Substrate comprising a surface covered with an epilame agent and method for coating such a substrate with epilame

Abstract

The invention relates to a substrate comprising a surface which is at least partially covered with an epilame agent, characterised in that the epilame agent comprises at least one compound in the form of a copolymer comprising units M and units N, joined by covalent bonds by their main chains, where, in M and N, R1 and R2, which are identical or different, are H, a C1-C10 alkyl group, a C2-C10 alkenyl group; X and Y, which are identical or different, are spacer arms consisting of a heteroatom or of a hydrocarbon chain containing at least one linear or branched heteroatom, comprising at least one carbon atom, or X is a chemical bond directly connecting the group L to the main chain of the unit N; A, which is identical or different, constitutes an anchoring group for anchoring to the substrate; L, which is identical or different, is a phenyl group comprising at least one halogen atom or a -CHy(C6HzX5-z)3-y group, where X is a halogen atom, y is 0, 1 or 2, and z is 0, 1, 2, 3 or 4. The invention also relates to a method for coating such a substrate with epilame, and to a timepiece or piece of jewellery comprising a component that includes such a substrate.

Description

SUBSTRATE COMPRISING A SURFACE COATED WITH A HAIR-REMOVAL AGENT AND A METHOD FOR HAIR-REMOVAL OF SUCH A SUBSTRATE Technical field of the invention

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

[0002] Various processes exist for modifying the surface condition of a substrate by treating it with a suitable agent to specifically improve certain surface properties. For example, in the mechanical engineering field, and particularly in watchmaking, but also in jewelry making, the surface of a part or component is often treated with an epilame agent to control and reduce its surface energy during use. More specifically, an epilame agent aims to prevent the spreading of oils or lubricants on the components of a watch or jewelry piece by forming a hydrophobic and oleophobic surface that allows the lubricant to remain in a predetermined area of ​​the treated surface.

[0003] However, the substances currently used for depilation have several drawbacks. For example, depilation agents such as Fixodrop® ES / BS from Moebius® or the Novec™ range from 3M™ have insufficient resistance to watchmaking washes.

[0004] US patent application US2012 / 0088099 partially solves this problem by proposing the use of an epilame agent carrying a catechol group at the end of its chain. This catechol group is capable of binding firmly to the surface of certain substrates, but does not offer improved resistance to watchmaking washes for substrates such as gold and steel, which are very common substrates in the field of watchmaking or jewelry. Thus, the use of known epilating agents is generally limited to certain materials, which obliges the user to have different types of epilating agents at their disposal 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 a mixture of different compounds (thiol and bisphosphonic) as the epilame composition, the synergistic effect of which promotes the adhesion of the epilame to the substrate. However, the synthesis of each of these compounds requires at least four steps, making the synthesis process for the entire epilame composition lengthy 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 including a fluorinated motif, an anchoring motif, and optionally an additional hydrocarbon chain. Patent EP 3 070 152 describes an epilame agent comprising a block copolymer including a fluorinated motif, an anchoring motif, and optionally an additional hydrocarbon chain. The disclosed fluorinated motifs are linear perfluorinated alkyl chains of the type -CXF2X+I, specifically -CeF and -CsFi?.

[0007] It is known that epilators containing linear chains of the type -CXF2X+I pose environmental and health problems related to per- and polyfluoroalkyl substances (PFAS), particularly perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). These linear (per)fluorinated chains can be transformed into persistent PFAS during their manufacture or degradation in the environment. PFAS, and especially PFOA and PFOS, are extremely stable, persistent in the environment, and accumulate in living organisms (bioaccumulation), with toxic effects. Furthermore, many PFAS, such as PFOA and PFOS, are molecules that, upon degradation, decompose into acid Trifluoroacetic acid (TFA) is water-soluble. Therefore, it easily contaminates water resources, making purification complex. Because of these impacts, international regulations are increasingly restricting the use of PFAS, as well as any substance that can be transformed into PFAS, including linear (per)fluorinated chains. Summary of the invention

[0008] The invention aims in particular to overcome the various drawbacks of known hair removal agents and hair removal processes.

[0009] More specifically, one objective of the invention is to provide an epilame agent that is not subject to general regulatory pressure related to environmental concerns. In particular, the invention aims to provide an epilame agent comprising groups exhibiting low, or even (almost) non-existent, persistence in the environment, and / or a very low propensity to accumulate in living organisms.

[0010] Another objective of the invention is to provide an epilame agent that is simpler to purify and recycle, thereby reducing the risk of accumulation in the environment compared to epilame agents comprising linear (per)fluorinated chains.

[0011] The invention also aims to provide an epilame agent offering excellent resistance to washing, particularly to the washing processes used in watchmaking. The invention further aims to provide a universal epilame agent that can be used on (applied to and adhered to) any type of material.

[0012] The invention also aims to provide an environmentally friendly hair removal process that eliminates the use of a significant amount of polluting fluorinated solvents. The invention also aims to provide an economical hair removal process that eliminates the use of a significant amount of expensive fluorinated solvents.

