Method for applying a non-halogenated epilame coating by cold-plasma spraying at atmospheric pressure

Abstract

The invention relates to a method for applying a watchmaking oleophobic and hydrophobic non-halogenated epilame coating that is resistant to timepiece cleaning, to at least part of a surface of a substrate, using atmospheric-pressure cold-plasma coating, the method comprising: activating a first carrier gas using a first electrical discharge, thus creating a first plasma gas jet having an overall temperature equal to or lower than 200°C; introducing an anchoring compound into said first plasma gas jet, thereby activating the anchoring compound; bringing said surface into contact with said first plasma gas jet comprising said activated anchoring compound, thereby causing the anchoring compound to adhere to said surface; activating a second carrier gas using a second electrical discharge, thereby creating a second plasma gas jet having an overall temperature equal to or lower than 200°C; introducing an epilame-coating compound into said second plasma gas jet, thereby activating the epilame-coating compound; and bringing said surface to which the anchoring compound is adhered into contact with said second plasma gas jet comprising said activated epilame-coating compound, thereby causing the epilame-coating compound to adhere to said anchoring compound and thereby forming on said surface a non-halogenated oleophobic and hydrophobic epilame coating resistant to timepiece cleaning; wherein the anchoring compound is in the form Si(OR)xR''y(R'NH2)4-x-y, where R and R'', which may be identical or different, are H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, R', which may be identical or different, is H, a C1-C10 alkyl group optionally comprising an amine group, or a C2-C10 alkenyl group optionally comprising an amine group, x is 1, 2 or 3, y is 0 or 1 where x+y is 0, 1, 2 or 3; and the epilame-coating compound is according to formula (II) or according to formula (III): (II), where R1, R2, R3, R4, R5, R6, R7 and R8, which may be identical or different, are H, a C1-C10 alkyl group or a C2-C10 alkenyl group, and n is comprised between 0 and 10, in which at least one of R1, R2 or R3 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl, and at least one of R4, R5 or R6 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl; or (III), where R9, R10, R11, R12, R13 and R14, which may be identical or different, are H, a C1- C10 alkyl group, or a C2-C10 alkenyl group, m is comprised between 1 and 10, in which at least one of R9, R10, R11, R12, R13 and R14 is a C1-C10 alkyl group or a C2-C10 alkenyl group.

Description

P7350WQ01 / TR NON-HALOGENATED HAIR REMOVAL PROCESS USING COLD PLASMA AT ATMOSPHERIC PRESSURE Technical field of the invention

[0001] The present invention relates to methods for applying oleophobic and hydrophobic, non-halogenated, watchmaking-resistant cold plasma coatings to at least a portion of a substrate surface. More particularly, the invention relates to cold plasma coating methods using non-halogenated compounds. The resulting coating is an oleophobic and hydrophobic, non-halogenated, watchmaking-resistant coating. Technological background

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

[0003] However, the substances currently used for hair removal have several drawbacks. One of these drawbacks is their fluorinated nature.

[0004] EP 3,070,133 describes an epilame agent comprising a block copolymer including a fluorinated motif, an anchoring motif, and optionally an additional hydrocarbon chain. EP 3,070,152 describes an epilame agent comprising a block copolymer including a fluorinated motif, an anchoring motif, and optionally an additional hydrocarbon chain. The disclosed fluorinated motifs are linear perfluorinated alkyl chains of the type -CXF2X+I, specifically -CeF and -CsFi?.

[0005] It is known that epilators containing linear chains of the -CXF2X+I type pose environmental and health problems related to per- and polyfluoroalkyl substances (PFAS), particularly perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). These linear (per)fluorinated chains can be transformed into persistent PFAS during their manufacture or degradation in the environment. PFAS, and especially PFOA and PFOS, are extremely stable, persisting in the environment and accumulating in living organisms (bioaccumulation), with toxic effects. Furthermore, many PFAS, such as PFOA and PFOS, are molecules that, upon degradation, decompose into trifluoroacetic acid (TFA), which is water-soluble. They therefore readily contaminate water resources, making their purification complex.Because of these impacts, international regulations are increasingly restricting the use of PFAS, as well as that of any substance that can be transformed into PFAS, including linear (per)fluorinated chains.

[0006] Another drawback is that their application requires high consumption of fluorinated solvents or water, making the processes neither environmentally friendly nor economical.

