CH713789A2 - Epilamating agent and epilamination process using such an agent - Google Patents

Abstract

The invention relates to an epilamating agent comprising at least one compound comprising at least hydrophobic and oleophobic groups designed to confer epilame properties on said compound, and at least one hydrophilic group designed to make said compound soluble in an aqueous medium, said hydrophilic group being bound to the compound by at least one cleavable group. The invention also relates to a process for the epilamination of a substrate comprising the preparation of an aqueous epilamation bath by solubilization of such an epilamating agent, the bringing of the substrate into contact with the epilamating agent in the bath epilamating, separating the hydrophilic group from the epilamating agent by cleavage, rinsing the substrate to remove hydrophilic residues from the hydrophilic group, and drying.

Description

Description

FIELD OF THE INVENTION [0001] The present invention relates to the field of mechanics and in particular to the field of watchmaking or jewelery. It relates more particularly to an epilamating agent, a copolymer, as well as a substrate, in particular a substrate of an element of a timepiece or jewelery including a surface covered at least partially with an epilame derived from such an epilamating agent or such a copolymer. It also relates to a process for epilamating such a substrate, as well as a timepiece or jewelery including an element comprising such a substrate.

BACKGROUND OF THE INVENTION [0002] There are various methods for modifying the surface condition of a substrate by treatment with a suitable agent so as to specifically improve certain surface properties. For example, in the field of mechanics, and in particular in the field of watchmaking, but also in the field of jewelery, the epilamization of a surface of a part or an element is often performed at using an epilamating agent to control and reduce the surface energy of said surface during its use. More particularly, an epilame is intended to prevent the spread of oils or lubricants on the elements of a timepiece or jewelery by forming a hydrophobic and lipophobic (or oleophobic) surface allowing the lubricant to remain in one place predetermined of the treated surface.

The standard epilamization process is a dip coating process. It involves dipping the timepieces in an epilamage bath, that is to say a solution of the epilamating agent in a solvent. The permanent and effective depilating agents currently used for epilamination are at least partially fluorinated. As a result, the molecules that compose them are not or only slightly soluble in solvents other than fluorinated solvents. The epilamating baths must therefore be based on fluorinated solvent, and therefore, are not ecological. They may also require the use of closed equipment with vapor recovery and reprocessing, which generates significant costs.

To solve this problem, a proposed solution has been to develop epilamating agents comprising more weakly fluorinated molecules and which can be solubilized in an organic solvent, such as isopropyl alcohol. However, the epilame deposited has a resistance to washing and an epilame effect that does not meet the requirements of watchmaking. In addition, the organic solvents used also have drawbacks, such as flammability and toxicity. SUMMARY OF THE INVENTION [0005] One of the objectives of the invention is to overcome the various disadvantages of known epilamating agents and epilamization processes.

More specifically, an object of the invention is to provide an epilamating agent for an ecological epilamization process, using an aqueous epilamating bath.

For this purpose, the present invention relates to an epilamiding agent comprising at least one compound comprising at least hydrophobic and oleophobic groups arranged to confer epilamous properties to said compound, and at least one hydrophilic group arranged to make said soluble compound. in an aqueous medium, said hydrophilic group being bonded to the compound by at least one cleavable group.

The present invention also relates to a copolymer comprising M units, N units, and optionally at least one P unit, associated by covalent bonds with their main chains, where

wherein R 1, R 2, R 3, which are identical or different, are H, C 1 -C 10 alkyl, C 1 -C 10 alkenyl and preferably H, CH; W, 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, linear or branched, comprising at least one carbon atom Y, which is identical or different, is a grouping comprising at least one cleavable group; A, identical or different, is a hydrophilic group arranged to render said copolymer soluble in aqueous medium; L, identical or different, is a halogenated C 1 -C 20 carbon-based group, preferably fluorinated; Q, identical or different, is H, CH3, a hydrocarbon chain, preferably different from A, which may contain at least one heteroatom, linear or branched, saturated or unsaturated, comprising at least one carbon atom.

The present invention also relates to a block copolymer comprising at least one block of N units and optionally at least one P unit, associated by covalent bonds with their main chains, and at least one block comprising at least one hydrophilic group arranged to render said copolymer soluble in an aqueous medium, said blocks being linked together by covalent bonds by at least one cleavable group Y, where N, P, and Y are as defined above, [0010] particularly preferably, the epilamating agent according to the invention comprises at least one compound consisting of one of the copolymers defined above.

Such an epilamating agent allows the use of an aqueous epilamisation bath to obtain an economical and ecological epilamization process, while allowing to obtain a high-performance and permanent epilame effect.

The present invention also relates to an epilamization bath comprising at least 50% by volume of water and an epilamating agent as defined above.

The present invention also relates to the use of a compound comprising at least hydrophobic and oleophobic groups arranged to provide said compound with epilamous properties, and at least one hydrophilic group arranged to render said compound soluble in an aqueous medium, said grouping hydrophilic being bound to the compound by at least one cleavable group, as an epilamating agent.