[0013] The invention also aims to provide an epilame agent and an epilame process which allow precise knowledge of the epilame agent concentration over time, in order to provide robustness to the overall epilame process.

[0014] To this end, a first aspect of the present invention relates to a substrate comprising a surface of which at least a part is coated with an epilame agent according to the attached claims.

[0015] 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 by their main chains.

[0016] According to the invention, M is Ri, identical or different, is H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, and preferably H or methyl (CH3), 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 a grouping of anchors to the substrate.

[0017] According to the invention, N is Fb, identical or different, is H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, and preferably H or methyl (CH3), 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, or is a chemical bond directly linking the L group to the main chain of the N unit, and L, whether identical or different, is a grouping according to formula (I) or according to formula (II): -CeHxQs-x (I), where Q is a halogen atom, and x is 0, 1, 2, 3, or 4; or -CHy(C6HzQ'5-z)3-y (II), WHERE Q' is a halogen atom, y is 0 or 1, and z is 0, 1, 2, 3 or 4.

[0018] The L group according to formula (I) is a phenyl group comprising at least one halogen atom. The L group according to formula (II) is a group comprising at least two phenyl groups, each of which comprises at least one halogen atom.

[0019] Advantageously, at least one halogen atom in the L group, that is, at least one Q atom in formula (I) or at least one Q' atom in formula (II), is a fluorine atom. In other words, L is advantageously a group that is at least partially fluorinated.

[0020] Advantageously, when the L group is according to formula (I), Q is F and x is 0, that is, the L group is advantageously perfluorophenyl (-CeFs), also called pentafluorophenyl.

[0021] Advantageously, when the L group is according to formula (II), Q' is F and z is 0, that is, the L group is advantageously a group comprising two or three perfluorophenyl (pentafluorophenyl) groups: bis(perfluorophenyl)methyl or tri(perfluorophenyl)methyl.

[0022] The inventors discovered that the L groups according to formula (I) and formula (II) do not transform into molecules comprising at least one -CF3 group or at least one -CF2 group, either during their manufacture or during their degradation in the environment. With regard to European regulations and the OECD definition (see, e.g., the scientific article "A New OECD Definition for Per- and Polyfluoroalkyl Substances," Wang, Buser, et al., Environ. Sci. Technol. 2021, 55, 15575-15578), PFAS are molecules comprising at least one -CF3 group or at least one -CF2 group (per- and polyfluoroalkyl type groups). It therefore follows that the L groups according to the present invention do not transform into PFAS, particularly into TFA. This is confirmed by the European Union's draft PFAS restriction, e.g., version 14 of June 24, 2025. i does not mention L groups as being problematic. Consequently, these groups exhibit significantly reduced persistence in the environment and a lower tendency to accumulate in living organisms compared to known groups, particularly linear (per)fluorinated chains. This helps to reduce environmental and health impacts.

[0023] Advantageously, the copolymer is a statistical copolymer. Advantageously, the M units and the N units are randomly distributed. Advantageously, the copolymer is a statistical copolymer and the M units and the N units are randomly distributed.

[0024] 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.

[0025] Advantageously, and optionally, the copolymer according to this disclosure further comprises a P unit, where P is Rs, identical or different, is H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, and preferably H or methyl (CH3), and Rs, identical or different, is H, CH3, a hydrocarbon chain that may contain at least one heteroatom, linear or branched, saturated or unsaturated, comprising at least two carbon atoms.

[0026] Advantageously, when the copolymer comprises at least one P unit, the P unit (the units) and the M units and the N units are associated by covalent bonds through their main chains.

[0027] Advantageously, the functional grouping of interest Rs, whether identical or different, is -B or -WB, where W, 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 B, whether identical or different, constitutes a hydrophilic group.

[0028] Advantageously, B, whether identical or different, is a polyether group -((CH2)aO)p-Re, where Re is H, an alkyl group at C1-C10, an alkenyl group at C2-C10, and preferably H or CH3, a is chosen between 1 and 6, preferably between 2 and 3, and [3 is chosen between 1 and 30, preferably between 2 and 20.

[0029] The inventors have surprisingly discovered that if the epilame agent comprises at least one P unit where Rs is -B or -WB, with W and B as described above, the epilame agent is at least partially, and preferably completely, soluble in water. More specifically, the copolymer is at least partially, and preferably completely, soluble in water. Without being limited to this, the inventors believe that this excellent water solubility is a result of the specific composition of the copolymer, and that the polyether B group contributes to the solubility of the copolymer, and advantageously of the epilame agent, in water. This enables the use of aqueous epilame processes, thus eliminating the need to use polluting organic solvents.

[0030] Advantageously, the surface of the substrate, at least a portion of which is coated 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 their alloys. An example of such a metal alloy, particularly valued in the watchmaking industry, is the NiP alloy.

[0031] A second aspect of the present invention relates to a method of depilating at least part of a surface of a substrate according to the attached claims.

[0032] The depilation process according to the present invention comprises preparing a depilation agent comprising at least one copolymer as defined above. Optionally, the depilation process further comprises preparing the substrate surface. The depilation process further comprises contacting the substrate surface with the depilation agent.