[0007] Patent EP 3 101 170 B1 describes a vacuum cold plasma polymerization process using an organosilane monomer as a precursor. A durable water repellent (DWR) nanocoating (a coating with a thickness on the order of nanometers) is deposited onto a textile product using this process. The process involves polymerizing excited monomers directly on the surface of the textile product. A specific example of the monomer that is polymerized is hexamethyldisiloxane (HMDSO).

[0008] One drawback of this process is that it requires a pressure lower than atmospheric pressure, and therefore a reaction chamber capable of withstanding these low pressures, as well as pumps and other equipment to achieve and maintain this low pressure throughout the process. Another drawback is that the precursors must be monomers capable of undergoing polymerization. Summary of the invention

[0009] The invention aims in particular to overcome the various drawbacks of known hair removal agents and hair removal processes.

[0010] More specifically, one objective of the invention is to provide a non-halogenated, in particular non-fluorinated, epilaming process. In other words, one objective of the invention is to provide an epilaming process applying a non-halogenated epilam coating to a substrate surface.

[0011] In this disclosure, the term "epilame effect" is used to indicate a hydrophobic and oleophobic effect. An epilame coating is therefore used for a coating that is not only hydrophobic but also oleophobic.

[0012] One objective of the invention is therefore to provide an environmentally friendly hair removal process. On the one hand, the environmental benefit is achieved through the non-halogenated nature of the product. On the other hand, the processes according to the present invention eliminate the use of a significant amount of solvents, including expensive fluorinated solvents and also water, contributing to both the environmental and economic aspects of the processes.

[0013] The invention also aims to provide a de-epilating process resulting in a de-epilating coating with good wash resistance, particularly to the washes used in watchmaking. The invention further aims to provide a universal de-epilating process that can be used with any type of material.

[0014] The invention also aims to provide a simple and economical process. In particular, the objective is to provide a de-epilating process capable of processing a large quantity of substrates (parts or components) simultaneously (i.e., bulk processing). Specifically, the objective is to provide a de-epilating process that does not require vacuum processing. This also simplifies the equipment, because the processes do not require means to generate an environment at a pressure lower than atmospheric pressure.

[0015] To this end, a first aspect of the present invention relates to an oleophobic and hydrophobic, non-halogenated watchmaking waxing process resistant to watch washing according to the attached claims.

[0016] The oleophobic and hydrophobic, non-halogenated, and watch wash-resistant epilaming process is a cold plasma process at atmospheric pressure. Using this cold plasma process at atmospheric pressure, an oleophobic and hydrophobic, non-halogenated, and watch wash-resistant epilaming coating is applied to a portion of a substrate surface.

[0017] The term "cold plasma" is used in this disclosure for a plasma in which the electrons are highly energetic (at high temperature) but the overall plasma gas temperature is equal to or less than 200 °C, preferably equal to or less than 150 °C, more preferably equal to or less than 100 °C, for example, equal to or less than 75 °C, and even more preferably equal to or less than 50 °C, such as room temperature. At such an overall plasma gas temperature, components heavier than electrons in the plasma gas, such as radical components and ions, remain at a low temperature (specifically, at or around the overall plasma gas temperature). Consequently, damage, fragmentation, and degradation of these components can be avoided. Furthermore, damage and degradation of sensitive substrates, e.g., polymeric (plastic) substrates, can also be avoided.

[0018] The oleophobic and hydrophobic, non-halogenated, watchmaking-wash resistant epilame coating comprises at least two layers. A first layer, in direct contact with the substrate surface, is advantageously an anchoring layer. The second layer, i.e., the top layer, is advantageously an epilame layer.

[0019] The process therefore involves bonding a first anchoring layer to at least a portion of the surface of a substrate to be epilaminated. This first anchoring layer provides good adhesion of the epilamine coating to the substrate surface. Good adhesion is known to contribute to the long-lasting effect of a coating, and in this case, good adhesion contributes to the washout resistance of the epilamine coating.

[0020] The process involves activating a first carrier gas by a first electrical discharge. The activation of the first carrier gas results in (creates) a first jet of plasma gas.

[0021] The term "activation of a gas or compound" in this disclosure refers to the process of exciting and / or ionizing a gas and / or compound without fragmenting it, thereby generating reactive species, including ions, radicals, and electrons. These reactive species are capable of interacting with a substrate surface and / or initiating chemical reactions.