The present invention also relates to the use of a copolymer as defined above as an epilamating agent.

The present invention also relates to a process for epilamating at least a portion of a surface of a substrate comprising the steps of: a) preparing an epilamation bath by solubilization of at least one agent of epilamization as defined above or comprising at least one copolymer as defined above in a solution containing at least 50% by volume of water b) optionally, preparation of the surface of the substrate c) brought into contact with the surface of the substrate with the epilamating agent in the epilamination bath d) optionally, drying e) separation of the hydrophilic group from the epilamating agent by cleavage f) rinsing of the surface of the substrate g) drying.

The present invention also relates to a substrate comprising a surface at least a portion of which is covered with an epilame, characterized in that said epilame has been obtained by cleaving an epilamating agent as defined above or comprising at least one copolymer as defined above, said epilame comprising at least one compound comprising at least hydrophobic and oleophobic groups and at least one residue of a cleavable group which has been used to bind at least one hydrophilic group to said compound .

The present invention also relates to a timepiece or jewelery comprising an element comprising a substrate as defined above.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, there is described an epilamating agent comprising at least one compound comprising at least hydrophobic and oleophobic groups arranged to confer epilamous properties on said compound, and at least one group hydrophilic composition arranged to render said compound soluble in aqueous medium, said hydrophilic group being covalently bonded to the compound by at least one cleavable group.

Advantageously, the hydrophobic and oleophobic groups, which are identical or different, comprise a halogenated, preferably fluorinated C1-C20 carbon group.

The hydrophilic groups used in the invention are capable of making bonds (hydrogen, ionic) with water molecules. They are chosen to be highly polar and hydrophilic in order to be able to solubilize in an aqueous solution, preferably water, the compound and its hydrophobic and oleophobic groups with an epilame effect. The number and / or the size of the hydrophilic groups are chosen so as to temporarily mask the hydrophobic effect of said hydrophobic and oleophobic groups with an epilame effect. Thus, the epilamating agent according to the invention can be used in the form of an aqueous epilating bath, perfectly ecological, making it possible to deposit an epilamating agent by means of an ecological epilamization process.

Preferably, the hydrophilic group is chosen from the group comprising a group derived from a glycol ether, a group derived from an amine, an alcohol, a carboxylic acid, a sulphonic acid, a phosphonic acid, a carboxylate salt, a sulfonate salt, a phosphonate salt.

In a particularly preferred manner, the hydrophilic group used in the invention is a group derived from a glycol ether which is in the form of a group derived from a polyether, preferably a polyethylene glycol or a polyether glycol. polypropylene glycol, or a group derived from an amine in the form of a group derived from a polyamine.

Once the epilayer is deposited on the surface of a substrate, the hydrophilic group useful for solubilization in an aqueous medium must now be removed from the compound and removed from the surface of the substrate so that the compound remaining in surface has the desired epilam effect, thanks to its hydrophobic and oleophobic groups with epilame effect.

For this purpose, the hydrophilic group is bonded to the compound by a cleavable chemical bond, by means of a cleavable group covalently bonding said hydrophilic group to the compound.

Preferably, the cleavable group is a cleavable group by at least one of the treatments chosen from the group comprising a UV treatment, a heat treatment, a mechanical stimulus treatment, an enzyme treatment, and a trigger treatment. chemical. The different treatments for separating the hydrophilic group from the epilamating agent can be applied individually, or simultaneously or in series, depending on the nature of the cleavable group to be separated from the rest of the compound carrying the hydrophobic and oleophobic groups. with the hydrophilic group. Preferably, the cleavable group is selected from the group consisting of a UV-cleavable group, a heat-cleavable group, a cleavable group by a mechanical stimulus, an enzyme-cleavable group, and a cleavable group by a chemical trigger.

In a particularly preferred manner, the cleavable group is chosen from the group comprising a group derived from a nitrobenzyl ester which is cleavable by UV, such as

an adduct of a reaction of Diels Aider, cleavable by heat treatment, such as

a group cleavable by a mechanical stimulus (for example ultrasound), such as

a group cleavable by an enzyme, for example an esterase, and a group comprising a dithio function, cleavable by a chemical trigger, such as

where R is the compound with its hydrophobic and oleophobic groups with epilam effect and R 'is the hydrophilic group.

[0027] In a particularly preferred manner, the cleavable group is a group derived from a nitrobenzyl ester.

According to the embodiments, the cleavable group with the associated hydrophilic group may form a linear or branched structure with the compound, and the hydrophobic and oleophobic groups may also form a linear or branched structure with the compound, the various combinations being possible. Thus, for example, the hydrophobic and oleophobic groups and the hydrophilic groups bonded to the compound by a cleavable group respectively form side chains on the carbon skeleton of the compound, distributed statistically or in block, or the hydrophobic and oleophobic groups form chains. laterally on the carbon skeleton of the compound and the hydrophilic groups form a linear structure and are linked by a cleavable group to the compound, or the hydrophobic and oleophobic groups form side chains on the carbon skeleton of the compound, and the hydrophilic groups form side chains. on a carbon skeleton bound to the compound by a cleavable group.