[0033] Advantageously, the epilame agent is prepared (the preparation of the epilame agent includes the copolymerization of monomers capable of forming M units with monomers capable of forming N units and Optionally with monomers capable of forming P units. Advantageously, the M units, N units, and optional P units are as described above. Advantageously, the monomers are selected from the group comprising acrylate, methacrylate, acrylamides, methacrylamides, vinyl, and styrenic monomers.

[0034] According to one embodiment of the depilation process, the preparation of the depilation agent includes the preparation of a depilation bath containing the depilation agent. Then, at least a portion of the substrate surface is brought into contact with the depilation agent in the depilation bath, for example by immersing the substrate in the depilation bath.

[0035] According to another embodiment of the epilaming process, the substrate surface is brought into contact with the epilaming agent by placing the substrate and the epilaming agent in a chamber at ambient pressure, followed by hermetically sealing the chamber. Then, CO2 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 chamber. The pressure in the chamber is then reduced, and the epilamed substrate is removed from the chamber.

[0036] A third aspect of the present invention relates to the use of a copolymer comprising M units, N units, and optionally P units, covalently linked by their chains, as an epilame agent for at least a portion of a substrate surface. The M units, N units, and optional P units are as described above.

[0037] The present invention further relates to a watch or jewelry item comprising an element having a substrate according to the first aspect of the present invention. Detailed description of the invention

[0038] According to the present invention, a substrate comprises a surface, at least a portion of which is coated with an epilame agent. Advantageously, at least the surface of the substrate, and optionally the entire substrate, 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 their alloys.

[0039] Advantageously, the substrate surface comprises or substantially consists of a metallic alloy. A preferred example of a metallic alloy, particularly valued in watchmaking, is NiP, an alloy consisting primarily of nickel and phosphorus. NiP may have a low phosphorus content (typically between 2% and 5% by weight), a medium phosphorus content (typically between 6% and 9% by weight), or a high phosphorus content (typically between 10% and 13% by weight, for example, 12% by weight).

[0040] Alternatively, and advantageously, the substrate surface may comprise or substantially consist of (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 undoped, of 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, and their alloys.

[0041] Advantageously, in the present invention, the substrate is a substrate of an element of a watch or jewelry part.

[0042] The epilame agent comprises at least one compound in the form of a copolymer comprising M units and N units, where M is and N is

[0043] The M units and these N units are associated by covalent bonds through their main chains.

[0044] Advantageously, Ri and Fb, whether identical or different, are H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, and preferably H or an alkyl group in C1-C6, more preferably H or a group in C1-C4, for example H, methyl or ethyl.

[0045] Advantageously, group X, identical or different, is a non-cleavable spacer arm. Advantageously, group X, identical or different, is selected from a group comprising C1-C20 ester groups, preferably C2-C10, more preferably C2-C6, and even more preferably C2-C5, preferably alkyl ester groups, preferably linear, amide groups, and styrene-derived groups. Optionally, X, identical or different, comprises at least one heteroatom. Alternatively and advantageously, group X, identical or different, is a chemical bond directly linking group L to the main chain of unit N.

[0046] Advantageously, the Y group, identical or different, is a non-cleavable spacer arm. Advantageously, the Y group, identical or different, is chosen from the group comprising ester groups in C1-C20, preferably in C2-C10, more preferably in C2-C6, and even more preferably in C2-C5, preferably alkyl ester groups, preferably linear, amide groups, and styrene-derived groups. Optionally, Y, identical or different, includes at least one heteroatom.

[0047] The functional groups of interest A are capable of reacting with the surface of the substrate to be epilamated, so as to form anchoring groups of the epilamating agent to the substrate surface. Advantageously, A groups may also be provided at the ends of the copolymer. Advantageously, the copolymer comprises at least two different A groups.

[0048] 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.

[0049] The functional groups of interest L are responsible for the epilame effect. They comprise at least one halogen atom, particularly fluorine, iodine, bromine, or chlorine. Preferably, the halogen atom is fluorine. If the L group comprises multiple halogen atoms, the atoms may be identical or different. Advantageously, all the halogen atoms in the L group are fluorine.

[0050] The functional groups of interest L include one, two, or three phenyl groups comprising at least one halogen atom, preferably fluorine. Such a phenyl group can be denoted as -CeHxQs-x, where Q is a halogen atom, preferably fluorine (F), and x is 0, 1, 2, 3, or 4. Advantageously, x is 0, and each hydrogen atom in the phenyl group is therefore replaced by a halogen atom, preferably fluorine. In other words, the phenyl group is advantageously a perhalogenated phenyl group (-CeQs), preferably a perfluorinated phenyl group (-CeFs), also called a perfluorophenyl or pentafluorophenyl group.

[0051] Advantageously, the L group is a group according to formula (I), comprising a phenyl group: -CeHxQs-x (I), where Q is a halogen atom, preferably fluorine; and x is 0, 1, 2, 3 or 4.