[0022] An anchoring compound is introduced into the first plasma gas jet. When exposed to the reactive species of the plasma gas, the anchoring compound is activated without being fragmented, thus creating a first plasma gas jet comprising a reactive form of the anchoring compound.

[0023] The portion of the substrate surface to be treated is then brought into contact with the first jet of plasma gas containing the activated anchoring compound. During contact, the activated anchoring compound reacts with the surface, resulting in its adhesion. A first anchoring layer is thus formed (applied).

[0024] In this disclosure, the reaction of a compound during a contact step with a substrate surface advantageously results in its application to that surface, in the form of a deposit, attachment, or adhesion. This application includes the formation of covalent bonds between the molecules of the compound and those of the contacted surface. Optionally, covalent bonds may also form between molecules of the activated compound. It is known that covalent bonds between a compound and a substrate surface generally contribute to good adhesion of the compound coating to the surface.

[0025] Advantageously, covalent bonds between the activated anchoring compound and the substrate surface are therefore formed during the reaction of the activated anchoring compound with the surface.

[0026] The anchoring compound is a non-halogenated compound according to formula (I) Si(OR)xR"y(R'NH2)4-xy (I), where R and R”, identical or different, are H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, R', identical or different, is H, an alkyl group in C1-C10 optionally comprising an amine group, or an alkenyl group in C2-C10 optionally comprising an amine group, x is 1, 2 or 3, preferably 3, and y is 0 or 1, in which x + y is 1, 2 or 3.

[0027] The process also includes the adhesion of a second epilame layer to the anchoring layer.

[0028] Next, a second carrier gas is activated by a second electrical discharge. The activation of the second carrier gas results in (creates) a second jet of plasma gas.

[0029] An epilamage compound is introduced into the second plasma gas jet. When exposed to reactive species in the plasma gas, the epilamage compound is activated without being fragmented, thus creating a second plasma gas jet containing a reactive form of the epilamage compound.

[0030] The portion of the substrate surface comprising the first layer is then brought into contact with the second plasma gas jet containing the activated epilaming compound. During this contact, the activated epilaming compound reacts with the anchoring compound forming the first layer, resulting in the epilaming compound adhering to the first layer. A second epilaming layer is thus formed (applied). Advantageously, covalent bonds are formed with the anchoring compound during the reaction of the activated epilaming compound. Optionally, covalent bonds are also formed between molecules of the activated epilaming compound.

[0031] The first anchoring layer and the second epilame layer together form the epilame coating.

[0032] The epilamage compound is a non-halogenated compound according to formula (II) or formula (III): (H), where R 1, R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 , identical or different, are H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl, in which at least one of R 1 , R 2 or R 3 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl, and at least one of R 4 , R 5 or R 6 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl, and n is between 0 and 10, preferably between 0 and 6, more preferably between 0 and 4; Or R 9 , R 10 , R 11 , R 12 , R 13 and R 14 , identical or different, are H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, preferably methyl or ethyl, in which at least one of R 9 , R 10 , R 11 , R 12 , R 13 and R 14 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl, and m is between 1 and 10, preferably between 1 and 6, more preferably between 1 and 4.

[0033] The epilame coating obtained using the epilame compound according to formula (II) is advantageously a silicone-type coating.

[0034] Advantageously, the epilamage compound according to formula (II) is tetramethyldisiloxane (TMDSO), hexamethyldisiloxane (HMDSO), or a combination thereof.

[0035] Advantageously, the anchoring compound is (3-aminopropyl)triethoxysilane (APTES), (3-aminopropyl)trimethoxysilane (APTMS), or a combination thereof.

[0036] Unlike known processes using non-halogenated compounds (particularly non-fluorinated compounds), especially those using cold plasma, the inventors have surprisingly discovered that the cold plasma processes according to the present invention, using specific anchoring and epilaming compounds, allow the formation of epilam coatings on a surface. These coatings exhibit not only hydrophobic but also oleophobic properties. They are non-halogenated. Furthermore, these coatings are resistant to watchmaking washing.