The present invention also relates to a copolymer comprising M units, N units, and optionally at least one P unit, associated by covalent bonds by their main chains, where

wherein FL, R2, R3, which may be identical or different, are H, C1-C10 alkyl, C1-C10 alkenyl, and preferably H, CH3; W, 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, linear or branched, comprising at least one carbon atom; Y, identical or different, is a group comprising at least one cleavable group; A, identical or different, is a hydrophilic group arranged to render said copolymer soluble in aqueous medium; L, identical or different, is a halogenated, preferably fluorinated C 1 -C 20 carbon group; Q, identical or different, is H, CH3, a hydrocarbon chain, preferably different from A, which may contain at least one heteroatom, linear or branched, saturated or unsaturated, comprising at least one carbon atom.

Such a copolymer may be used to form the epilayer agent compound as defined above.

[0031] Preferably, the copolymer consists only of M and N units and optionally R units. Preferably, the copolymer consists only of Μ, N and P units.

The copolymer of the invention may be a random copolymer in which the units Μ, N and P are statistically connected together by their main chains, that is to say distributed randomly, so that the copolymer statistic can be written as (I):

The copolymer of the invention may also be 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 optionally comprising at least one associated P unit. by covalent bonds by their main chains, said blocks being connected together by covalent bonds by their main chains in linear sequences.

The block copolymer can be written in the form (II):

[0035] Preferably, the block copolymer comprises a single block of units M and a single block of units N comprising op-tionally at least one unit R

Preferably, the M units are distributed by random copolymerization to form a single block consisting of M units.

The units P can be distributed within the block composed of the N units, for example by random copolymerization of P units with the N units, the whole forming a single block preferably consisting mainly of N units and similar to a block of units N.

The units P may also be in the form of a third block, the unit block P being preferably connected to the unit block N, itself connected to the block of units M, by covalent bonds by their main chains in linear sequences. The block copolymer can be written in the form:

In a preferred manner, the group A is a hydrophilic group chosen from the group comprising a group derived from a glycol ether, preferably in the form of a group derived from a polyether, preferably a group derived from a polyethylene glycol (PEG) or a polypropylene glycol (PPG), a group derived from an amine, preferably in the form of a group derived from a polyamine, a group derived from a an alcohol, a carboxylic acid, a sulfonic acid, a phosphonic acid, a carboxylate salt, a sulfonate salt and a phosphonate salt. The group derived from a polyether or a polyamine preferably comprises between 2 and 100 units, more preferably between 5 and 30 units. In a particularly preferred manner, A is a group derived from a polyethylene glycol (PEG) or a polypropylene glycol (PPG), preferably comprising between 2 and 100 units, more preferably between 5 and 30 units.

The present invention also relates to a block copolymer comprising at least one block of units N optionally comprising at least one P unit, associated by covalent bonds with their main chains, and at least one block comprising at least one hydrophilic group arranged to rendering said copolymer soluble in an aqueous medium, said blocks being linked together by covalent bonds with at least one cleavable group Y, where N, P, and Y are as defined above.

Such a copolymer may be used to constitute the epilamating agent compound as defined above.

According to an alternative embodiment, the block comprising at least one hydrophilic group is a group A 'chosen from the group comprising at least one group derived from a glycol ether, preferably in the form of a grouping. derived from a polyether, preferably a group derived from a polyethylene glycol (PEG) or a polypropylene glycol (PPG), and a group derived from an amine, preferably in the form of a group derived a polyamine, the block copolymer being able to be written in the form (III):

Preferably, the hydrophilic group A 'comprises between 1 and 200 units, more preferably between 5 and 100 units, and even more preferably between 10 and 50 units. In a particularly preferred manner, A 'is a group derived from a glycol ether preferably comprising between 1 and 200 units of ethylene or propylene glycol. Preferably, A 'is a group derived from a polyethylene glycol (PEG) or a polypropylene glycol (PPG), preferably comprising between 2 and 200 units of ethylene or propylene glycol, more preferably between 5 and 100 units, and even more preferably between 10 and 50 units.

According to another variant embodiment, the block comprising at least one hydrophilic group comprises G units associated by covalent bonds by their main chains,

wherein R4, identical or different, is H, (C1-C6) alkyl, (C1-C6) alkenyl, and preferably H, CH3; Z, identical or different, is a spacer arm consisting of a heteroatom or a hydrocarbon chain which may contain at least one heteroatom, linear or branched, comprising at least one carbon atom A is as defined above.

