CH720410A2 - Substrate comprising a surface covered with an epilame agent and method of epilaming such a substrate - Google Patents

Abstract

The invention relates to a substrate comprising a surface of which at least part is covered 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 units N, associated by covalent bonds through their main chains, where M is N is where R 1 and R 2, identical or different, are H, a C 1 -C 10 alkyl group, a C 2 -C 10 alkenyl group; X and Y, identical or different, are spacer arms consisting of a heteroatom or a hydrocarbon chain containing at least one heteroatom, linear or branched, comprising at least one carbon atom; B, identical or different, constitutes a polyether group; L, identical or different, is a halogenated C 1 -C 6 carbon group or a halogenated ether group according to formula (I) where Q is a halogen atom; P, the same 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; and n is chosen between 1 and 20, and in which the copolymer is soluble in water. The invention also relates to a method for waxing such a substrate, as well as a timepiece or piece of jewelry comprising an element comprising such a substrate.

Description

Technical field of the invention

[0001] The present invention relates to a substrate comprising a surface of which at least part is covered with an epilame agent. The invention also relates to methods of epilaming such a substrate.

Technology background

[0002] There are different methods for modifying the surface state of a substrate by treatment using an appropriate 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 waxing of a surface of a part or an element is often carried out using means of an epilame agent in order to control and reduce the surface energy of said surface during its use. More particularly, an epilame agent aims to prevent the spreading of oils or lubricants on the elements of a timepiece or jewelry by forming a hydrophobic and oleophobic surface allowing the lubricant to remain at a predetermined location on the treated surface.

[0003] However, the substances currently used for hair removal have various drawbacks. For example, epilame 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 resolves 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 resolve 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 biphosphonic) whose synergistic effect promotes adhesion of the 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 a 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 -C5F11 and -C6F13 type are described.

[0007] Nevertheless, perfluorohexanoic acid (PFHxA, CAS 307-24-4), its salts and related substances are under general regulatory pressure for environmental reasons. Additionally, these epilame agents are typically applied to the surface of the substrate through the use of an epilame bath containing the epilame agent in solvents. The solvents used are also often fluorinated solvents. This makes the hair removal process polluting.

Summary of the invention

[0008] The invention aims in particular to overcome the various disadvantages of epilaming agents and known epilaming processes.

[0009] More precisely, 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 resistance to washing 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 ecological epilaming process making it possible to eliminate the use of polluting (fluorinated) solvents. The invention also aims to provide an economical epilaming process making it possible to eliminate the use of a significant quantity of expensive fluorinated solvents.

[0012] The invention also aims to provide an epilame agent as well as an epilame process which makes it possible to know precisely the concentration of epilame agent over time, in order to provide robustness to the overall process. epilamage.

[0013] To this end, a first aspect of the present invention relates to a substrate comprising a surface of which at least part 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 via their main chains. According to the invention, the copolymer is soluble in water.

[0015] According to the invention, M is where R1, identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or 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 B, identical or different, constitutes a polyether group.

Advantageously, Y, identical or different, is chosen from the group comprising C1-C20 ester groups, amide groups, and groups derived from styrene. Optionally, Y, identical or different, comprises at least one heteroatom.

Advantageously, B, identical or different, is a group -((CH2)αO)β-R3, where R3 is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, α is chosen between 1 and 6, preferably between 2 and 3, and β is chosen between 1 and 30, preferably between 2 and 20.

[0018] According to the invention, N is where R2, identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, 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, and L, identical or different, is a halogenated C1-C6 carbon group or a halogenated ether group according to formula (I) where Q is a halogen atom, P, 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,

Advantageously, X, identical or different, is chosen from the group comprising C1-C20 ester groups, amide groups, and groups derived from styrene. Optionally, X, identical or different, comprises at least one heteroatom.

Advantageously, L is a C1-C6 carbon group that is at least partially fluorinated, for example totally fluorinated. Alternatively and also advantageously, L is an ether group that is at least partially fluorinated, for example totally fluorinated. The term "fully fluorinated" as used in the present disclosure indicates a moiety in which each hydrogen atom is replaced by a fluorine atom.