[0037] Without wishing to be bound to any particular theory, the inventors believe that this oleophobic effect results from the combination of a two-layer coating, specific compounds for each layer, and a synergy between compounds (between the two layers) that appears to enhance the epilame effect, and the use of a cold plasma. The latter is considered to allow the deposition of these specific compounds with a high functional density, while preventing their degradation.

[0038] Advantageously, the anchoring compound is introduced into the first plasma gas jet as an aerosol. Advantageously, the depilating compound is introduced into the second plasma gas jet as an aerosol. An aerosol comprising or consisting of the respective compound (anchoring or depilating) can be obtained by processes known in the art, e.g., by nebulizing a liquid comprising or consisting of the respective compound.

[0039] Advantageously, the first carrier gas and the second carrier gas, whether identical or different, are inert gases, preferably nitrogen and / or argon. That is, the first carrier gas and the second carrier gas may be identical or different, and are each inert gases.

[0040] Advantageously, when the first plasma gas jet comprising the activated anchoring agent comes into contact with the substrate surface, the substrate and the first plasma gas jet are displaced relative to each other.

[0041] Advantageously, when the second plasma gas jet comprising the activated epilamage agent comes into contact with the substrate surface, the substrate and the second plasma gas jet are displaced relative to each other.

[0042] It goes without saying that such relative motion implies that the plasma gas jet and the surface can move at different speeds or in different directions relative to each other, or that one can be in motion while the other remains stationary. Relative motion can be achieved by means known in the field of plasma treatments.

[0043] Advantageously, when the substrate and the first plasma gas jet are moved relative to each other, at least a portion of the surface is brought into contact with the first plasma gas jet comprising the anchoring compound in several passes.

[0044] Advantageously, when the substrate and the second plasma gas jet are moved relative to each other, the portion of the surface to which the anchoring compound is adhered is brought into contact with the second plasma gas jet comprising the epilamage compound in several passes.

[0045] A multi-pass contacting process allows control of the contact conditions, and also allows for obtaining a thicker layer in a controlled manner.

[0046] Advantageously, the first plasma gas jet containing the anchoring compound is generated in a plasma discharge chamber. Advantageously, at least a portion of the substrate surface is brought into contact with residual plasma (afterglow) from the first plasma gas jet containing the anchoring compound originating from the plasma discharge chamber.

[0047] Advantageously, the second plasma gas jet containing the epilamage compound is generated in a plasma discharge chamber. Advantageously, at least a portion of the substrate surface is brought into contact with residual plasma (afterglow) from the second plasma gas jet containing the epilamage compound originating from the plasma discharge chamber.

[0048] Advantageously, the first carrier gas has a first flow rate and said anchoring compound is introduced into the first plasma gas at an anchoring flow rate, wherein the ratio of the first flow rate to the anchoring flow rate is between 10:1 and 250:1, preferably between 25:1 and 200:1, more preferably between 50:1 and 100:1.

[0049] Advantageously, the second carrier gas has a second flow rate and said epilamage compound is introduced into the second plasma gas at an epilamage flow rate, and the ratio of the second flow rate to the epilamage flow rate is between 10:1 and 250:1, preferably between 25:1 and 200:1, more preferably between 50:1 and 100:1.

[0050] Advantageously, the process includes a surface preparation step for the substrate prior to contact with the plasma gas jet containing the activated anchoring compound. Surface preparation is advantageously carried out using methods known in the art, e.g., surface cleaning to eliminate any possible contamination.

[0051] Advantageously, the surface of the substrate, at least a portion of which is subjected to the epilaming process according to the invention, is made of a material selected from the group comprising metals, metal oxides, polymers, sapphire, ruby, silicon, silicon oxides, silicon nitrides, silicon carbides, diamond-like carbon (DLC), and their alloys. An example of such a metal alloy, particularly valued in the watchmaking industry, is the NiP alloy.

[0052] Advantageously, the substrate is a watch or jewelry component. In other words, advantageously at least a portion of the surface of a watch or jewelry component is subjected to the depilation process according to the invention. Brief description of the figures

[0053] The goals, advantages, and characteristics are demonstrated in the following figures, which are not exhaustive, and in which: - Figure 1 represents the contact angles measured on different substrates whose surface is coated with a reference fluorinated epilame agent, - Figure 2 represents the contact angles measured on different substrates whose surface is coated with an epilame agent according to the methods of the invention. Detailed description of the invention

[0054] According to the present invention, a substrate comprises a surface, at least a portion of which is treated by the epilaming processes of the invention. Advantageously, at least the surface of the substrate, and optionally the entire substrate, is made of a material selected from the group comprising metals, metal oxides, polymers, sapphire, ruby, silicon, silicon oxides, silicon nitrides, silicon carbides, diamond-like carbon (DLC), and their alloys.