Such a block copolymer can be written in the form (IV):

The group A is as defined above, so that, for example, the block comprising at least one hydrophilic group comprising G units is a group derived from a functional poly ((meth) acrylate po-lyether preferably poly ((meth) acrylate functional PEG or PPG), functional poly ((meth) acrylate polyamine), functional poly ((meth) acrylate amine), poly ((meth) acrylate functional alcohol), poly carboxylic acid functional (meth) acrylate), sulfonic acid functional poly ((meth) acrylate), functional phosphonic acid poly ((meth) acrylate), poly ((meth) acrylate functional carboxylate), poly ((meth) functional acrylate sulfonate), functional poly ((meth) acrylate phosphonate), poly (styrene functional PEG or PPG), poly (styrene functional phosphonate), poly (styrene functional sulfonate), depoly (functional styrene phosphonic acid) or poly (styrene functional sulphonic acid). The term (meth) acrylate means acrylate or methacrylate.

Preferably, the block comprising at least one hydrophilic group comprising G units is a group derived from a poly ((meth) acrylate functional PEG or PPG) or from a poly (functional styrene PEG or PPG), [ The number of units z is at least two, preferably between 5 and 200 units, and more preferably between 10 and 100.

The block A 'and the block comprising the units G may be used with the unit block N optionally comprising at least one unit P to form a triblock copolymer.

For all of the copolymers defined above, the groups W, X, Z, which are identical or different, are advantageously chosen from the group comprising C 1 -C 20 ester groups, preferably from C 2 -C 10, more preferably C 2 -C 6, and even more preferably C 2 -C 5, preferably alkyl ester groups, preferably linear, amide groups, and groups derived from styrene.

Preferably, Y is a group comprising a group which can be cleaved by at least one of the treatments chosen from the group comprising a UV treatment, a heat treatment, a mechanical stimulus treatment, an enzyme treatment, and a treatment with chemical trigger. The different treatments for separating the hydrophilic group from the epilamating agent can be applied individually, or simultaneously or in series, depending on the nature of the cleavable group to be separated from the rest of the compound carrying the hydrophobic and oleophobic groups. with the hydrophilic group. Particularly preferably, Y is a group comprising a cleavable group selected from the group consisting of a UV cleavable group, a heat-cleavable group, a cleavable group by a mechanical stimulus, an enzyme-cleavable group, and a cleavable group. cleavable group by a chemical trigger. Preferably, Y is a group comprising a cleavable group chosen from the group comprising a group derived from a nitrobenzyl ester, an adduct of a Diels Aider reaction, a cleavable group, for example by ultrasound, a cleavable group, for example by a esterase and a group comprising a dithio function, as already defined above relative to the epilamating agent according to the invention. Depending on the cleavable group, the separation of the hydrophilic group from the rest of the compound carrying the hydrophobic and oleophobic groups is done by preferably breaking the covalent bond connecting the cleavable group to said compound carrying the hydrophobic and oleophobic groups, so that only remains on the The compound carrying the hydrophobic and oleophobic groups has the most neutral residue possible with respect to epilamation properties, the bulk of the molecule of the cleavable group leaving with the hydrophilic group.

The functional groups of interest A or A 'are capable of making bonds (hydrogen, ionic) with water molecules. They are chosen to be highly polar and hydrophilic in order to be able to solubilize in an aqueous solution, preferably water, the copolymer and its L groups. The number and / or the size of the groups A and A 'are chosen so as to be able to mask, temporarily , the hydrophobic effect of said groups L.

The functional groups of interest L are responsible for the epilame effect and correspond to the hydrophobic and oleophobic groups with epilam effect of the epilamating agent of the invention described above, they comprise at least one atom of halogen, preferably a fluorine atom. In a preferred manner, L is a carbon group, ie an alkyl chain, which may be cyclic, preferably without heteroatom, in C 2 -C 20, preferably in C 4 -C 10, and more preferably in C 6 -C 9. L is partially or totally halogenated. Advantageously, L is an at least partially fluorinated group, and preferably a totally fluorinated group. L may also include a hydrogen atom on the terminal group. L is preferably a perfluorinated alkyl chain.

The functional groups of interest 0 P units are used to modify the properties of the copolymer or the epilamage agent and / or provide other functions. Advantageously, the copolymer comprises at least two different Q groups.

For example, the functional groups of interest Q are able to react with the surface of the substrate to be epilated, so as to form anchoring groups of the epilamating agent on the surface of a substrate. Advantageously, groups Q can also be provided for terminating the copolymer. For example, Q, identical or different, constitutes an anchoring group, 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, catechols (substituted or unsubstituted, such as the catechol group or the nitrocatechol group).

According to another possible variant, Q may be an alkyl chain, preferably C8-C20, used to modify the contact angle obtained or a chain capable of constituting crosslinking points during a complementary crosslinking step (step h). For example, the units P may be derived from stearyl methacrylate.

