CH710888A2 - Substrate comprising a surface coated with an epilame agent and method of epilamating such a substrate. - Google Patents

Abstract

The invention relates to a substrate comprising a surface at least a portion of which is coated with an epilame agent comprising at least one compound in the form of a random copolymer comprising M units, N units and optionally at least one unit P, covalently linked by their main chains and randomly distributed, wherein R 1, R 2, R 3, which may be identical or different, are H, a C 1 -C 10 alkyl group or a C 1 -C alkenyl group; Y, X, which may be identical or different, are spacer arms consisting of a heteroatom or a hydrocarbon-based chain which may contain at least one heteroatom, comprising at least one carbon atom A, which may be identical or different, constitutes an anchoring group to the substrate, and is selected from the group consisting of thiols, thioethers, thioesters, sulfides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, protected phosphonic acids or no, protected or non-protected phosphonates, amines, ammoniums, nitrogenous heterocycles, carboxylic acids, anhydrides, catechol L, identical or different, is a halogenated C 1 -C 20 carbon group, R 4, which may be identical or different, is H, CH 3 a hydrocarbon chain which may contain at least one heteroatom, comprising at least 2 carbon atoms. The invention also relates to a process for the epilamation of such a substrate, as well as to a timepiece or jewelery piece comprising an element comprising such a substrate.

Description

Field of the invention

[0001] The present invention relates to the field of mechanics and in particular to the field of watchmaking or jewelry. It relates more particularly to a substrate, in particular a substrate of an element of a piece of timepiece or jewelry comprising a surface covered at least partially with an epilame agent. It also relates to a process for epilamating such a substrate, as well as a timepiece or jewelry piece comprising an element comprising such a substrate.

Background of the invention

[0002] There are various methods for modifying the surface finish of a substrate by treatment with 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, epilamage of a surface of a part or of an element is often carried out at 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 piece by forming a hydrophobic and lipophobic surface allowing the lubricant to remain in a predetermined location of the treated surface.

[0003] However, the substances currently used for hair removal have different drawbacks. More specifically, known epilame agents, such as Fixodrop <®> FK / BS from Moebius <®> or the Fluorad ™ range from 3M ™, exhibit poor resistance to watch washes. Patent application US 2012/0 088 099 partially solves this problem by proposing to use an epilame agent carrying a catechol function at the end of the chain, this catechol function being able to bind itself firmly to the surface of the substrates. However, the resistance to watch washings of these epilame agents has not been improved on all substrates, in particular on gold and steel, which are very frequent substrates in the field of watchmaking and jewelry. Thus, the use of known epilame agents is generally limited to certain materials, which requires the user to have at his disposal different types of epilame agents depending on the nature of the surfaces to be treated. A solution for solving this problem is described for example in application WO 2012/085130. This solution consists in using as an epilam composition a mixture of compounds of different nature (thiol and bisphosphonic), the synergistic effect of which promotes the adhesion of epilam to the substrate. However, the synthesis of each of these compounds requires at least four steps, so the synthetic process for the entire epilam composition is long and complex.

Summary of the invention

[0004] The object of the invention is in particular to overcome the various drawbacks of known epilame agents.

[0005] More specifically, an objective of the invention is to provide an epilame agent offering increased resistance to washing compared to known epilame agents.

[0006] The invention also aims to provide a universal epilame agent which can be used for any type of material.

[0007] The invention also aims to provide an epilame agent that is simple to manufacture in a few steps, or even in a single synthetic step.

[0008] To this end, the present invention relates to a substrate comprising a surface of which at least a part is covered with an epilame agent.

[0009] According to the invention, said epilame agent comprises at least one compound in the form of a random copolymer comprising M units, N units and optionally at least one P unit, associated by covalent bonds by their main and distributed chains randomly, where

where R1, R2, R3, identical or different, are H, C1 – C10 alkyl, C1 – C10 alkenyl, and preferably H, CH3 Y, X, identical or different, are spacer arms made up of a heteroatom or of a hydrocarbon chain which may contain at least one heteroatom, linear or branched, comprising at least one carbon atom A, identical or different, constitutes an anchoring group to the substrate, and is chosen from the group comprising thiols, thioethers, thioesters, sulphides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, phosphonic acids, protected or not , phosphonates, protected or not, amines, ammoniums, nitrogenous heterocycles, carboxylic acids, anhydrides, catechol L, identical or different, is a halogenated C1 – C20 carbon group, preferably fluorinated R4, 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.