It should be noted that the copolymer may comprise different L groups, for example a mixture of at least partially halogenated C1-C6 carbon groups and halogenated ether groups according to formula (I).

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

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 via their main chains, and at least one block of N units associated by covalent bonds via their main chains. Advantageously, the blocks are connected to each other by covalent bonds through their main chains in linear sequences.

Advantageously, the ratio of M units/N units is between 1:10 and 10:1, preferably between 1:5 and 5:1. The inventors discovered that the optimal ratio of M units/N units depends on the value of β. For example, when β is equal to a value between 8 and 10, for example 9, the optimal ratio of M units/N units is between 1:1 and 2:1, more particularly between 1:1 and 10:9 . For example, when β is equal to a value between 18 and 20, for example 19, the optimal ratio of M units/N units is between 1:5 and 3:5, more particularly between 2.5 and 1.2.

Advantageously, and optionally, the copolymer according to the present disclosure further comprises K units. Advantageously, the K units are associated with the M and N units by covalent bonds via their main chains. Advantageously, K is where R4, identical or different, is H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, and preferably H or CH3, 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 A, identical or different, constitutes an anchoring group to the substrate.

Advantageously, W, identical or different, is chosen from the group comprising C1-C20 ester groups, amide groups, and groups derived from styrene. Optionally, W, identical or different, comprises at least one heteroatom.

Advantageously, A is chosen from the group comprising glycidyl, thiols, thioethers, thioesters, sulphides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, phosphonic acids protected or not, phosphonates protected or not, amines , ammoniums, nitrogen heterocycles, carboxylic acids, anhydrides, and catechols.

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 via their main chains. Advantageously, V is where R5, identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, preferably H or CH3, 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 epilamage bath.

Advantageously, T, identical or different, is a UV absorber group or a fluorophore.

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.

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

The epilaming process according to the present invention comprises preparing an epilaming agent comprising at least one water-soluble copolymer as defined above. Optionally, the epilaming process further comprises preparing the surface of the substrate. The epilaming process further comprises contacting the surface of the substrate with the epilaming agent.

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 units N are as described above. Advantageously, the monomers are chosen from the group comprising acrylates, methacrylates, acrylamides, methacrylamides, vinyl and styrenic monomers.

[0034] According to one embodiment of the epilaming process, the epilaming agent is prepared by preparing an epilaming bath containing the epilaming agent. Advantageously, the epilamage bath is an aqueous epilamage bath containing the epilame agent dissolved in water. Then, at least part of the surface of the substrate is brought into contact with the epilaming agent in the aqueous epilamation bath, for example not immersing the substrate in the aqueous epilamation bath.

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 aqueous epilamation bath. Advantageously, this control is carried out by means of the tracer group. Optionally and after controlling the concentration of the epilame agent, the concentration of epilame agent in the aqueous epilamage bath can be readjusted.

[0036] According to another embodiment of the epilaming process, the surface of the substrate is brought into contact with the epilame agent by placing the substrate and the epilame agent in an enclosure at ambient pressure, followed by closing airtight seal of the enclosure. 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 enclosure closed hermetically. Then, the pressure in the enclosure is reduced and the epilamated substrate is removed from the enclosure.

[0037] A third aspect of the present invention relates to the use of a copolymer comprising M units and N units, associated by covalent bonds via their chains as an epilame agent for at least part of a surface of a substrate. M units and N units are as described above. The copolymer is soluble in water.

[0038] The present invention further relates to a timepiece or piece of jewelry comprising an element comprising a substrate according to the first aspect of the present invention.

[0039] 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 an efficient epilame effect. Another advantage is that the copolymer included in the epilame agent is water soluble, making fluorinated solvents redundant and offering a more environmentally friendly and often more economical alternative. Another advantage is that the epilame agents according to the present invention have excellent resistance to washing, in particular to watch washing.