[0052] Advantageously, the L group according to formula (I) is a perfluorophenyl (pentafluorophenyl) group, in which Q is F and x is 0, having the following structure (III), in which X is the spacer arm described above: (III).

[0053] Alternatively and advantageously, the L group is a group according to formula (II), comprising two or three phenyl groups: -CH y (C6HzQ'5-z)3-y (II), where Q' is a halogen atom, preferably fluorine; y is 0 or 1; and z is 0, 1, 2, 3 or 4.

[0054] Advantageously, the L group according to formula (II) is a group whose phenyl groups are perfluorophenyl groups, in which Q' is F and z is 0.

[0055] Preferred examples of L groups according to formula (II) are bis(perfluorophenyl)methyl having structure (IV) and tris(perfluorophenyl)methyl having structure (V), in which X is the spacer arm described above: (V).

[0056] Advantageously, and optionally, the copolymer according to this disclosure further comprises a P unit, where P is

[0057] Advantageously, R3, identical or different, is H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, and preferably H or an alkyl group in C1-C2, more preferably H or a group in C1-C4, for example H, methyl or ethyl.

[0058] Advantageously, the functional groups of interest Rs allow for modification of the properties of the epilame agent and / or the provision of additional functions. For example, Rs can be an alkyl chain used to modify the contact angle obtained or a chain capable of forming crosslinking points during a complementary crosslinking step.

[0059] Advantageously, Rs, identical or different, is H, CH3, a hydrocarbon chain that may contain at least one heteroatom, linear or branched, saturated or unsaturated, comprising at least two carbon atoms.

[0060] Advantageously, the functional grouping of interest Rs, whether identical or different, is -B or -WB, where W, 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 B, whether identical or different, constitutes a hydrophilic group.

[0061] Advantageously, the W group, whether identical or different, is a non-cleavable spacer arm. Advantageously, the W group, whether identical or different, is selected from a group comprising ester groups in the C1-C20 group, preferably in the C2-C10 group, more preferably in the C2-C6 group, and even more preferably in the C2-C5 group, preferably alkyl ester groups, preferably linear groups, amide groups, and styrene-derived groups. Optionally, W, whether identical or different, comprises at least one heteroatom.

[0062] Advantageously, group B is responsible for the solubility of the copolymer in water. Advantageously, the functional group of interest B comprises between 1 and 30, preferably between 2 and 20, ether groups. That is, the functional group of interest B is a polyether.

[0063] Advantageously, the ether group comprises between 1 and 6, preferably between 2 and 3, CH2 groups. For example, when a is 2, the ether group is of the ethyl ether type (CH2CH2O). For example, when a is 4, the ether group is of the butyl ether type (CH2CH2CH2CH2O).

[0064] Advantageously, B, whether identical or different, is a group -((CH2)aO)p-Re, where Re is H, an alkyl group at C1-C10, an alkenyl group at C2-C10, and preferably H or CH3, a is chosen between 1 and 6, preferably between 2 and 3, and [3 is chosen between 1 and 30, preferably between 2 and 20.

[0065] Advantageously, the copolymer comprises between 1% and 50%, preferably between 2% and 40%, and more preferably between 5% and 20% of M units, the percentage being expressed as a percentage of the total number of units in the copolymer. Advantageously, the copolymer comprises between 20% and 99%, preferably between 25% and 95%, and more preferably between 40% and 88% of N units, the percentage being expressed as a percentage of the total number of units in the copolymer. When it consists (comprises only) of M units and N units, the copolymer has a sum of the percentages of M units and N units equal to 100%.

[0066] Advantageously, when the copolymer comprises P units, it comprises between 1% and 50%, preferably between 5% and 50%, and more preferably between 10% and 45% of P units, the percentage being expressed in relation to the total number of units in the copolymer.

[0067] Advantageously, when the copolymer comprises M units, N units, and P units, it advantageously comprises between 2% and 40% M units, between 25% and 95% N units, and between 1% and 50% P units, preferably between 5% and 20% M units, between 40% and 85% N units, and between 10% and 45% P units, each percentage being expressed as a proportion of the total number of units in the copolymer. When the copolymer consists (comprises only) of M units, N units, and P units, the percentages of M units, N units, and P units are such that the sum of the percentages of M units, N units, and P units equals 100%.

[0068] Advantageously, and optionally, the copolymer according to this disclosure further comprises at least one V unit, where V is

[0069] Advantageously, R4, identical or different, is H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, and preferably H or a C1-C6 alkyl group, more preferably H or a C1-C4 group, for example H, methyl or ethyl.

[0070] Advantageously, the Z group, whether identical or different, is a non-cleavable spacer arm. Advantageously, the Z group, whether 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.

[0071] Advantageously, the Z group, identical or different, is chosen from the group comprising ester groups in C1-C20, preferably in C2-C10, more preferably in C2-C6, and even more preferably in C2-C5, preferably alkyl ester groups, preferably linear, amide groups, and styrene-derived groups. Optionally, Z, identical or different, comprises at least one heteroatom.