[0010] Such an epilame agent has improved resistance to washing and has a universal character, allowing its use for any type of material.

The present invention also relates to a method of epilamating at least part of a surface of a substrate comprising the steps of: a) preparing an epilame agent comprising at least one random copolymer as defined herein above b) optionally, preparation of the surface of the substrate c) bringing the surface of the substrate into contact with the epilame agent d) drying.

[0012] The present invention also relates to the use of a random copolymer comprising M units, N units and optionally at least one P unit, associated by covalent bonds by their main chains and distributed randomly, where

where R1, R2, R3, identical or different, are H, C1 – C10 alkyl, C1 – C10 alkenyl, and preferably H, CH3 Y, X, identical or different, are spacer arms made up of a heteroatom or of a hydrocarbon chain which may contain at least one heteroatom, linear or branched, comprising at least one carbon atom A, identical or different, constitutes an anchoring group to the substrate, and is chosen from the group comprising thiols, thioethers, thioesters, sulfides, thioamides, siianols, alkoxysilanes, silane halides, hydroxyls, phosphates, phosphonic acids, whether protected or not , phosphonates, protected or not, amines, ammoniums, nitrogenous heterocycles, carboxylic acids, anhydrides, catechol L, identical or different, is a halogenated C1 – C20 carbon group, preferably fluorinated R4, 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, as epilame agent of at least part of a surface a substrate, in particular intended for watchmaking or jewelry.

[0013] The present invention also relates to a timepiece or piece of jewelry comprising an element comprising a substrate as defined above.

Detailed description of the invention

According to the present invention, a substrate, in particular a substrate of an element of a timepiece or jewelry, comprises a surface at least part of which is covered with an epilame agent, said epilame agent comprising at least one compound in the form of a random copolymer comprising M units, N units and optionally at least one P unit, associated by covalent bonds by their main chains and distributed randomly, where

where R1, R2, R3, identical or different, are H, C1 – C10 alkyl, C1 – C10 alkenyl, and preferably H, CH3 Y, X, identical or different, are spacer arms made up of a heteroatom or of a hydrocarbon chain which may contain at least one heteroatom, linear or branched, comprising at least one carbon atom A, identical or different, constitutes an anchoring group to the substrate, and is chosen from the group comprising thiols, thioethers, thioesters, sulphides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, phosphonic acids, protected or not , phosphonates, protected or not, amines, ammoniums, nitrogenous heterocycles, such as imidazole or pyridine, carboxylic acids, anhydrides, catechol L, identical or different, is a halogenated C1 – C20 carbon group, preferably fluorinated R4, 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.

Preferably, the random copolymer comprises M units, N units and optionally at least one P unit, associated by covalent bonds by their main chains and distributed randomly, where

where R1, R2, R3, identical or different, are H, C1 – C10 alkyl, C1 – C10 alkenyl, and preferably H, CH3, Y, X, identical or different, are spacer arms made up of a heteroatom or of a hydrocarbon chain which may contain at least one heteroatom, linear or branched, comprising at least one carbon atom A, identical or different, constitutes an anchoring group to the substrate, and is chosen from the group comprising thiols, thioethers, thioesters, sulphides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, phosphonic acids, protected or not , phosphonates protected or not, amines, ammoniums, nitrogenous heterocyciae, such as imidazole or pyridine, carboxylic acids, anhydrides, catechol L, identical or different, is a halogenated C1 – C20 carbon group, preferably fluorinated R4, 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, with the exception of the copolymer:

Preferably, the random copolymer only comprises M, N and optionally P.

[0017] The M, N and P units are statistically linked to each other by their main chain so that the random copolymer can be written in the form:

Advantageously, the Y, X groups, which are identical or different, are chosen from the group comprising ester groups in C1 – C20, 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.

[0019] The functional groups of interest A are able to react 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, groups A can also be provided at the end of the copolymer.

[0020] Advantageously, the copolymer comprises at least two different A groups.

[0021] The functional groups of L interest are responsible for the epilame effect. They comprise at least one halogen atom, preferably a fluorine atom. Preferably, L is a C2 – C20, preferably C4 – C10, and more preferably C6 – C9, carbon group. L is partially or totally halogenated. Advantageously, L is an at least partially fluorinated, and preferably fully fluorinated, group. L can also have a hydrogen atom on the terminal group.

[0022] The functional groups of interest R4 of the P units are used to modify the properties of the epilame agent and / or provide other functions. For example, R4 can be an alkyl chain used to modify the contact angle obtained or a chain capable of constituting crosslinking points during an additional crosslinking step (step e).