Brief description of the figures

[0040] The aims, advantages and characteristics are demonstrated in the following figures, which are not limiting, and in which: – Figure 1 represents the structure of an epilame copolymer according to the invention, – Figure 2 represents the angles of contacts measured on different substrates whose surface is covered with an epilame agent according to the invention, – Figure 3 represents the contact angles measured on different substrates whose surface is covered with an epilame agent of the C6F13 type, – Figure 4 represents the contact angles measured on different substrates whose surface is covered with a competing epilame agent.

Detailed description of the invention

[0041] According to the present invention, a substrate comprises a surface of which at least part 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.

[0042] More precisely, 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 doped metal oxides. or not 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, as well than their alloys.

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

[0044] Advantageously, the group preferably alkyl ester groups, preferably linear, amide groups, and groups derived from styrene.

Advantageously, the Y group, identical or different, is chosen from the 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 groups derived from styrene.

The functional groups of interest B are hydrophilic groups. Advantageously, they are 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 to say, the functional group of interest B is a polyether.

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

The functional groups of interest L are responsible for the epilame effect. They include at least one halogen atom. Advantageously, the halogen atom, 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 L group includes several halogen atoms, the atoms can be identical or different. Advantageously, all the halogen atoms of the L group are fluorine atoms.

When the functional group of interest L is a halogenated C1-C6 carbon group, the group is preferably partially or totally halogenated. Advantageously, when L is a halogenated C1-C6 carbon group, L is an at least partially fluorinated C1-C6 carbon group, and preferably completely fluorinated. When L is a halogenated C1-C6 carbon group, L can also include a hydrogen atom on the terminal group.

When the functional group of interest L is a halogenated ether group, L also comprises a group P. The group P, identical or different, is advantageously a C1-C10 alkyl group, a C2-C10 alkenyl group or a C2-C10 alkynyl group. The P group advantageously comprises at least one halogen atom. Advantageously, the halogen atom, 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 P group can be linear or branched.

Advantageously, the group P is a C1-C10 perfluoroalkyl group, preferably a C1-C6 perfluoroalkyl group, for example a C1-C4 perfluoroalkyl group, such as CF3, C2F5, C3F7 or C4F9.

Advantageously and alternatively, the group P is a C2-C10 perfluoroalkenyl group, preferably a C2-C6 perfluoroalkenyl group, for example a C2-C4 perfluoroalkenyl group, such as C2F3, C3F5 and C4F7.

Advantageously and alternatively, the group P is a C2-C10 perfluoroalkynyl group, preferably a C2-C6 perfluoroalkynyl group, for example a C2-C4 perfluoroalkynyl group, such as C2F, C3F3, and C4F5.

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

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.

A functional group of interest L preferably in the present invention is represented by the structure C6F13.

Another functional group of interest L preferably in the present invention is represented by the structure (CF(CF3)OCF2)nCF2CF3, that is to say that Q is a fluorine atom (F), P is CF3, and p is 2. More particularly, a preferred structure of the L group is (CF(CF3)OCF2)5CF2CF3, that is to say that Q is a fluorine atom (F), P is CF3, p is 2, and n is 5.

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

[0059] In other words, in this copolymer (II) X is C(O)O(CH2)2; Y is C(O)O; L is (CF2)5CF3; α is 2, which indicates that B is ((CH2)2O)R3. Preferably, in the copolymer represented by structure (II), R1, R2 and R3, identical or different, are H or CH3.

[0060] A particular example of this copolymer presented by structure (II), without being limiting, is a copolymer in which R1 is CH3, R2 is CH3, R3 is CH3, and the m/p ratio is between 1:1 and 10:9 when the average value of β in the copolymer is between 8 and 10, and 3:7 when the average value of β in the copolymer is between 18 and 20.

Optionally, the copolymer may also comprise at least one K unit, where K is as described above. Advantageously, when the copolymer comprises at least one K unit, the K unit and the M units and the N units are associated by covalent bonds via their main chains.

