyl)-N-phenylmethacrylamide, and 7-[4-(trifluoromethyl)coumarin] methacrylamide. Such monomers are commercially available and are polymerizable.

[0075] Even more preferably, the monomers for forming the V units comprising a tracer group T are chosen from the group comprising 2-H-benzotriazol-2-yl-hydroxyphenyl ethyl methacrylate, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(2-propenyl)phenol, 2-(4-benzoyl-3-hydroxyphenoxy)ethyl acrylate, and 4-allyloxy-2-hydroxybenzophenone. These monomers comprise tracer groups which can be monitored by UV-visible spectroscopy, which is much easier to implement in an industrial environment than fluorescence spectroscopy.

[0076] Polymerization techniques include techniques known to those skilled in the art. Optionally, the copolymerization is carried out in the presence of an initiator, such as, but not limited to, azobisisobutyronitrile (AIBN). Optionally, the copolymerization is carried out at an elevated temperature.

[0077] The copolymers used in the present invention can be obtained in the form of powder or viscous liquid.

[0078] A particularly suitable polymerization method for obtaining a random copolymer is free radical copolymerization, in solution or in emulsion.

[0079] A particularly suitable polymerization method for obtaining a block copolymer is successive controlled radical copolymerization: of monomers capable of forming at least one block of M units and optionally with monomers capable of forming at least one U unit, of monomers capable of forming at least one block of N units and optionally with monomers capable of forming at least one U unit, U identical or different, and optionally of monomers capable of forming at least one block of V units and optionally with monomers capable of forming at least one U unit, U identical or different.

[0080] According to a first mode of copolymerization, the copolymer can be obtained in a single step by copolymerization, preferably radical, of monomers carrying Y-A side chains with monomers carrying XL side chains, optionally monomers carrying ZT side chains, and optionally monomers carrying Rs side chains.

[0081] According to another method of copolymerization, the copolymer can be obtained by copolymerization, preferably radical, of monomers carrying the appropriate Y side chains with monomers carrying the appropriate X side chains, optionally monomers carrying the appropriate Z side chains, and optionally monomers carrying side chains intended to carry R 5 , then the side chains are modified, for example by “click chemistry”, to introduce the functional groups of interest A, L, T (optionally), and the R 5 groups (optionally).

[0082] Advantageously, when the copolymerization is a radical copolymerization, the radical copolymerization is of the “free” type in order to obtain a random copolymer. Advantageously, the radical copolymerization is of the “controlled” type in order to obtain a block copolymer.

[0083] Optional preparation of the substrate surface may include cleaning and / or washing the surface to be epilaminated. Such cleaning or washing may be carried out according to methods known to those skilled in the art. For example, and in particular when the substrate is a watch component, the cleaning may include cleaning according to standard watchmaking methods.

[0084] Alternatively, the preparation of the substrate surface may include a CO 2 treatment at a temperature between 10 °C and 80 °C and a pressure between 25 bar and 250 bar, for example for a duration between 1 min and 60 min. Such treatment advantageously allows the removal of dust particles and the degreasing of the surface.

[0085] Advantageously, the copolymer(s) are dissolved in a fluorinated solvent, such as perfluorinated or fluorinated hydrocarbons, perfluoropolyethers, hydrofluoroolefins, hydrofluoroethers, at concentrations preferably between 50 mg / L and 1 g / L, in order to obtain a solution of epilame agent.

[0086] According to a first embodiment of the epilaming method, such an epilaming agent solution is then used in an epilaming bath. The same epilaming bath can be used several times. Advantageously, when the same epilaming bath is used several times, means for controlling and optionally means for maintaining the concentration of the epilaming agent are present in order to control and optionally maintain this concentration over time, and preferably before bringing the surface of the substrate into contact with the epilaming agent in the epilaming bath.

[0087] Such concentration control means may include the presence of at least one V unit as described above in the copolymer. In other words, the presence of at least one V unit comprising a T group as described above makes it possible to control the concentration of epilame agent in the epilame bath.