Preferably, the copolymer of the invention comprises, in molar percentage, between 50% and 99%, preferably between 60% and 95% of N units, between 0% and 50%, preferably between 0%. and 20%, and more preferably between 0% and 10% P units, and when M units or G units are present, between 1% and 50%, preferably between 5% and 40%, and more preferably between 5% and 30% of units M or units G, the percentages being expressed with respect to the total number of units (w + x + y) or (w + x + z).

[0058] Advantageously, the copolymer comprises between 10 and 350 units (w + x + y) or (w + x + z).

The composition in units N and P is similar to the above compositions when the hydrophilic block is the group A 'according to formula III.

In a particularly advantageous manner, the units Μ, N and P are chosen to carry several groups A, preferably of the same nature, several groups L, preferably of the same nature, and optionally one or more groups Q which can be identical or different in nature, so as to refine and improve the properties of the epilame agent, in order to more specifically obtain a universal epilame agent and having an improved affinity with the substrate.

A random copolymer according to the present invention of form (I) is for example a copolymer which has the following structure (la):

wherein the P units are anchor units, the hydrophilic groups are derived from a PEG and the cleavable group is a group

derivative of a UV cleavable nitrobenzyl ester which, after cleavage, will give a -COOH residue in the form of a side chain of the copolymer.

A block copolymer according to the present invention of form (II) is for example a block copolymer which has the following structure (IIa):

wherein the N and P units form an epilam effect block B (the P units being anchoring units), wherein the P units are randomly distributed in the B block, and the M units form a hydrophilic A block in which the hydrophilic groups are randomly distributed, said hydrophilic groups being derived from a PEG and the cleavable groups being groups

UV cleavable nitrobenzyl ester derivatives, which, after cleavage, will give -COOH residues in the form of side chains of the block A copolymer. Such a copolymer is obtained for example by RAFT (reversible chain transfer controlled radical polymerization by addition-fragmentation). In this particular case, the number of links of the block A will not exceed 10, so as to limit the hydrophilicity of the epilame after cleavage of the nitrobenzyl ester function (pendant COOH group).

In another variant not shown, the units P being anchoring units, can form a third anchor block, connected by covalent bond to the epilame block.

A block copolymer according to the present invention of form (III) is for example a block copolymer which has the following structure (Ilia);

wherein the N and P units form an epilam effect block B (the P units being anchor units), wherein the P units are randomly distributed in the B block, and the hydrophilic A block is an A group. hydrophilic derivative of a PEG, the blocks A and B being linked by a cleavable group

derivative of a UV-cleavable nitrobenzyl ester, which, after cleavage, will give a residue -COOH at the end of the main chain of the block B copolymer. Such a copolymer is obtained for example by ATRP (radical transfer copolymerization) at from a functional PEG macroinitiator o-nitrobenzyl bromoisobutyrate, itself obtained by click Chemistry.

A block copolymer according to the present invention of form (IV) is for example a block copolymer which has the following structure (IVa):

in which the units N and P form a block B with epilam effect (the units P being anchoring units as will be seen below), in which the units P are distributed statistically in the block B, and the units P are units G form a hydrophilic block A in which the hydrophilic groups are randomly distributed, said hydrophilic groups being derived from a PEG, the blocks A and B being linked by a cleavable group

derivative of a UV-cleavable nitrobenzyl ester, which, after cleavage, will give a residue -COOH at the end of the main chain of the copolymer of the block B. Such a copolymer is obtained for example by a sequence ATRP / post-polymerization / ATRP functionalization at from an initiator macro.

The present invention also relates to an epilamating bath comprising at least 50% by volume of water, preferably at least 75%, and more preferably 100% by volume of water, and an epilamating agent such as described above, or comprising a copolymer as described above, solubilized in said bath.

The present invention also relates to a process for epilamating at least a portion of a surface of a substrate comprising the steps of: a) preparing an epilamation bath by solubilization of at least one agent epilamate as defined above or comprising at least one copolymer as defined above in a solution containing at least 50% by volume of water, preferably at least 75% by volume of water, and more preferably 100% by volume of water; b) optionally, preparing the surface of the substrate, in particular by cleaning according to standard watchmaking methods; c) contacting the surface of the substrate with the epilamating agent in the epilamination bath; d) optionally, drying; e) separating the hydrophilic group from the epilamating agent by cleavage of the cleavable group, for example according to at least one cleavage treatment as described below, individually, in series or simultaneously; f) rinsing the surface of the substrate; g) drying.

It is obvious that step a) can be implemented remotely in time of the other steps.

Advantageously, step e) is carried out by UV illumination, thermal activation, mechanical stimulus (ultrasound), enzyme treatment, chemical trigger, according to the cleavage technique corresponding to the cleavable group used, or any other compatible with the epilamating agent and the treated surface.