Advantageously, the group W, identical or different, is chosen from the 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 groups derived from styrene.

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 epilame agent on the surface of the substrate. Advantageously, A groups can also be provided at the end of the copolymer.

[0064] Optionally, the copolymer may further comprise at least one U unit, where U is where R6, identical or different, is H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, and preferably H or CH3, and R7, identical or different, is H, CH3, a hydrocarbon chain which may contain at least one heteroatom, linear or branched, saturated or unsaturated, comprising at least 2 carbon atoms.

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 via their main chains.

[0066] Advantageously, the functional groups of interest R7 make it possible to modify the properties of the epilame agent and/or to provide other functions. For example, R7 may be an alkyl chain used to modify the contact angle obtained, or may be a chain capable of constituting crosslinking points during a complementary crosslinking step.

[0067] Advantageously, the copolymer comprises between 0% and 50%, preferably between 0.1% 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 100%, 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 K units, the percentage being expressed relative to the total number of units in the copolymer. .

Optionally, the copolymer may also 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 via their main chains.

[0069] Advantageously, the Z group, identical or different, is chosen from the 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 groups derived from styrene.

[0070] Advantageously, the T group makes it possible, for example, to determine the copolymer concentration by spectroscopy.

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 acyl-phosphine oxides.

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

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

The copolymer may be a random copolymer or a block copolymer.

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

[0076] Advantageously, when the copolymer is a block copolymer, the copolymer comprises at least one block of M units associated by covalent bonds via their main chains, and at least one block of N units associated by covalent bonds via their main chains. . Preferably, the block copolymer comprises a single block of M units and/or a single block of N units.

[0077] Optionally, the block copolymer further comprises at least one block of K units associated by covalent bonds via their main chains. Preferably and optionally, the block copolymer comprises a single block of K units.

[0078] Optionally, the block copolymer further comprises at least one block of V units associated by covalent bonds via their main chains. Preferably and optionally, the block copolymer comprises a single block of V units.

[0079] Optionally, at least one of the block of units M, of the block of units N, of the optional block of units K and of the optional block of units V optionally comprises at least one unit U, associated by links covalent 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 comprises at least one U unit, at least one of the block of M units, of the block of N units, of the optional block of K units and of the optional block of V units comprises at least a unit U, and the number of units U in the block of units M can vary from the number of units U in the block of units N, the number of units U in the block of units K, and the number of U units in the block of V units if the latter (K and V) are included in the block copolymer.

[0080] Preferably, the U units are integrated and distributed within the block composed of N units, for example by statistical 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.

[0081] The present invention also relates to a method for epilaming at least part of a surface of a substrate comprising the preparation of an epilame agent, optionally the preparation of the surface of the substrate, and the bringing into contact of the surface of the substrate with the epilame agent.

[0082] 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 K unit, optionally monomers capable of form at least one V unit, and optionally monomers capable of forming at least one U unit.

Advantageously, the monomers are chosen from the group comprising acrylates, methacrylates, acrylamides, methacrylamides, vinyl, diene, styrenic and olefinic monomers.

The particularly preferred 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, 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.

[0085] 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 contain tracer groups that can be monitored by UV-visible spectroscopy, which is much easier to set up in an industrial environment than fluorescence spectroscopy.

[0086] The 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, without limitation, azobisisobutyronitrile (AIBN). Optionally, the copolymerization is carried out at an elevated temperature.

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

[0088] A particularly suitable mode of polymerization to obtain a random copolymer is free radical copolymerization, in solution or in emulsion.

[0089] A particularly suitable mode of polymerization in order to obtain a block copolymer is the 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 , – monomers capable of forming at least one block of N units and optionally with monomers capable of forming at least one identical or different U, U unit, – optionally of monomers capable of forming at least one block of K units and optionally with monomers capable of forming at least one identical or different U, U unit, and – optionally with monomers capable of forming at least one block of V units and optionally with monomers capable of forming at least one identical U, U unit or different.