[0088] Advantageously, when the T group is a UV absorber group or a fluorophore, the determination of the concentration of epilame agent is carried out by spectroscopy (measurement of absorbance for example). An intermediate step, prior to the step of controlling the concentration of the epilame agent in the epilaming bath, provides for the development of a calibration curve of the copolymer. For this, the copolymer is dissolved at different concentrations in a solvent, and for each solution the absorbance is measured by spectroscopy as a function of the wavelength. The wavelength for which the absorbance is maximum is identified and then the calibration curve A = F(concentration) is plotted at the wavelength for which the absorbance is maximum. The molar extinction coefficient of the polymer can then be deduced from this (Beer Lambert law A=εcl).

[0089] To control the concentration of epilame agent in the epilaming bath, it is sufficient to measure the absorbance of the bath solution by spectroscopy, then using the previously established calibration curve to deduce the concentration of epilame agent in the bath. Depending on the result, additional epilame agent can then be added to the bath in order to precisely readjust the concentration.

[0090] The epilaming method according to the invention may further comprise, after bringing the surface of the substrate into contact with the epilaming agent, a step of drying the epilamed surface.

[0091] According to a second embodiment of the epilaming method, the epilaming agent solution as described above is used (including placed) in an enclosure. Alternatively, the epilaming agent may be placed in the enclosure in a pure form.

[0092] Advantageously, the substrate and the epilame agent are placed in an enclosure at ambient pressure, i.e. a pressure between 0.6 bar and 1.1 bar, followed by the hermetic closure of the enclosure.

[0093] Then, CO2 is introduced into the hermetically sealed enclosure. Advantageously, the CO2 is introduced for a period of between 1 min and 30 min, preferably between 1 min and 20 min, and more preferably between 3 min and 15 min.

[0094] Advantageously, the CO2 is at a pressure between 25 bar and 74 bar, preferably between 45 bar and 70 bar, and more preferably between 50 bar and 60 bar.

[0095] Advantageously, the CO2 is at a temperature between 10°C and 80°C, preferably between 10°C and 60°C, and more preferably between 15°C and 50°C.

[0096] Then, the introduction of CO2 is stopped and the pressure in the enclosure is reduced. Advantageously, the pressure is reduced to ambient pressure, i.e. a pressure between 0.6 bar and 1.1 bar.

[0097] Then, the epilaminated substrate is removed from the enclosure.

[0098] Optionally, after the pressure in the enclosure has decreased and the epilamated substrate has been removed from the enclosure, the epilamated substrate may be heat-treated. For example, the epilamated substrate may be heated in the enclosure to a temperature of between 250°C and 90°C, preferably between 30°C and 80°C for a period of between 1 min and 45 min, preferably between 2 min and 30 min. Such heat treatment makes it possible to improve the anchoring of the epilame agent to the surface of the treated substrate.

[0099] The epilaming method according to the invention may further comprise, after bringing the surface of the substrate into contact with the epilaming agent, a complementary crosslinking step. Complementary crosslinking is advantageously made possible by the presence of the appropriate functional groups of interest provided on the R 5 side chains of the U units. Examples Example 1

[0100] An epilame agent was produced by random copolymerization, resulting in a perfluoroether-type copolymer.

[0101] In a first step, a perfluoroether acrylate monomer ("perfluoroether monomer") was synthesized. Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl fluoride (CAS 13252-15-8) was reacted with 2-hydroxyethyl acrylate (CAS 818-61-1) in the presence of sodium fluoride and at room temperature. Figure 1represents the obtained monomer, in which n is 5 and R 1 is H (hydrogen).

[0102] The perfluoroether acrylate monomer was then copolymerized by random copolymerization with glycidyl methacrylate, shown in Figure 2 , A being CH 2 (CHCH 2 O) and R 2 being CH 3 (CAS 106-91-2), in the presence of the initiator AIBN. Figure 3 represents the obtained epilame copolymer, in which n is 5, R 1 is H, R 2 is CH 3 , A is CH 2 (CHCH 2 O) and in an m / p ratio of 9. Example 2

[0103] Three different epilame agents were deposited on the surface of a steel substrate, previously subjected to a surface preparation treatment, using an epilame bath. The first epilame agent is the copolymer synthesized in Example 1. The second epilame agent contains C6 perfluoroalkyl groups, i.e., C6F13 groups, as epilame groups. The third epilame agent is a competing epilame agent comprising methyl nonafluoroisobutyl ether (CAS 163702-08-7), methyl nonafluorobutyl ether (CAS 163702-07-6) and a fluoroaliphatic polymer.