Advantageously, the steps e) and f) are repeated until the hydrophilic residues of the hydrophilic group, that is to say the hydrophilic portion cut off, are removed. For example, step e) can be repeated several times with different cleavage treatments, serially or simultaneously. Steps e) and f) can be repeated up to 5 times to wash and completely remove hydrophilic residues.

Preferably, step f) is carried out in a solution containing at least 50% water, preferably at least 75% water, more preferably 100% water.

Preferably, according to the form of the copolymer used, the preparation of the epilamating agent is carried out by random or block copolymerization of monomers capable of forming the M units with monomers capable of forming the N units, optionally with monomers capable of forming at least one R unit

The random or block copolymerization techniques are well known to those skilled in the art and do not require detailed description. A particularly suitable method of polymerization for random copolymerization is free radical copolymerization, in solution or in emulsion.

According to a first variant, the random copolymer of form (I) 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 XL and optionally monomers carrying side chains WQ.

According to another variant, the random copolymer of the form (I) can be obtained by copolymerization, preferably radical, of monomers bearing the appropriate side Y chains with monomers bearing the appropriate X side chains and optionally monomers carrying chains. laterally designed to carry Q, then the side chains are modified after the polymerization (post-functionalization), for example by "dick chemistry", to introduce the functional groups of interest A, L, and Q groups.

A particularly suitable method of polymerization for block copolymerization is the successive controlled copolymerization:

monomers capable of forming at least one block of units M

monomers capable of forming at least one block of N units, and optionally with monomers capable of forming at least one R unit

Two particularly suitable polymerization methods for block copolymerization are radical transfer copolymerization (ATRP) and controlled radical polymerization controlled by reversible addition-fragmentation chain transfer (RAFT), in solution or in emulsion.

For the copolymer of form (II), according to a first variant, the block copolymer can be obtained by polymerization, preferably controlled radical polymerization, of monomers carrying the side chains Y-A, followed by the copolymerization, preferably controlled radicalization. of monomers carrying side chains XL possibly with monomers bearing side chains WQ.

According to another variant, the block copolymer of form (II) can be obtained by polymerization, preferably controlled radical polymerization, of monomers bearing the appropriate Y side chains, followed by the copolymerization, preferably controlled radical, of monomers bearing the appropriate X side chains suitable with optionally monomers bearing side chains intended to carry Q, then the side chains are modified, for example by "dick Chemistry", to introduce the functional groups of interest A, L and Q groups.

For the copolymers of form (III), the group A 'is first functionalized with a derivative of the cleavable group Y and this new adduct is used as a macro initiator to polymerize the block comprising the N units and optionally P units by controlled radical polymerization ATRP The derivative of the cleavable group Y will be doubly functional: it will comprise both a function allowing the attachment to the group A 'and secondly a group for initiating the polymerization of the block comprising the units P and N. The dick chemistry may in particular be advantageously used to introduce the derivative of the cleavable group Y on the group A '.

For the copolymers of form (IV), the block comprising the units G is formed by controlled radical polymerization ATRP using an initiator having a functional group. This functional group serves in a second step to introduce the cleavable group Y at the end of the block comprising the units G. As described above, this polymer then serves as a macro initiator for the polymerization of the block comprising the P and N units.

Preferably, the monomers are chosen from the group comprising acrylate, methacrylate, acrylamide, methacrylamide, vinyl, diene, styrenic and olefinic monomers. Acrylate, methacrylate, acrylamide, methacrylamide, vinyl and styrene monomers are particularly preferred. These products are for the most part known and available on the market or accessible in a few synthetic steps.

The monomers that are particularly preferred for forming the M units are:

The monomers that are particularly preferred for forming the G units are:

The monomers that are particularly preferred for forming the N and P units are:

Advantageously, the copolymers of the invention can be easily obtained in a limited number of steps from commercial products.

The copolymers used in the invention can be obtained in the form of powder or viscous liquid. They can then be dissolved in an aqueous solvent, at concentrations of preferably between 50 mg / l and 900 mg / l, in order to obtain a solution of epilamating agent, comprising at least 50% of water. preferably 75% water, and more preferably all water, which will be used for the treatment of the surfaces to be epilamed.

According to the variants, the epilamization process according to the invention may furthermore comprise, after step g), a complementary crosslinking step h) made possible in particular by the presence of the appropriate functional groups of interest provided for. on the side chains Q of the R units

The present invention also relates to a substrate comprising a surface at least a part of which is covered with an epilame, characterized in that said epilame has been obtained by cleaving an epilamating agent as defined above or comprising at least one copolymer as defined above, said epilame comprising at least one compound comprising at least hydrophobic and oleophobic groups and at least one residue of a cleavable group which has been used to bind at least one hydrophilic group to said compound .

More particularly, when the epilamating agent comprises a copolymer as described above, the epilame comprises at least one compound in the form of a copolymer comprising N units, and optionally at least one P unit. , covalently linked by their main chains, and at least one remainder of a cleavable group, wherein N and P are as defined above. Depending on the form of the copolymer used in the epilamating agent, the remainder of the cleavable group is at the end of the main chain of the copolymer or at the end of a side chain of the copolymer, said copolymer then comprising only hydrophobic groups and oleophobes with epilame effect.