[0055] Advantageously, the substrate surface comprises or substantially consists of a metallic alloy. A preferred example of a metallic alloy, particularly valued in watchmaking, is NiP, an alloy consisting primarily of nickel and phosphorus. NiP may have a low phosphorus content (typically between 2% and 5% by weight), a medium phosphorus content (typically between 6% and 9% by weight), or a high phosphorus content (typically between 10% and 13% by weight, for example, 12% by weight).

[0056] Alternatively, and advantageously, the substrate surface may comprise or be made of steel, or of noble metals such as gold, rhodium, palladium, platinum, or combinations of two or more of them, or of metal oxides, doped or undoped, of aluminum, zirconium, titanium, chromium, manganese, magnesium, iron, nickel, copper, zinc, molybdenum, silver, tungsten, or combinations of two or more of them, or of polyoxymethylene or acrylamide, and their alloys.

[0057] Advantageously, in the present invention, the substrate is a substrate of an element of a watch or jewelry part.

[0058] The atmospheric pressure cold plasma epilaming processes according to the present invention comprise an operation of depositing a first layer onto at least a portion of a substrate surface as described above, and an operation of depositing a second layer onto the first layer. The first and second layers together form an epilam coating, i.e., a hydrophobic and oleophobic coating, which is also resistant to watchmaking washing.

[0059] The operation of depositing a first layer includes the steps of activating a first carrier gas, introducing an anchoring compound, and bringing a first jet of plasma gas into contact with the surface of the substrate.

[0060] A first jet of plasma gas is created by activating a first carrier gas. Advantageously, the first carrier gas is an inert gas, a reactive gas, or a combination of one or more inert and / or reactive gases. Non-limiting examples of inert gases include nitrogen, argon, and helium, of which nitrogen is a preferred example. Non-limiting examples of reactive gases include oxygen, hydrogen, and ammonia. Advantageously, the first carrier gas is nitrogen.

[0061] The activation of the first carrier gas can be achieved by methods known in the field of plasma generation. Advantageously, in the present disclosure, the first carrier gas is activated by a first electrical discharge.

[0062] Advantageously, the first electrical discharge is carried out at a power between 25 W and 2000 W, preferably between 50 W and 1500 W, more preferably between 100 W and 1000 W, even more preferably between 250 W and 750 W, for example between 400 W and 450 W. It goes without saying that the optimal power depends on the device used, and also on the flow rate of the first carrier gas.

[0063] Advantageously, the flow rate of the first carrier gas (the initial flow rate) is between 10 sim (standard liters per minute) and 250 sim, preferably between 20 sim and 200 sim, more preferably between 30 sim and 150 sim, e.g., between 40 sim and 125 sim or between 50 sim and 100 sim. It goes without saying that the optimal flow rate of the first carrier gas depends, among other things, on the device used for generating the first plasma jet.

[0064] Once the first plasma gas jet is generated, at least one anchoring compound is introduced into it. Under the action of reactive species in the first plasma gas jet, the anchoring compound(s) is / are activated.

[0065] The anchoring compound is a non-halogenated compound according to formula (I) Si(OR)xR"y(R'NH2)4-xy (I).

[0066] Advantageously, R and R”, identical or different, are H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, and preferably a C1-C6 alkyl group, more preferably a C1-C4 alkyl group, for example methyl, ethyl, n-propyl, or isopropyl. R' and R”, identical or different, may be linear or branched.

[0067] Advantageously, R', identical or different, is H, a C1-C10 alkyl group optionally comprising an amine group, or a C2-C10 alkenyl group optionally comprising an amine group. The R' group may be linear or branched. The optional amine group may be a primary or secondary amine group. Preferably, R' is a C1-C6 alkyl group, more preferably a C1-C4 alkyl group, for example, n-propyl or n-butyl. R' may be linear or branched.