[0072] Advantageously, the T group, identical or different, is a tracer group arranged to determine the concentration of epilame agent in an epilame bath.

[0073] Advantageously, the T group allows, for example, the determination of the copolymer concentration by spectroscopy.

[0074] Advantageously, T, identical or different, is a UV-absorbing group derived from a compound selected from the group comprising benzotriazoles, triazines, and phenes (notably benzophenone, acetophenone, hydroxyalkylphenone, hydroxyarylphenone, amino alkylphenone, and anthraquinone), and acyl-phosphine oxides.

[0075] Advantageously, T, identical or different, is a fluorophore group derived from a compound selected from the group comprising fluorescein, a naphthyl, anthracene, coumarin, rhodamine, and a fluorobenzoate.

[0076] Advantageously, when the copolymer comprises at least one V unit, the V unit(s) and the M and N units are associated by covalent bonds via their main chains. Advantageously, when the copolymer comprises at least one P unit and at least one V unit, the P unit(s), the V unit(s), the M and N units are associated by covalent bonds via their main chains.

[0077] Advantageously, the copolymer comprises between 5 and 500 units, preferably between 10 and 350 units.

[0078] The copolymer can be a statistical copolymer or a block copolymer.

[0079] Advantageously, when the copolymer is a statistical copolymer, the M, N, P optional units, and V optional units are randomly distributed. In other words, the units are statistically linked to each other by their main chain.

[0080] Advantageously, when the copolymer is a block copolymer, the copolymer comprises at least one block of M units covalently linked by their main chains, and at least one block of N units covalently linked by their main chains. Advantageously, the blocks are connected to each other by covalent bonds via their main chains in linear sequences. Preferably, the block copolymer comprises a single block of M units and / or a single block of N units.

[0081] Optionally, the block copolymer further comprises at least one block of P units covalently linked by their main chains. Preferably and optionally, the block copolymer comprises a single block of P units.

[0082] Optionally, at least one of the M block, the N block, and the optional P block may include at least one V unit, covalently linked by 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 includes at least one V unit, at least one of the M block, the N block, and the optional P block must include at least one V unit, and the number of V units in the M block may vary from the number of V units in the N block and from the number of V units in the P block if the latter is included in the block copolymer.

[0083] Preferably, the V units are integrated and distributed within the block composed of the N units, for example by statistical copolymerization of V units with N units to form a single block consisting mainly of N units and assimilated to a block of N units.

[0084] The present invention also relates to a method of depilating at least a part of a substrate surface comprising the preparation of a depilating agent, optionally the preparation of the substrate surface, and bringing the substrate surface into contact with the depilating agent.

[0085] Advantageously, the preparation of the epilame agent includes the copolymerization of monomers capable of forming M units with monomers capable of forming N units, optionally monomers capable of forming at least one P unit, and optionally monomers capable of forming at least one V unit.

[0086] Advantageously, the monomers are chosen from the group comprising acrylate, methacrylate, acrylamides, methacrylamides, vinyl, diene, styrene and olefinic monomers.

[0087] Monomers particularly preferred for forming N units comprising a perfluorophenyl group according to formula (I), in which Q is F and x is 0, include pentafluorophenyl acrylate (CAS 71195-85-2), pentafluorophenyl methacrylate (CAS 13642-97-2), pentafluorobenzyl acrylate (CAS 153614-61-0), pentafluorobenzyl methacrylate (CAS 114859-23-3) and 2,3,4,5,6-pentafluorostyrene (CAS 653-34-9).A person skilled in the art will understand that pentafluorophenyl acrylate results in an M unit comprising C(O)O as the X group and H as the Fb group; pentafluorophenyl methacrylate results in an M unit comprising C(O)O as the X group and CH3 as the R2 group; pentafluorobenzyl acrylate results in an M unit comprising C(O)OCH3 as the X group and H as the R2 group; pentafluorobenzyl methacrylate results in an M unit comprising C(O)OCH3 as the X group and CH3 as the R2 group; and pentafluorostyrene results in an M unit comprising a direct bond between the L group and the main chain as the X group and H as the R2 group.

[0088] These monomers can be obtained by transformation of molecules such as pentafluorophenyl alcohols, e.g. pentafluorophenyl methanol (CAS 440-60-8, also known as pentafluorobenzyl alcohol) and pentafluorophenyl ethanol (CAS 653-31-6).

[0089] Monomers for forming N units comprising two perfluorophenyl groups linked by a carbon atom according to formula (II), in which Q' is F, z is 0 and y is 1, can be obtained by transformation of molecules such as decafluorobenzhydrol (CAS 1766-76-3, also known as bis(perfluorophenyl)methanol), the decafluorobenzhydryl chloride (CAS 5736-48-1) and decafluorobenzhydryl bromide (CAS 5736-49-2).