Preferably, the random copolymer comprises between 0.1% and 50%, preferably between 5% and 30%, and more preferably between 5% and 20% of M units, between 1% and 99.9%, preferably between 50% and 99.9%, and more preferably between 80% and 95% of N units, and between 0% and 50%, preferably between 0% and 30%, and more preferably between 0% and 10% of P units , the percentages being expressed relative to the total number of units (x + y + z).

[0024] Advantageously, the random copolymer comprises between 10 and 350 units (x + y + z).

[0025] In a particularly advantageous manner, the units M, N, P are chosen to carry several groups A of different nature, several groups L, preferably of the same nature, and optionally one or more groups R4 which may be identical or of different nature, so as to refine and improve the properties of the epilame agent, in order to obtain more specifically an epilame agent that is universal and exhibits improved affinity with the substrate.

Preferably, the surface of the substrate, at least a part of which is covered with the epilame agent is made of a material chosen from the group comprising metals, metal oxides, doped or not, polymers, sapphire, ruby, silicon, silicon oxides, silicon nitrides, silicon carbides, DLC (Diamond Like Carbon), and their alloys.

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

The present invention also relates to a method of epilamating at least part of a surface of a substrate comprising the steps of: a) preparing an epilame agent comprising at least one random copolymer as defined herein - above b) optionally, preparation of the surface of the substrate, in particular by cleaning according to standard horological methods, c) bringing the surface of the substrate into contact with the epilame agent d) drying.

Preferably, the preparation of the epilame agent is carried out by random copolymerization of monomers capable of forming M units with monomers capable of forming N units and optionally with monomers capable of forming at least one P unit.

[0030] Statistical polymerization techniques are well known to those skilled in the art and do not require a detailed description. A particularly suitable mode of polymerization is free radical copolymerization, in solution or in emulsion.

According to a first variant, the random copolymer can be obtained in a single step by copolymerization, preferably radical, of monomers carrying the side chains Y – A with monomers carrying the side chains X – L and optionally monomers carrying the side chains. R4 side chains.

According to another variant, the random copolymer can be obtained by copolymerization, preferably radical, of monomers bearing the appropriate Y side chains with monomers bearing the appropriate X side chains and optionally monomers bearing side chains intended to carry R4 , then the side chains are modified, for example by “click chemistry”, to introduce therein the functional groups of interest A, L and the groups R4.

Preferably, the monomers are chosen from the group comprising acrylate, methacrylate, acrylamide, methacrylamide, vinyl, diene, styrene and olefinic monomers.

The acrylate, methacrylate, acrylamide, methacrylamide, vinyl and styrenic monomers are particularly preferred. These products are known and for the most part available on the market or accessible in a synthetic step.

Particularly preferred monomers are:

[0036] Thus, the copolymer used as epilame agent can be easily obtained in a single step or a limited number of steps from commercial products.

One of the copolymers preferably used in the present invention has the following structure (I)

[0038] More particularly, a copolymer preferably used in the present invention has the following structure (II):

[0039] The copolymers used in the invention can be obtained in the form of powder or viscous liquid. They can then be dissolved in a fluorinated solvent, such as perfluorinated or fluorinated hydrocarbons, perfiuoropolyethers, hydrofluoroolefins, hydrofluoroethers, at concentrations preferably between 50 mg / L and 250 mg / L, in order to obtain an epilame agent solution, which will be used for the treatment of surfaces to be epilamated.

According to the variants, the epilamage process according to the invention may further comprise, after step c), a step e) of additional crosslinking, made possible in particular by the presence of the appropriate functional groups of interest provided. on the R4 side chains of the P units.

[0041] The substrate according to the invention has a surface covered with an epilame agent which is simple and economical to synthesize, exhibiting an affinity with any type of substrate and an improved resistance to washing compared to known epilame agents. An element or part having a substrate in accordance with the invention can be used in all types of applications in the mechanical field, and more particularly in precision mechanics, and in particular watchmaking and jewelry.

[0042] The following examples illustrate the present invention without, however, limiting its scope.