[0104] In order to evaluate the properties of epilame agents, different tests were carried out.

[0105] As a first test, the surface energy was determined. The procedure, known to those skilled in the art, consists of measuring (using a Dataphysics OCA 15 contact angle measuring device) the contact angles of drops of 3 liquids. These are water, diiodomethane and ethylene glycol, each of which has very distinct surface tensions. From the angles obtained, the surface energy is calculated using the Owens, Wendt, Rabel and Kaelble (OWRK) method.

[0106] The results are shown in Table 1. The surface of the steel substrate without epilame agent, which underwent a surface preparation procedure, had a surface energy of 34.95 mN / m. All epilame agents show a reduction in surface energy, and the epilame agent of the invention shows the lowest value. The lower the surface energy, the better the oleophobicity. Table 1: Surface energy of different epilame agents Epilame agent Surface energy (mN / m) Epilame of the invention 18.44 Epilame type C 6 F 13 19.10 Epilame competitor 24.05 Example 3

[0107] The three epilame agents of Example 2 were then used (applied) to several substrates having different composition.

[0108] To evaluate the performance of the epilame agents, the contact angle was measured with test oil No. 3 and with oil 9010, from Moebius ®< . Drops of both oils were deposited and the contact angles were measured using an optical device (Dataphysics OCA 15). To evaluate the resistance to watch washing, the substrates were washed three times using a watch washing method (amino hydrocarbon solution), followed by the measurement of the contact angles.

[0109] The target values for each measure are as follows: Test oil no. 3 - initial (before washes): 60° Test oil no. 3 - after 3 washes: 35° Oil 9010 - initial: 70° Oil 9010 - after 3 washes: 45°

[0110] There Figure 4 represents the results on the different substrates for the inventive copolymer. The Figure 5 represents the results for the epilame agent of type C 6 F 13 , and the Figure 6 represents the results for the competing epilame agent.

[0111] It is clear from the Figure 6 that for none of the substrates are the target values aimed for each oil, before and after 3 washes, achieved. On the other hand, the target values aimed for oil 9010 are achieved with the copolymer according to the invention and the epilame agent of type C 6 F 13 . The target values aimed for oil no. 3 are achieved on certain substrates with these two epilame agents ( Figures 4 And 5 ).

Claims

1. A substrate comprising a surface at least a portion of which is covered with an epilame agent, characterised in that said epilame agent comprises at least one compound in the form of a copolymer comprising units M and units N, associated by covalent bonds via their main chains, where M is N is where R1 and R2, which may be identical or different, are H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, X and Y, which may be identical or different, are spacer arms consisting of a heteroatom or a linear or branched hydrocarbon chain containing at least one heteroatom and comprising at least one carbon atom, A, which may be identical or different, forms an anchoring group to the substrate, L, which may be identical or different, is a halogenated ether group according to formula (I) where Q is a halogen atom, P, which may be identical or different, is a C1-C10 alkyl group or a C2-C10 alkenyl group comprising at least one halogen atom and being linear or branched, p is chosen between 1 and 4, preferably between 2 and 3, and n is chosen between 1 and 20, preferably between 1 and 10.

2. The substrate according to claim 1, characterised in that the copolymer is a random copolymer and the units M and the units N are distributed randomly.

3. The substrate according to claim 1, characterised in that the copolymer is a block copolymer comprising at least one block of units M associated by covalent bonds via their main chains, and at least one block of units N associated by covalent bonds via their main chains, said blocks being bound together by covalent bonds via their main chains in linear sequences.

4. The substrate according to any one of the preceding claims, characterised in that L is an ether group which is at least a partially fluorinated, preferably totally fluorinated.