[0090] Monomers to form N units comprising three perfluorophenyl groups linked by a carbon atom according to formula (II), in which Q' is F, z is 0 and y is 0, can be obtained by transformation of molecules such as tris(perfluorophenyl)methanol (CAS 4893-33-8), tris(perfluorophenyl)methyl chloride (CAS 2254241-27-3), tris(perfluorophenyl)methyl bromide and tris(perfluorophenyl)methyl iodide.Other examples of monomers and monomer-transferable molecules capable of forming N-units comprising three perfluorophenyl groups linked by a carbon atom according to formula (II), in which Q' is F, z is 0, and y is 0, include (2,4,6-triethylbenzene-1,3,5-triyl)tris((perfluorophenyl)methanol) (CAS 1189949-26-5), (2,4-difluoro-6-vinylbenzene-1,3,5-triyl)tris((perfluorophenyl)sulfane) (CAS 676515-08-5), and 6,6',6"-((2,4-difluoro-6-vinylbenzene-1,3,5-triyl)tris(oxy))tris(1,2,3,4,5-pentafluorobenzene) (CAS 676515-05-2) and 3,5-difluoro-2,4,6-tris(perfluorophenoxy)benzoic acid (CAS 185697-22-7).

[0091] The transformation of molecules into monomers capable of forming N units can be done by processes known in chemistry.

[0092] Polymerization techniques include those known to those skilled in the art. Optionally, copolymerization is carried out in the presence of an initiator, such as, but not limited to, azobisisobutyronitrile (AIBN). Optionally, copolymerization is carried out at an elevated temperature. For example, polymerization can be performed in solution, using suitable solvents such as ketones (e.g., butanone or cyclohexanone), at a moderate temperature (e.g., between 70 °C and 80 °C), under an inert atmosphere (preferably argon).

[0093] The copolymers used in the present invention can be obtained in powder or viscous liquid form.

[0094] A particularly suitable polymerization method for obtaining a statistical copolymer is free radical copolymerization, in solution or in emulsion.

[0095] 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 P unit, - of monomers capable of forming at least one block of N units and optionally with monomers capable of forming at least one P unit, P being identical or different, and - optionally with monomers capable of forming at least one block of V units and optionally with monomers capable of forming at least one P unit, P being identical or different.

[0096] According to a first copolymerization method, the copolymer can be obtained in a single step by copolymerization, preferably radical, of monomers bearing Y-A side chains with monomers bearing XL side chains, optionally monomers bearing ZT side chains, and optionally monomers bearing Rs side chains.

[0097] According to another copolymerization method, the copolymer can be obtained by copolymerization, preferably radical copolymerization, of monomers bearing the appropriate Y side chains with monomers bearing the appropriate X side chains, optionally with monomers bearing the appropriate Z side chains, and optionally with monomers bearing side chains intended to carry Rs, then the side chains are modified, for example by "click chemistry", to introduce the functional groups of interest A, L, T (optionally), and the Rs groups (optionally).

[0098] Advantageously, when the copolymerization is a free-radical copolymerization, the free-radical copolymerization is either "free" or "controlled" to obtain a statistical copolymer. Advantageously, the free-radical copolymerization is "controlled" to obtain a block copolymer.

[0099] Optional substrate surface preparation may include cleaning and / or washing the surface to be epilaminated. Such cleaning or washing may be carried out using methods known to those skilled in the art. For example, and particularly when the substrate is a watch component, cleaning may include standard watchmaking procedures.

[0100] Alternatively, substrate surface preparation can include CO2 treatment at a temperature between 10°C and 80°C and a pressure between 25 bar and 250 bar, for example, for a duration of 1 to 60 minutes. Such treatment advantageously removes dust particles and degreases the surface.

[0101] Advantageously, the copolymer(s) are dissolved in an organic solvent or a combination of two or more organic solvents. Advantageously, the organic solvent does not contain groups of the type -CF2 and -CF3. In other words, the organic solvent is advantageously a non-PFAS organic solvent (according to the definition of PFAS mentioned above).

[0102] The non-PFAS organic solvent may contain one or more halogen atoms, particularly fluorine. Advantageously, the non-PFAS organic solvent is a hydrochloroolefin, for example (1Z)-1-Chloro-2,3,3-trifluoroprop-1-ene (CAS 1263679-68-0) and (E)-1-chloro-2,3,3-trifluoroprop-1-ene (CAS 1263679-71-5).

[0103] Advantageously, the organic solvent is non-halogenated. Non-limiting examples of non-halogenated organic solvents include water, acetone, and alcohols such as methanol and ethanol.

[0104] Advantageously, the copolymer(s) are dissolved in the organic solvent at concentrations preferably between 50 mg / L and 1 g / L to obtain a solution of the epilame agent. Naturally, the optimal concentration depends on the composition of the copolymer and the organic solvent used.

[0105] According to a first embodiment of the epilaming process, such a solution of epilaming agent 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 for maintaining the concentration of the epilaming agent are provided in order to control and optionally maintain this concentration over time, and preferably before contacting the substrate surface with the epilaming agent in the epilaming bath.

[0106] Such concentration control methods 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 allows for control of the epilame agent concentration in the epilame bath.