Synthesis of 3-methacryloxopropyl methyl thioether:

In a three-necked flask under magnetic stirring placed under nitrogen are added thiomethylpropanol (4.05 mL), dichloromethane (100 mL) and triethylamine (8.2 mL). The solution is cooled in an ice bath and then methacrylate chloride (3.8 mL) is added dropwise over 10 min. The reaction mixture is stirred for 2 h at 0 ° C. then at room temperature overnight. 70 ml of water are added then the reaction mixture is transferred to a separating funnel. The organic phase and the aqueous phase are separated. The organic phase is washed with an HCl solution (pH = 4) until pH = 7 is reached and then dried over Na2SO4. The solvent is then removed on a rotary evaporator to yield the expected product with a yield of 97%.

<1> H NMR (CDCl3, 500 MHz): chemical shift (ppm): 6.10 (s, 1 H), 5.56 (s, 1 H), 4.24 (t, 2 H), 2.58 (t, 2 H), 2.11 (s, 3H), 1.99 (m, 2H), 1.94 (s, 3H)

Example 1

An epilame agent is synthesized in the form of a random copolymer by free radical polymerization of: 3-acryloxopropyl methyldimethoxysilane 1 H, 1 H, 2 H, 2 H-Perfluorodecylacrylate 3-methacryloxopropyl methyl thioether prepared as indicated above according to the following procedure: in a Schlenk tube containing cyclohexanone (2.5 mL) degassed beforehand with nitrogen, are added 3-acryloxopropyl methyldimethoxysilane (189 μL) and 3-methacryloxopropyl methyl thioether (159 μL) then 1 H, 1 H, 2 H, 2 H-Perfluorodecylacrylate (2.3 mL). The reaction medium is bubbled 5 min with nitrogen and then 0.8 mL of Novec ™ hydrofluoroether HFE-7200 (3M ™) previously bubbled with nitrogen are added. 0.5 mL of a 0.228 mol / L azobisisobutyronitrile (AIBN) solution is added. The reaction medium is stirred and heated at 80 ° C. for 3 h. The polymer is coagulated in methanol and then rinsed with 3 * 50mL. The polymer is obtained in the form of a white powder (yield = 90%).

The following random copolymer is obtained:

Example 2

An epilame agent is synthesized in the form of a crosslinked random copolymer by free radical polymerization of: 3-acryloxopropyl methyldimethoxysilane 1H, 1H, 2H, 2H-Perfluorodecylacrylate 3-methacryloxopropyl methyl thioether 1,6-Hexanediol dimethacrylate according to the following procedure: in a Schlenk tube containing cyclohexanone (2.5 mL) degassed beforehand with nitrogen, are added 3-acryloxopropyl methyldimethoxysilane (189 µl_) and 3-methacryloxopropyl methyl thioether (159µ.L), 1,6-Hexanediol dimethacrylate (12 μl) then 1 H, 1 H, 2 H, 2 H-Perfluorodecylacrylate (2.3 mL). The reaction medium is bubbled 5 min with nitrogen then 0.8 ml of Novec ™ HFE-7200 previously bubbled with nitrogen are added. 0.5mL of a 0.228 mol / L solution of AIBN is added. The reaction medium is stirred and heated at 80 ° C. for 3 h. The polymer is coagulated in methanol and then rinsed with 3 * 50 mL. The polymer is obtained in the form of a white powder (yield = 97%).

The following crosslinked random copolymer is obtained:

In this copolymer, the R4 side chain of the P units is crosslinked with the side chain of another copolymer.

Example 3

An epilame agent is synthesized in the form of a post-crosslinkable random copolymer by free radical polymerization of: 3-acryloxopropyl methyldimethoxysilane 1 H, 1 H, 2 H, 2 H-Perfluorodecylacrylate 3-methacryloxopropyl methyl thioether 2-Cinnamoyloxyethyl acrylate (post-crosslinkable monomer) according to the following procedure: in a Schlenk tube containing cyclohexanone (2.5 mL) degassed beforehand with nitrogen, are added 3-acryloxopropyi methyldimethoxysilane (189 μL) and 3-methacryloxopropyl methyl thioether (159 μL), 2-Cinnamoyloxyethyl acrylate (92 mg) then 1H, 1H, 2H, 2H-Perfluorodecylacrylate (2. 2 mL). The reaction medium is bubbled 5 min with nitrogen and then 0.8 mL of Novec ™ HFE-7200 previously bubbled with nitrogen are added. 0.5 mL of a 0.228 mol / L solution of AIBN is added. The reaction medium is stirred and heated at 80 ° C. for 3 h. The polymer is coagulated in methanol and then washed with 3 * 50 mL. The polymer is obtained in the form of a white powder (yield = 90%).