Depending on the cleavable group used, the remainder of the cleavable group is, for example -COOH, -SH,

or else remains appropriate, at the end of the main chain of the copolymer or at the end of a side chain of the copolymer, said copolymer then comprising only, or very predominantly, hydrophobic and oleophobic groups epilam effect.

Preferably, the surface of the substrate, at least a portion of which is covered with epilame, is made of a material chosen from the group comprising metals, metal oxides, doped or non-doped, polymers, diamond, sapphire. quartz, ruby, silicon, silicon oxides, metal nitrides, especially titanium nitrides, silicon nitrides, metal carbides, in particular tungsten carbides, metal borides, especially tantalum borides, silicon carbides, DLC (Diamond Like Carbon), and their alloys.

More specifically, the surface of the substrate may be made of steel, or of noble metals such as gold, silver, rhodium, palladium, platinum, or metal oxides, doped or non-doped with aluminum, zirconium, titanium, chromium, manganese, magnesium, iron, nickel, copper, zinc, molybdenum, silver, tungsten, or polyoxymethylene or acrylamide, as well as their alloys.

The substrate according to the invention has a surface coated with a simple epilame and economical to synthesize, having an affinity with any type of substrate and an improved washing resistance compared to known epilams. An element or a part having a substrate according to 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 jewelery.

In addition, the process according to the invention, using the epilamating agent or a copolymer according to the invention, is ecological, said epilamating agent or said copolymer being soluble in an aqueous epilamating bath.

Claims (30)