[0107] Advantageously, when the T group is a UV absorber or a fluorophore, the concentration of the epilame agent is determined by spectroscopy (e.g., absorbance measurement). An intermediate step, prior to the step of controlling the concentration of the epilame agent in the epilaming bath, involves developing a calibration curve for the copolymer. For this, the copolymer is dissolved at different concentrations in a solvent, and for each solution, the absorbance is measured spectroscopically as a function of The wavelength. The wavelength at which the absorbance is maximum is identified, and then the calibration curve A = F(concentration) is plotted at the wavelength at which the absorbance is maximum. The molar extinction coefficient of the polymer can then be deduced (Beer-Lambert law A=scl).

[0108] To control the concentration of epilame in the epilame bath, simply measure the absorbance of the bath solution using spectroscopy, and then, using the previously established calibration curve, deduce the concentration of epilame in the bath. Depending on the result, additional epilame can then be added to the bath to precisely readjust the concentration.

[0109] The depilating process according to the invention may further include, after contacting the surface of the substrate with the depilating agent, a drying step of the depilated surface.

[0110] According to a second embodiment of the epilaming process, the epilame agent solution as described above is used (including being placed) in a chamber. Alternatively, the epilame agent can be placed in the chamber in its pure form.

[0111] 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.

[0112] Next, CO2 is introduced into the hermetically sealed enclosure. Advantageously, the CO2 is introduced for a period of between 1 and 30 minutes, preferably between 1 and 20 minutes, and more preferably between 3 and 15 minutes.

[0113] Advantageously, 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.

[0114] Advantageously, 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.

[0115] Then, the introduction of CO2 is stopped and the pressure in the chamber is reduced. Advantageously, the pressure is reduced to ambient pressure, i.e., a pressure between 0.6 bar and 1.1 bar.

[0116] Then, the epilame substrate was removed from the enclosure.

[0117] Optionally, after the pressure in the chamber has been reduced and the epilaminated substrate has been removed from the chamber, the epilaminated substrate can be heat-treated. For example, the epilaminated substrate can be heated in the chamber to a temperature between 250 °C and 90 °C, preferably between 30 °C and 80 °C, for a duration of between 1 and 45 minutes, preferably between 2 and 30 minutes. Such heat treatment improves the adhesion of the epilaminated agent to the surface of the treated substrate.

[0118] The de-icing process according to the invention may further comprise, after contacting the substrate surface with the de-icing agent, a complementary crosslinking step. This complementary crosslinking is advantageously made possible by the presence of the appropriate functional groups of interest provided on the Rs side chains of the U units. Example 1

[0119] An epilamate agent was produced by copolymerization. The monomer 2,3,4,5,6-pentafluorostyrene (CAS 653-34-9; R2 being H, X being a chemical bond, and L being CeFs) was copolymerized with the monomer 2-(methylthio)ethyl methacrylate (CAS 14216-23-0; Ri being CH3, Y being C(O)O, A being (CH2)2SCH3), in the presence of tetrahydrofuran and azobisisobutyronitrile (AIBN) under an argon atmosphere. The medium The reaction mixture was heated to 80 °C with stirring for four hours. The copolymer was recovered by precipitating the reaction mixture in methanol and then washed twice with fresh methanol.

[0120] This copolymer according to the present invention was then deposited onto the surface of three different substrates: steel, sapphire, and gold. The surfaces had previously undergone surface preparation treatment. The deposition was carried out using an aqueous deposition bath.

[0121] In order to evaluate the properties of the epilames agents, various tests were carried out.

[0122] To evaluate the performance of this epilame agent, the contact angle was measured with Moebius® 9010 oil. Drops of oil were deposited, and the contact angles were measured using an optical instrument (Dataphysics OCA 15). To assess resistance to watchmaking washes, the substrates were washed three times using a watchmaking wash (amine hydrocarbon solution), followed by measurement of the contact angles.

[0123] Table 1 shows the results on different substrates for the inventive copolymer. Table 1: Contact angles before and after watch washing

[0124] The contact angles of 9010 oil droplets deposited on uncoated substrates were not measurable after complete droplet spreading. Since it is possible to measure the contact angles for each substrate coated with the epilame agent, both before and after watch washings, an epilame effect as well as resistance to watch washings are demonstrated.

[0125] The copolymer was also tested for solubility in fluorinated solvents, including hydrofluoroethers (HFEs), hydrofluorocarbons (HFCs), and hydrofluoroolefins (HFOs). For this purpose, the copolymer was added to HFE-7200 solvent and AMOLEA™ AS-300AT solvent, and it was observed that the copolymer did not dissolve. The copolymer was also added to water, and its dissolution was observed. Example 2

[0126] An epilame agent was produced by copolymerization. 0.67 mL (0.9998 g, 3.75 mmol) of pentafluorobenzyl methacrylate monomer (CAS 114859-23-3; Fb being H, X being C(O)OCH2, and L being CeFs) was copolymerized with 2-(methylthio)ethyl methacrylate monomer (CAS 14216-23-0; Ri being CH3, Y being C(O)O, A being (CH2)2SCH3) in the presence of tetrahydrofuran and azobisisobutyronitrile (AIBN) under an argon atmosphere. The reaction mixture was heated to 80 °C with stirring for four hours. The copolymer was recovered by precipitating the reaction mixture in methanol and then washed twice with fresh methanol. The mass yield was 87%.