[0090] According to a first mode of copolymerization, the copolymer can be obtained in a single step by copolymerization, preferably radical, of monomers carrying Y-B side chains with monomers carrying X-L side chains, optionally monomers carrying W-A side chains. , optionally monomers carrying Z-T side chains, and optionally monomers carrying R7 side chains.

[0091] According to another mode 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 W side chains, optionally monomers carrying the appropriate Z side chains, and optionally monomers carrying side chains intended to carry R7, then the side chains are modified, for example by “click chemistry”, to introduce the functional groups of interest B, L , A (optionally), T (optionally), and groups R7 (optionally).

[0092] 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 root copolymerization is of the “controlled” type in order to obtain a block copolymer.

[0093] The optional preparation of the surface of the substrate may include cleaning and/or washing the surface to be epilaminated. Such cleaning or washing can 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, cleaning may include cleaning according to standard watchmaking processes.

[0094] Alternatively, the preparation of the surface of the substrate may include a treatment with CO2 at a temperature of between 10°C and 80°C and a pressure of between 25 bar and 250 bar, for example for a period of between 1 min and 60 mins. Such a treatment advantageously allows the elimination of dust particles and the degreasing of the surface.

Advantageously, the copolymer(s) are dissolved in water, at concentrations preferably between 50 mg/L and 1 g/L, in order to obtain a solution of epilame agent.

[0096] According to a first mode of execution of the depilaming process, such an epilamage agent solution is then used in a depilaming bath. The same hair removal bath can be used several times. Advantageously, when the same epilamage bath is used several times, control means and optionally means for maintaining the concentration of the epilame agent are present in order to control and optionally maintain this concentration over time, and to preferably before bringing the surface of the substrate into contact with the epilaming agent in the epilaming bath.

[0097] Such means of controlling the concentration 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.

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 epilame bath, provides for the development of a calibration curve for the copolymer. To do 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 wavelength. The wavelength for which the absorbance is maximum is identified 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 (Beer Lambert's law A=εcl).

[0099] To control the concentration of epilame agent in the epilame bath, it is then sufficient to measure the absorbance of the bath solution by spectroscopy, then using the previously established calibration curve to deduce the agent concentration. epilame in the bath. Depending on the result, additional epilame agent can then be added to the bath in order to precisely readjust the concentration.

[0100] The epilamation process according to the invention may further comprise, after bringing the surface of the substrate into contact with the epilame agent, a step of drying the epilame surface.

[0101] According to a second mode of execution of the epilaming process, the epilame agent solution as described above is used (including placed) in an enclosure. Alternatively, the epilame agent can be placed in the enclosure in a pure form.

[0102] Advantageously, the substrate and the epilame agent are placed in an enclosure at ambient pressure, i.e. a pressure of between 0.6 bar and 1.1 bar, followed by hermetic closing of the enclosure.

[0103] Then, CO2 is introduced into the hermetically closed 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.

[0104] Advantageously, the CO2 is at a pressure of between 25 bar and 74 bar, preferably between 45 bar and 70 bar, and more preferably between 50 bar and 60 bar.

[0105] 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.

[0106] 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.

[0107] Then, the epilamated substrate exits the enclosure.

[0108] Optionally, after the pressure in the enclosure has decreased and the epilaminated substrate has left the enclosure, the epilaminated substrate can be thermally treated. For example, the epilamated substrate can be heated in the enclosure to a temperature between 250°C and 90°C, preferably between 30°C and 80°C for a period of time between 1 min and 45 min, preferably between 2 mins and 30 mins. Such heat treatment makes it possible to improve the anchoring of the epilame agent to the surface of the treated substrate.

[0109] The epilaming process according to the invention may further comprise, after bringing the surface of the substrate into contact with the epilame agent, a complementary crosslinking step. Complementary crosslinking is advantageously made possible by the presence of appropriate functional groups of interest provided on the R5 side chains of the U units.