[0068] Advantageously, x is 1, 2, or 3, preferably 3. Advantageously, y is 0 or 1, and x + y is 1, 2, or 3. When x + y is 1, it follows that x is 1 and y is 0. When x + y is 2, it follows that x and y are 1, or x is 2 and y is 0. When x + y is 3, it follows that x is 2 and y is 1, or x is 3 and y is 0.

[0069] Non-limiting examples of anchoring compounds include (3-aminopropyl)triethoxysilane (APTES; in formula (I) R is ethyl, R' is n-propyl, x is 3 and y is 0 (x + y being 3)), (3-aminopropyl)trimethoxysilane (APTMS; in formula (I) R is methyl, R' is n-propyl, x is 3 and y is 0 (x + y being 3)), (4-aminobutyl)triethoxysilane (CAS 3069-30-5; in formula (I) R is ethyl, R' is n-butyl, x is 3 and y is 0 (x + y being 3)), N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane (CAS 3069-29-2; in formula (I) R is methyl, R'NH2 is N-(2-aminoethyl)-3-aminopropyl, R” is methyl, x is 2 and y is 1 (x + y being 3)) and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (CAS 1760-24-3; in formula (I) R is methyl, R'NH2 is N-(2-aminoethyl)-3-aminopropyl, x is 3 and y is 0 (x + y being 3)).

[0070] Advantageously, the flow rate of the anchoring compound (the anchoring flow rate) is between 0.1 sim and 20 sim, preferably between 0.2 sim and 10 sim, more preferably between 0.25 sim and 5 sim, and even more preferably between 0.5 sim and 1 sim. It goes without saying that the optimal flow rate of the anchoring compound depends, among other things, on the apparatus used for generating the first plasma gas jet and the flow rate of the first carrier gas.

[0071] Advantageously, the ratio of the first flow to the anchor flow is between 10:1 and 250:1, preferably between 25:1 and 200:1, more preferably between 50:1 and 100:1.

[0072] The first jet of plasma gas containing the activated anchoring compound is then brought into contact with the substrate surface, thus forming the first layer.

[0073] Advantageously, the contact has a duration of between 10 seconds and 60 minutes, preferably between 20 seconds and 45 minutes, for example between 30 seconds and 30 minutes, or between 45 seconds and 20 minutes, more preferably between 1 minute and 10 minutes, even more preferably between 2 minutes and 5 minutes.

[0074] Optionally, before the substrate surface comes into contact with the first plasma jet, the substrate surface can be prepared. Surface preparation can contribute to better anchoring (adherence) of the first layer to the surface.

[0075] Optional substrate surface preparation may include cleaning and / or washing the surface to be epilamed. Such cleaning or washing helps remove any surface contaminants, such as dust and residues like grease.

[0076] Optional cleaning or washing can be carried out using methods known to those skilled in the art. For example, and particularly when the substrate is a watch component, cleaning may include standard watchmaking procedures.

[0077] Alternatively, substrate surface preparation may include plasma pretreatment, and may include contact with the plasma gas jet before introducing the anchoring compound into it.

[0078] Alternatively, substrate surface preparation can include CO2 treatment at a temperature between 10°C and 80°C and a pressure between 25 bar and 250 bar, for example, for a duration of 1 to 60 minutes. Such treatment advantageously removes dust particles and degreases the surface.

[0079] Advantageously, the initial contact with the plasma gas jet can include contacting a plurality of substrates with the activated anchoring compound. In other words, the methods according to the present invention allow for the application (deposition) of an epilamal coating to at least a portion of a surface of a plurality of substrates. In other words, the methods according to this disclosure allow for bulk processing.

[0080] According to a first embodiment of bulk treatment, the surfaces of the substrates to be treated are brought into contact with the first plasma gas jet (and thus the activated anchoring compound) simultaneously. In other words, this first embodiment is a static mode, in the absence of relative movement between the plasma gas jet and the substrates.

[0081] According to a second embodiment of bulk processing, the initial plasma gas jet and the substrates are displaced relative to each other. For example, the plasma gas jet can be moved to bring each substrate into contact with the activated anchoring compound, one after the other (or several, but not all, substrates simultaneously). Such relative movement can be achieved using methods known in the field of plasma processing, particularly atmospheric plasma.

[0082] It goes without saying that the method of carrying out an optimal bulk treatment depends, among other things, on the apparatus used to carry out the process of the invention, and the number and dimensions of the substrates.