[0127] This copolymer according to the present invention was then deposited on the surface of the three substrates of Example 1 and the contact angle was measured as described in Example 1.

[0128] Table 2 shows the results on different substrates for the inventive copolymer. Table 2: Contact angles before and after watch washing

[0129] The contact angles of 9010 oil droplets deposited on uncoated substrates were not measurable after complete spread of the droplet. Since it is possible to measure the contact angles for each substrate coated with the epilame agent both before and after watchmaking washes, an epilame effect and resistance to watchmaking washes are demonstrated.

Claims

DEMANDS 1. A substrate comprising a surface at least a part of which is coated with an epilame agent, characterized in that said epilame agent comprises at least one compound in the form of a copolymer comprising M units and N units, associated by covalent bonds through their main chains, where M is , N is , where Ri and R2, whether identical or different, are H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, and preferably H or CH3, 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, or is a chemical bond directly linking the L group to the main chain of the N unit, 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, A, whether identical or different, constitutes a grouping that anchors to the substrate. L, whether identical or different, is a grouping according to formula (I) or according to formula (II): -CeHxQs-x (I), where Q is a halogen atom, preferably fluorine, and x is 0, 1, 2, 3, or 4; or -CHy(C6HzQ'5-z)3-y (II), WHERE Q' is a halogen atom, preferably fluorine, y is 0 or 1, and z is 0, 1, 2, 3 or 4.

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

3. The substrate according to any one of the preceding claims, characterized in that L is a grouping according to formula (I), in which Q is F and x is 0.

4. The substrate according to any one of claims 1 to 2, characterized in that L is a grouping according to formula (II), in which Q' is F and z is 0.

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

6. The substrate according to any one of the preceding claims, characterized in that the copolymer further comprises at least one P unit associated with the M and N units by covalent bonds through their main chains, R3, identical or different, is H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, and preferably H or CH3, and Rs, identical or different, is H, CH3, a hydrocarbon chain that may contain at least one heteroatom, linear or branched, saturated or unsaturated, comprising at least 2 carbon atoms.

7. The substrate according to claim 6, characterized in that Rs, identical or different, is -B or -WB, where W, 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 B, whether identical or different, is a hydrophilic group.

8. The substrate according to claim 7, characterized in that B is a polyether group -((CH2)aO)p-Re, where Re is H, an alkyl group at C1-C10, an alkenyl group at C2-C10, and preferably H or CH3, a is chosen between 1 and 6, preferably between 2 and 3, and [3 is chosen between 1 and 30, preferably between 2 and 20.

9. The substrate according to any one of the preceding claims, characterized in that its surface, at least a part of which is coated 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 their alloys, preferably NiP.

10. A process for removing at least part of a substrate surface comprising the steps of: - preparation of an epilame agent comprising at least one copolymer as defined in the preceding claims, - optionally, preparation of the substrate surface, - bringing the surface of the substrate into contact with the epilame agent.

11. The epilaming process according to claim 10, characterized in that the preparation of the epilaming agent comprises the copolymerization of monomers capable of forming M units with monomers capable of forming N units, and optionally with monomers capable of forming P units, preferably in which the monomers are selected from the group comprising acrylate, methacrylate, acrylamides, methacrylamides, vinyl and styrenic monomers.

12. The epilaming process according to any one of claims 10 to 11, characterized in that the preparation of the epilaming agent comprises the preparation of an epilaming bath containing the epilaming agent and that the surface of the substrate is brought into contact with the epilaming agent in said epilaming bath.

13. The epilaming process according to any one of claims 10 to 11, characterized in that the step of contacting the substrate surface with the epilaming agent comprises the steps of: - placement of the substrate and the epilame agent in a chamber at ambient pressure, - airtight seal of the enclosure, - introduction of CO2 into the hermetically sealed enclosure 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, - decrease in pressure within the enclosure, and - removal of the epilaminate substrate from the enclosure.

14. Use of a copolymer comprising M units and N units, associated by covalent bonds along their main chains, where My t, N is, where Ri and R2, whether identical or different, are H, an alkyl group at C1-C10, an alkenyl group at C2-C10, and preferably H or CH3, 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, or is a chemical bond directly linking the L group to the main chain of the N unit, 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, A, whether identical or different, constitutes a grouping that anchors to the substrate. L, whether identical or different, is a grouping according to formula (I) or according to formula (II): -CeHxQs-x (I), where Q is a halogen atom, preferably fluorine, and x is 0, 1, 2, 3, or 4; or -CHy(C6HzQ'5-z)3-y (II), WHERE Q' is a halogen atom, preferably fluorine, y is 0 or 1, and z is 0, 1, 2, 3 or 4, as an epilame agent of at least a part of a substrate surface.

15. A watch or jewelry item comprising an element having a substrate according to any one of claims 1 to 9.

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