The following post-crosslinkable random copolymer is obtained:

In this copolymer, the side chain R4 can be UV crosslinked just after synthesis or after deposition on the substrate.

Example 4

An epilame agent is synthesized in the form of a random copolymer by free radical polymerization of: 3-acryloxopropyl methyltrimethoxysilane 1 H, 1 H, 2 H, 2 H-Perfluorodecylacrylate (dimethoxyphosphoryl) methyl 2-methylacrylate 2-thioethyl methacrylamide (synthesized according to the procedure described in the publication: Synthesis and characterization of a high selective mercury (ll) -imprinted polymer using novel aminothiol monomer, Talanta, 101, 261–266; 2012) according to the following procedure: in a Schlenk tube containing cyclohexanone (2.5 mL) degassed beforehand with nitrogen, are added 3-acryloxopropyl methyltrimethoxysilane (378 μL) and 2-thioethyl methacrylamide (132 μL) then 1 H, 1 H, 2 H, 2 H-Perfluorodecylacrylate (2.3ml_). The reaction medium is bubbled 5 min with nitrogen then 0.8 ml of Novec ™ HFE-7200 previously bubbled with nitrogen are added. 0.5 mL of a 0.228 mol / L azobisisobutyronitrile (AIBN) solution is added. The reaction medium is stirred and heated at 80 ° C. for 3 h. The polymer is coagulated in methanol and then rinsed with 3 * 50 mL. The polymer is obtained in the form of a white powder (yield = 90%).

The following random copolymer is obtained:

Example 5

An epilame agent is synthesized in the form of a random copolymer by free radical polymerization of: 3-acryloxopropyl methyldimethoxysilane 1 H, 1 H, 2 H, 2 H-Perfluorooctylacrylate 3-acryloxopropyl methyl thioether (obtained according to the procedure described in the literature: Preparation of biomimetic polymer hydrogel materials for contact lenses Bertozzi, Carolyn et al. US 6 552 103) according to the following procedure: in a Schlenk tube containing cyclohexanone (2 mL) degassed beforehand with nitrogen, are added 3-acryloxopropyl methyldimethoxysilane (148 μL) and 3-acryloxopropyl methylthioether (108 μl) then 1 H, 1 H, 2 H, 2 H-Perfluorooctylacrylate (2.1 mL). The reaction medium is bubbled 5 min with nitrogen and then 0.8 ml of hydrofluoroether (Novec HFE-7200) previously bubbled with nitrogen are added. 0.5 mL of a 0.228 mol / L azobisisobutyronitrile (AIBN) solution is added. The reaction medium is stirred and heated at 80 ° C. for 3 h. The polymer is coagulated in methanol and then rinsed with 3 * 50 mL. The polymer is obtained in the form of a translucent gel (yield = 90%).

The following random copolymer is obtained:

Example 6: Resistance to washing

Procedures used

Preparation of substrates

Before the epilame treatment, substrates of different types are cleaned by standard watchmaking processes. More specifically, the parts are cleaned with a solution of Rubisol in the presence of ultrasound, rinsed 3 times with isopropyl alcohol, and then dried in hot air.

Epilame treatment of substrates

The substrates are epilamated by immersion (approximately 5 min) in a solution of the epilame agent (solvent: Vertrel <®> Suprion ™ from DuPont ™ at 250 mg / L) then drying in hot air.

Resistance to washing

The resistance to washing of epilame agents is evaluated after 3 successive washes (standard watch wash with a solution of Rubisol) of the epilamated parts.

Contact angles

The effectiveness of the epilame agent is evaluated by depositing drops of 2 lubricants: MOEBIUS Testôl 3 and 9010 oil. For each lubricant and each epilame agent, the contact angles between the substrates and the lubricants were measured. on a Dataphysics device of the OCA type.

Results

[0061] The various substrates are epilamated with either the epilame agent of Example 1 or with the epilame agent of Example 4. The substrates are then washed with 3 clock washes.

For comparison, different substrates are epilamated: either with Fixodrop <®> FK / BS from Moebius <®> (among the most widely used epilames on the market) or with the epilame agent M51 below, described in publication WO 2014/009 058 followed by 3 watch washes.

[0063]

Epilame agent M51 is known to be one of the most resistant epilame agents to watch washings.

[0064] Drops of Testôl 3 oil, respectively 9010 oil, are deposited on each epiiamé substrate and the contact angles between the substrates and the lubricants are measured.