[0083] Following the operation of depositing the first layer on the surface of the substrate, the operation of depositing a second layer on top of the first layer takes place.

[0084] The operation of depositing a second layer includes the steps of activating a second carrier gas, introducing an epilamage compound, and bringing a second jet of plasma gas into contact with the surface of the substrate comprising the first layer.

[0085] A second plasma gas jet is created by activating a second carrier gas. Advantageously, the second carrier gas is an inert gas, a reactive gas, or a combination of one or more inert gases and / or one or more reactive gases, as described above for the first carrier gas.

[0086] When the second carrier gas is identical to the first carrier gas, the activation step of the second carrier gas includes the continuation of the activation of the first carrier gas.

[0087] When the second carrier gas is different from the first carrier gas, the activation step of the second carrier gas includes stopping the activation of the first carrier gas and activating the second carrier gas.

[0088] The operation of depositing the second layer advantageously also includes stopping the introduction of the anchoring compound.

[0089] The activation of the second carrier gas can be achieved by methods known in the field of plasma generation. Advantageously, in the present disclosure, the second carrier gas is activated by a second electrical discharge.

[0090] Advantageously, the second electrical discharge is carried out at a power between 25 W and 2000 W, preferably between 50 W and 1500 W, more preferably between 100 W and 1000 W, even more preferably between 250 W and 750 W, for example between 400 W and 450 W. It goes without saying that the optimal power depends on the device used, and also on the flow rate of the second carrier gas.

[0091] Advantageously, the flow rate of the second carrier gas (the second flow rate) is between 10 sim (standard liters per minute) and 250 sim, preferably between 20 sim and 200 sim, more preferably between 30 sim and 150 sim, e.g., between 40 sim and 125 sim or between 50 sim and 100 sim. It goes without saying that the optimal flow rate of the second carrier gas depends, among other things, on the device used for generating the second plasma jet.

[0092] Once the second plasma gas jet is generated, at least one epilamage compound is introduced into it. Under the action of reactive species in the second plasma gas jet, the epilamage compound(s) is / are activated.

[0093] The epilamage compound is a non-halogenated compound according to formula (II)

[0094] Advantageously, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 The identical or different components are H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, and preferably H or a C1-C6 alkyl group, more preferably H or a C1-C4 alkyl group, for example methyl or ethyl. R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 , identical or different, can be linear or branched.

[0095] Advantageously, at least one, and preferably at least two, of R 1 , R 2 or R 3 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably a C1-C6 alkyl group, more preferably methyl or ethyl.

[0096] Advantageously, at least one, and preferably at least two, of R 4 , R 5 or R 6 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably a C1-C6 alkyl group, more preferably methyl or ethyl.

[0097] Advantageously, n is between 0 and 10, preferably between 0 and 6, more preferably between 0 and 4.

[0098] Non-limiting examples of depilatory compounds according to formula (II) include tetramethyldisiloxane (TMDSO; one of R 1 , R 2 or R 3 being H and the other two being methyl, one of R 4 , R 5 or R 6(H and the other two being methyl, and n being 0), hexamethyldisiloxane (HMDSO; R 1 , R 2 , R 3 , R 4 , R 5 and R 6 (all methyl groups and n being 0), octamethyltrisiloxane (CAS 107-51-7, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 (all methyl groups and n being 1), the 1,1,1,3,5,5,5-heptamethyletrisiloxane (CAS 1873-88-7, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 being methyl, R 8 (where H and n is 1), 1,1,3,3,5,5-hexamethyltrisiloxane (CAS 1189-93-1, R 1 , R 2 , R 4 , R 5 , R 7 and R 8 being methyl, R 3 and R 6 (where H and n is 1), decamethyltetrasiloxane (CAS 141-62-8, R 1 , R 2 , R 3 , R 4 , R 5 , R 6, R 7 and R 8 (all methyl and n being 2), dodecamethylpentasiloxane (CAS 141-63-9, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 being all methyl and n being 3) and tetradecamethylhexasiloxane (CAS 107-52-8, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 being all methyl and n being 4).

[0099] Alternatively, and advantageously, the epilamage compound is a cyclic non-halogenated compound according to formula (III) (III).