claims An epilamating agent comprising at least one compound comprising at least hydrophobic and oleophobic groups arranged to confer epilamial properties on said compound, and at least one hydrophilic group designed to render said compound soluble in an aqueous medium, said hydrophilic group being bound to the compound by at least one cleavable group. 2. The epilamating agent according to claim 1, characterized in that the hydrophobic and oleophobic groups, which are identical or different, comprise a halogenated, preferably fluorinated C1-C20 carbon group. 3. epilamage agent according to one of claims 1 and 2, characterized in that the hydrophilic group is selected from the group comprising a group derived from a glycol ether, preferably in the form of a grouping derived from a polyether, preferably a group derived from a polyethylene glycol (PEG) or a polypropylene glycol (PPG), a group derived from an amine, preferably in the form of a group derived from a polyamine, a group derived from an alcohol, a carboxylic acid, a sulfonic acid, a phosphonic acid, a carboxylate salt, a sulfonate salt, and a salt thereof; phosphonate. 4. epilamage agent according to one of the preceding claims, characterized in that the cleavable group is a cleavable group by at least one of the treatments selected from the group comprising a UV treatment, a heat treatment, a stimulus treatment mechanical, enzyme treatment, and chemical trigger treatment. 5. The epilamating agent as claimed in claim 4, characterized in that the cleavable group is chosen from the group comprising a group derived from a nitrobenzyl ester, an adduct from a Diels Aider reaction, and a group comprising a dithio function. . 6. epilamage agent according to one of the preceding claims, characterized in that the cleavable group with the associated hydrophilic group form a linear or branched structure with the compound. 7. epilamage agent according to one of the preceding claims, characterized in that the hydrophobic and oleophobic groups form a linear or branched structure with the compound. 8. Copolymer comprising M units, N units, and optionally at least one P unit, covalently linked by their main chains, where wherein R 2, R 3, which may be identical or different, are H, a C 1 -C 10 alkyl, C 1 -C 10 alkenyl, and preferably H, CH 3; W, 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, linear or branched, comprising at least one carbon atom; Y, identical or different, is a group comprising at least one cleavable group; A, identical or different, is a hydrophilic group arranged to render said copolymer soluble in aqueous medium; L, identical or different, is a halogenated C 1 -C 20 carbon-based group, preferably fluorinated; Q, 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 1 carbon atom. 9. Block copolymer comprising at least one block of units N optionally comprising at least one unit P, covalently associated by their main chains, and at least one block comprising at least one hydrophilic group designed to render said copolymer soluble in aqueous medium said blocks being linked together by covalent bonds with at least one cleavable group Y, where N, P, and Y are as defined above. 10. Block copolymer according to claim 9, characterized in that the block comprising at least one hydrophilic group is a group A 'chosen from the group comprising at least one group derived from a glycol ether, preferably in the form of a group derived from a polyether, preferably a group derived from a polyethylene glycol (PEG) or a polypropylene glycol (PPG), and a group derived from an amine, preferably in the form of a group derived from a polyamine, said block copolymer corresponding to formula (III): 11. Block copolymer according to claim 9, characterized in that the block comprising at least one hydrophilic group comprises G units associated by covalent bonds by their main chains, wherein R4, which is the same or different, is H, (C1-C6) alkyl, (C1-C10) alkenyl, and preferably H, CH3; Z, identical or different, is a spacer arm consisting of a heteroatom or a hydrocarbon chain may contain at least one heteroatom, linear or branched, comprising at least one carbon atom; A is as defined above. 12. Copolymer according to one of claims 8 to 11, characterized in that W, X, Z, which are identical or different, are chosen from the group comprising C 1 -C 20, preferably C 2 -C 10, ester groups. amides, and groups derived from styrene. 13. Copolymer according to one of claims 8 to 12, characterized in that Y is a group comprising a group cleavable by at least one of the treatments selected from the group comprising a UV treatment, a heat treatment, a stimulus treatment mechanical, enzyme treatment, and chemical trigger treatment. 14. Copolymer according to claim 13, characterized in that Y is a group comprising a cleavable group chosen from the group comprising a group derived from a nitrobenzyl ester, an adduct from a Diels Aider reaction, and a group comprising a functional group. dithio. 15. Copolymer according to one of claims 8 to 14, characterized in that A is a hydrophilic group selected from the group comprising a group derived from a glycol ether, preferably in the form of a group derived from a polyether, preferably a group derived from a polyethylene glycol (PEG) or a polypropylene glycol (PPG), a group derived from an amine, preferably in the form of a group derived from a polyamine, a group derived from an alcohol, a carboxylic acid, a sulfonic acid, a phosphonic acid, a carboxylate salt, a sulfonate salt and a phosphonate salt. 16. Copolymer according to one of claims 8 to 15, characterized in that L is a C2-C20 carbon group, preferably C4-C10. 17. Copolymer according to one of claims 8 to 16, characterized in that L is an at least partially fluorinated group, preferably completely fluorinated. 18. Copolymer according to one of claims 8 to 17, characterized in that Q, identical or different, is an anchoring group, and is selected from the group consisting of thiols, thioethers, thioesters, sulfides, thioamides, si- lanols, alkoxysilanes, silane halides, hydroxyls, phosphates, protected or unsubstituted phosphonic acids, protected or non-protected phosphonates, amines, ammoniums, nitrogenous heterocycles, carboxylic acids, anhydrides, catechols. 19. The epilamating agent according to claim 1, wherein the compound is a copolymer according to one of claims 8 to 18. 20. Epilamilating bath comprising at least 50% by volume of water and an epilamating agent according to one of claims 1 to 7 or 19 solubilized. 21. Use of a compound comprising at least hydrophobic and oleophobic groups designed to confer on said compound epineous properties, and at least one hydrophilic group arranged to render said compound soluble in aqueous medium, said hydrophilic group being bound to the compound by at least one a cleavable group, as an epilamating agent. 22. Use of a copolymer according to one of claims 8 to 18 as an epilamating agent. 23. A process for epilamating at least a portion of a surface of a substrate comprising the steps of: a) preparing an epilamation bath by solubilizing at least one epilamating agent according to one of claims 1 to 7 or comprising at least one copolymer as defined in claims 8 to 18 in a solution containing at least 50% by volume of water; b) optionally, preparing the surface of the substrate c) contacting the surface of the substrate with the epilamating agent in the epilamination bath d) optionally, drying e) separating the hydrophilic group from the epilamating agent by cleavage f) rinsing the surface of the substrate g) drying. 24. The epilamating process as claimed in claim 23, characterized in that steps e) and f) are repeated until the hydrophilic residues of the hydrophilic group are removed. 25. epilamage process according to one of claims 23 and 24, characterized in that step f) is carried out in a solution containing at least 50% water. 26. Substrate comprising a surface at least a part of which is covered with an epilame, characterized in that said epilame was obtained by cleavage of an epilamating agent according to one of claims 1 to 7 or comprising at least one copolymer as defined in claims 8 to 18, said epilam comprising at least one compound comprising at least hydrophobic and oleophobic groups and at least one residue of a cleavable group which has been used to bind at least one hydrophilic group to said compound. 27. Substrate according to claim 26, characterized in that the epilame comprises at least one compound in the form of a copolymer comprising N units, and optionally at least one P unit, covalently linked by their main chains, and at least one residue of a cleavable group, wherein N and P are as defined above. 28. Substrate according to claim 27, characterized in that the remainder of the cleavable group is at the end of the main chain of the copolymer or at the end of a side chain of the copolymer. 29. Substrate according to one of claims 26 to 28, characterized in that its surface, at least part of which is covered with epilame, is made of a material selected from the group consisting of metals, metal oxides, metal nitrides, metal borides, metal carbides, polymers, diamond, sapphire, ruby, quartz, silicon, silicon oxides, silicon nitrides, silicon carbides, diamond-like carbon (DLC), and their alloys. 30. Timepiece or jewelery comprising an element comprising a substrate according to any one of claims 26 to 29.