Examples

Example 1

[0110] An epilame agent was produced by statistical copolymerization. The monomer 1H, 1H,2H,2H-perfluorooctyl methacrylate (CAS 2144-53-8; R2 being CH3, glycol) methyl ether methacrylate (CAS 26915-72-0; R1 being CH3, R3 being CH3, α being 2 and Y being C(O)O) and the monomer 2-(methylthio)ethyl methacrylate (CAS 14216-23-0; R4 being CH3, W being C(O)O, A being (CH2)2SCH3), in the presence of the AIBN initiator.

[0111] Figure 1 represents the epilame copolymer obtained, in which R1 is CH3, R2 is CH3, R3 is CH3, R4 is CH3, A is (CH2)2SCH3). The value of q is preferably between 1 and 20 (in the case where this group is present in the copolymer).

[0112] For an average value in the copolymer of β between 8 and 10, for example 9, the m/p/q ratio was 45:45:10. For an average value in the copolymer of β between 18 and 20, for example 19, the m/p/q ratio was 30:60:10.

Example 2

[0113] Three different epilame agents were deposited on the surface of a steel substrate, having previously undergone a surface preparation treatment, using an epilame bath.

The first epilame agent was the copolymer synthesized in Example 1. The epilame bath used was an aqueous epilame bath.

The second epilame agent contains groups of the C6 perfluoroalkyl type, that is to say C6F13 groups, as epilame groups, without the epilame agent containing hydrophilic groups. The hair removal bath used was a hair removal bath containing fluorinated solvents.

[0116] 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. The hair removal bath used was a hair removal bath containing fluorinated solvents.

[0117] In order to evaluate the properties of epilame agents, various tests were carried out.

[0118] As a first test, the surface energy was determined. The procedure, known to those skilled in the art, consists of measuring (using an OCA 15 contact angle measuring device from Dataphysics) 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 by applying the Owens, Wendt, Rabel and Kaelble (OWRK) method.

[0119] The results are presented in Table 1. The surface of the steel substrate without epilame agent, having undergone 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 a value equal (within the measurement error margins) to that of C6F13 type epilame and lower than surface energy measured for the competing epilame. The lower the surface energy, the better the oleophobicity.

[0120] This result demonstrates that the epilame agent of the invention presents itself as a good alternative for the epilame agent of the C6F13 type, while at the same time making it possible to exclude the need for fluorinated solvents.

Table1: the surface energy of different epilame agents

[0121] Epilame of the invention 19.58 Epilame of type C6F13 19.10 Competitor epilame 24.05

Example 3

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

[0123] In order 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 the two oils were deposited and the contact angles were measured using an optical device (Dataphysics OCA 15). In order to evaluate the resistance to watch washing, the substrates were washed three times using a watch wash (amine hydrocarbon solution), followed by measuring the contact angles.

[0124] The target values targeted for each measurement are as follows: – Test oil no. 3 – initial (before washes): 60° – Test oil no. 3 – after 3 washes: 35° – Oil 9010 – initial: 70° – 9010 oil - after 3 washes: 45°

[0125] Figure 2 shows the results on the different substrates for the inventive copolymer. Figure 3 shows the results for the C6F13 type epilame agent, and Figure 4 shows the results for the competing epilame agent.

[0126] It is clear from Figure 4 that for none of the substrates the target values targeted for each oil, before and after 3 washes, are reached. On the other hand, the target values targeted for the 9010 oil are achieved with the copolymer according to the invention and the epilame agent of the C6F13 type on almost all substrates. The target values for oil no. 3 are achieved on the majority of substrates with these two epilame agents (Figures 2 and 3).