5. The substrate according to any one of the preceding claims, characterised in that A is selected from the group comprising glycidyl, thiols, thioethers, thioesters, sulphides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, protected or unprotected phosphonic acids, protected or unprotected phosphonates, amines, ammoniums, nitrogen heterocycles, carboxylic acids, anhydrides and catechols.

6. The substrate according to any one of the preceding claims, characterised in that X and Y, which may be identical or different, are selected from the group comprising C1-C20 ester groups, amide groups and groups derived from styrene, wherein X and Y, which may be identical or different, optionally comprise at least one heteroatom.

7. The substrate according to any one of the preceding claims, characterised in that the units N / units M ratio is between 1 and 20.

8. The substrate according to any one of the preceding claims, characterised in that the copolymer additionally comprises units V associated with the units M and N by covalent bonds via their main chains, where V is where R4, which may be identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, Z, which may be identical or different, is a spacer arm consisting of a heteroatom or a linear or branched hydrocarbon chain containing at least one heteroatom, comprising at least one carbon atom, and T, which may be identical or different, is a tracer group arranged to determine the concentration of epilame agent in an epilame-coating bath.

9. The substrate according to claim 8, characterised in that T, which may be identical or different, is a UV absorber group or a fluorophore.

10. The substrate according to any one of the preceding claims, characterised in that its surface, at least a portion of which is covered with the epilame agent, is made of a material selected from the group comprising metals, metal oxides, polymers, sapphire, ruby, silicon, silicon oxides, silicon nitrides, silicon carbides, diamond like carbon (DLC) and alloys thereof.

11. A method for epilame-coating at least a portion of a surface of a substrate comprising the steps of: - preparing an epilame agent comprising at least one copolymer as defined in the preceding claims, - optionally, preparing the surface of the substrate, - contacting the surface of the substrate with the epilame agent.

12. The method for epilame-coating according to claim 11, characterised in that the preparation of the epilame agent is carried out by copolymerisation of monomers capable of forming the units M with monomers capable of forming the units N, preferably wherein the monomers selected from the group comprising acrylate, methacrylate, acrylamide, methacrylamide, vinyl and styrene monomers.

13. The method for epilame-coating according to any one of claims 11 to 12, characterised in that the epilame agent comprises at least one copolymer as defined in claims 8 to 9, the epilame agent is prepared by preparing an epilame-coating bath containing the epilame agent, the surface of the substrate is contacted with the epilame agent in the epilame-coating bath, and the method optionally comprises, before contacting, a step of controlling the concentration of epilame agent in the epilame-coating bath by means of the tracer group and, optionally, a step of readjusting the concentration of epilame agent in the epilame-coating bath.

14. The epilame-coating method according to any one of claims 11 to 12, characterised in that the step of contacting the surface of the substrate with the epilame agent comprises the steps of: - placing the substrate and the epilame agent in an enclosure at ambient pressure, - hermetically sealing the enclosure, - CO2 at a pressure comprised between 25 bar and 74 bar, preferably between 45 bar and 70 bar, and at a temperature comprised between 10°C and 80°C, preferably between 15°C and 50°C is introduced into the hermetically sealed enclosure, - reducing the pressure in the enclosure, and - removing the epilame-coated substrate from the enclosure.

15. A use of a copolymer comprising units M and units N, associated by covalent bonds via their main chains, wherein M is N is , where R1 and R2, which may be identical or different, are H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, X and Y, which may be identical or different, are spacer arms consisting of a heteroatom or a linear or branched hydrocarbon chain containing at least one heteroatom and comprising at least one carbon atom, A, which may be identical or different, forms an anchoring group to the substrate, L, which may be identical or different, is a halogenated ether group according to formula (I) where Q is a halogen atom, P, which may be identical or different, is a C1-C10 alkyl group or a C2-C10 alkenyl group comprising at least one halogen atom and being linear or branched, p is chosen between 1 and 10, and n is chosen between 1 and 20, as an epilame agent of at least a portion of a surface of a substrate.