The results are shown in the tables below which report the values of the contact angles measured:

Table 1

[0066] Contact angles measured with MOEBIUS 9010 oil

Table 2

[0067] Contact angles measured with MOEBIUS Testöl 3 oil

Conclusion

The above results show that the contact angles obtained after three clock washings with the two oils (Testöl 3 and 9010) are much higher for the epilamated substrates according to the invention compared to the epilame substrate by a known epilame agent . The epilame effect after three watch washes is therefore much greater with the epilamated substrates according to the present invention. This demonstrates that the epilamated substrates according to the invention exhibit better resistance to washing, whatever their nature.

Claims (14)

1. Substrate comprising a surface of which at least a part is covered with an epilame agent, characterized in that said epilame agent comprises at least one compound in the form of a random copolymer comprising M units, N units and optionally in minus one unit P, associated by covalent bonds by their main chains and distributed in a random manner, where where R1, R2, R3, identical or different, are H, C1 – C10 alkyl, C1 – C10 alkenyl, and preferably H, CH3 Y, X, identical or different, are spacer arms made up of a heteroatom or of a hydrocarbon chain which may contain at least one heteroatom, linear or branched, comprising at least one carbon atom A, identical or different, constitutes an anchoring group to the substrate, and is chosen from the group comprising thiols, thioethers, thioesters, sulphides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, phosphonic acids, protected or not , phosphonates, protected or not, amines, ammoniums, nitrogenous heterocycles, carboxylic acids, anhydrides, catechol L, identical or different, is a halogenated C1 – C20 carbon group, preferably fluorinated R4, 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. 2. Substrate according to claim 1, characterized in that Y, X, identical or different, are chosen from the group comprising ester groups in C1 – C20, preferably C2 – C10, amide groups, and groups derived from styrene. 3. Substrate according to one of the preceding claims, characterized in that the copolymer comprises at least two different A groups. 4. Substrate according to one of the preceding claims, characterized in that L is a carbon group in C2 – C20, preferably C4 – C10. 5. Substrate according to one of the preceding claims, characterized in that L is an at least partially fluorinated, preferably fully fluorinated, group. 6. Substrate according to one of the preceding claims, characterized in that the random copolymer comprises between 0.1% and 50%, preferably between 5% and 30% of M units, between 1% and 99.9%, preferably between 50 % and 99.9% of N units, and between 0% and 50%, preferably between 0% and 30% of P units. 7. Substrate according to one of the preceding claims, characterized in that the random copolymer comprises between 10 and 350 units. 8. Substrate according to one of the preceding claims, characterized in that its surface of which at least a part 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, DLC (Diamond Like Carbon), and their alloys. 9. A method of epilamating at least part of a surface of a substrate comprising the steps of: a) preparation of an epilame agent comprising at least one random copolymer as defined in claims 1 to 7 b) optionally, preparation of the substrate surface c) contacting the surface of the substrate with the epilame agent d) drying. 10. A method of epilamage according to claim 9, characterized in that the preparation of the epilame agent is carried out by random copolymerization of monomers capable of forming M units with monomers capable of forming N units and optionally with suitable monomers. to form at least one P. 11. A hair removal process according to one of claims 9 to 10, characterized in that it further comprises, after step c), a step e) of additional crosslinking. 12. A method of depilamation according to one of claims 9 to 11, characterized in that the monomers are chosen from the group comprising acrylate, methacrylate, acrylamide, methacrylamide, vinyl and styrene monomers. 13. Use of a random copolymer comprising M units, N units and optionally at least one P unit, associated by covalent bonds by their main chains and distributed randomly, where where R1, R2, R3, identical or different, are H, C1 – C10 alkyl, C1 – C10 alkenyl, and preferably H, CH3 Y, X, identical or different, are spacer arms made up of a heteroatom or of a hydrocarbon chain which may contain at least one heteroatom, linear or branched, comprising at least one carbon atom A, identical or different, constitutes an anchoring group to the substrate, and is chosen from the group comprising thiols, thioethers, thioesters, sulphides, thioamides, silanols, alkoxysilanes, silane halides, hydroxyls, phosphates, phosphonic acids, protected or not , phosphonates, protected or not, amines, ammoniums, nitrogenous heterocycles, carboxylic acids, anhydrides, catechol L, identical or different, is a halogenated C1 – C20 carbon group, preferably fluorinated R4, 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, as epilame agent of at least part of a surface of a substrate. 14. Piece of timepiece or jewelry comprising an element comprising a substrate according to any one of claims 1 to 8.