Claims (16)

1. Substrate comprising a surface of which at least part is covered 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 bonds covalent by their main chains, where M is N is where R1 and R2, identical or different, are H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, X and Y, identical or different, are spacer arms consisting of a heteroatom or a hydrocarbon chain containing at least one heteroatom, linear or branched, comprising at least one carbon atom, B, identical or different, constitutes a polyether group, L, identical or different, is a halogenated C1-C6 carbon group or a halogenated ether group according to formula (I) where Q is a halogen atom, P, 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, characterized in that the copolymer is soluble in water. 2. Substrate according to claim 1, characterized in that the copolymer is a random copolymer and that the M units and the N units are distributed randomly. 3. Substrate according to claim 1, characterized in that the copolymer is a block copolymer comprising at least one block of M units associated by covalent bonds by their main chains, and at least one block of N units associated by covalent bonds by their main chains, said blocks being connected together by covalent bonds by their main chains in linear sequences. 4. Substrate according to any one of the preceding claims, characterized in that L is a C1-C6 carbon group at least partially fluorinated, preferably completely fluorinated, or an ether group at least partially fluorinated, preferably completely fluorinated. 5. Substrate according to any one of the preceding claims, characterized in that B is a group -((CH2)αO)β-R3, where R3 is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, α is chosen between 1 and 6, preferably between 2 and 3, and β is chosen between 1 and 30, preferably between 2 and 20. 6. Substrate according to any one of the preceding claims, characterized in that X and Y, identical or different, are chosen from the group comprising C1-C20 ester groups, amide groups, and groups derived from styrene, in which X and Y, identical or different, optionally comprise at least one heteroatom. 7. Substrate according to any one of the preceding claims, characterized in that the copolymer, in addition, comprises K units associated with the M and N units by covalent bonds through their main chains, where K is where R4, identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, 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 A, identical or different, constitutes an anchoring group to the substrate. 8. Substrate according to any one of the preceding claims, characterized in that the copolymer, in addition, comprises V units associated with the M and N units by covalent bonds through their main chains, where V is where R5, identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, 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 epilamage bath. 9. Substrate according to claim 8, characterized in that T, identical or different, is a UV absorber group or a fluorophore. 10. Substrate according to any one of the preceding claims, characterized in that its surface, 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. 11. Method for epilaming at least part of a surface of a substrate comprising the steps of: – preparation of an epilame agent comprising at least one water-soluble 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. 12. Epilaming process according to claim 11, characterized in that 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, preferably in which the monomers chosen from the group comprising acrylates, methacrylates, acrylamides, methacrylamides, vinyl and styrenic monomers. 13. Epilamation process according to any one of claims 11 to 12, characterized in that the epilame agent comprises at least one copolymer as defined in claims 8 to 9, its preparation is carried out by preparing a bath of aqueous epilamage containing the epilame agent dissolved in water, and the surface of the substrate is brought into contact with the epilame agent in the aqueous epilamage bath, the process optionally comprising, before contacting, a step for controlling the concentration of epilame agent in the aqueous epilame bath by means of the tracer group and, optionally, a step of readjusting the concentration of epilame agent in the aqueous epilame bath. 14. Epilaming process according to any one of claims 11 to 12, characterized in that the step of bringing the surface of the substrate into contact with the epilame agent comprises the steps of: – placement of the substrate and the epilame agent in an enclosure at ambient pressure, – hermetic closure of the enclosure, – introduction into the hermetically sealed enclosure of 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, – reduction of pressure in the enclosure, and – exit of the epilamated substrate from the enclosure. 15. Use of a copolymer soluble in water and comprising M units and N units, associated by covalent bonds by their main chains, where M is N is where R1 and R2, identical or different, are H, a C1-C10 alkyl group, a C2-C10 alkenyl group, and preferably H or CH3, X and Y, identical or different, are spacer arms consisting of a heteroatom or a hydrocarbon chain containing at least one heteroatom, linear or branched, comprising at least one carbon atom, B, identical or different, constitutes a polyether group, L, identical or different, is a halogenated C1-C6 carbon group or a halogenated ether group according to formula (I) where Q is a halogen atom, P, 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, as an epilame agent of at least part of a surface of a substrate. 16. Timepiece or jewelry item comprising an element comprising a substrate according to any one of claims 1 to 10.