[0100] Advantageously, R 9 , R 10 , R 11 , R 12 , R 13 and R 14The identical or different components are H, a C1-C10 alkyl group, or a C2-C10 alkenyl group, and preferably H or a C1-C6 alkyl group, more preferably H or a C1-C4 alkyl group, for example methyl or ethyl. R 9 , R 10 , R 11 , R 12 , R 13 and R 14 , identical or different, can be linear or branched.

[0101] Advantageously, at least one, and preferably at least two, of R 9 , R 10 , R 11 , R 12 , R 13 and R 14 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably a C1-C6 alkyl group, more preferably methyl or ethyl.

[0102] Advantageously, m is between 1 and 10, preferably between 1 and 6, more preferably between 1 and 4.

[0103] Non-limiting examples of epilamage compounds according to formula (III) include hexamethylcyclotrisiloxane (CAS 541-05-9, R 9 , R 10 , R 11 , R 12 , R 13 and R 14 (all methyl and m being 1), octamethylcyclotetrasiloxane (CAS 556-67-2, R 9 , R 10 , R 11 , R 12 , R 13 and R 14 (all methyl and m being 2), tetramethylcyclotetrasiloxane (CAS 2370-88-9, R 9 , R 11 and R 13 being methyl, R 10 , R 12 and R 14 (H and m being 2), decamethylcyclopentasiloxane (CAS 541-02-6, R 9 , R 10 , R 11 , R 12 , R 13 and R 14 being all methyl and m being 3) and dodecamethylcyclohexasiloxane (CAS 540-97-6, R 9 , R 10 , R 11 , R 12 , R 13 and R 14 being all methyl and m being 4).

[0104] Advantageously, the flow rate of the epilaming compound (the epilaming flow rate) is between 0.1 sim and 20 sim, preferably between 0.2 sim and 10 sim, more preferably between 0.25 sim and 5 sim, and even more preferably between 0.5 sim and 2 sim. It goes without saying that the optimal flow rate of the epilaming compound depends, among other things, on the device used for generating the second plasma gas jet and the flow rate of the second carrier gas.

[0105] Advantageously, the ratio of the second flow rate to the epilation flow rate is between 10:1 and 250:1, preferably between 25:1 and 200:1, more preferably between 50:1 and 100:1.

[0106] The second jet of plasma gas comprising the activated epilamage compound is then brought into contact with the surface of the substrate comprising the first layer, thus forming the second layer, and therefore the epilame coating.

[0107] Advantageously, the contact has a duration of between 10 seconds and 60 minutes, preferably between 20 seconds and 45 minutes, for example between 30 seconds and 30 minutes, or between 45 seconds and 20 minutes, more preferably between 1 minute and 10 minutes, even more preferably between 2 minutes and 5 minutes.

[0108] Just as with the contact of the substrate surface and if it is a bulk processing, the surfaces of the substrates including the first layer can be brought into contact with the second plasma gas jet including the epilamage compound activated simultaneously (static mode) or by moving the second plasma gas jet and the substrates relative to each other.

[0109] Preferably, the two contacting steps are carried out in the same way, that is, each in static mode or each by relative movement.

[0110] Several substrates with different compositions were used to evaluate the epilame effect obtained by a reference epilame agent, of the fluorinated type, applied by the conventional dipping process, and the epilame effect obtained by the processes of the present invention, the epilame coating obtained being a non-halogenated coating.

[0111] As a reference, a fluorinated depilating agent according to EP3070133 was applied by the conventional dipping method. The depilating agent contained a -(CF2)s-CF3 group as its hydrophobic L group. A depilating bath containing the fluorinated depilating agent was prepared, and the various substrates were dipped into this bath to apply a fluorinated depilating coating.

[0112] A coating according to the present invention was also applied to the same types of substrates by a bulk treatment, i.e., a treatment applied to all substrates simultaneously. A PLASMASPOT® device from MPG was used. Nitrogen as the carrier gas was activated by an electrical discharge with a power of 400 W, creating a nitrogen plasma as the plasma gas jet. The nitrogen flow rate was 80 sim (standard liters per minute). (3-Aminopropyl)triethoxysilane (CAS919-30-2) as an anchoring compound was nebulized and introduced into the plasma gas jet as an aerosol at a flow rate of 0.8 sim, while maintaining the power of 400 W to activate the (3-Aminopropyl)triethoxysilane (and the nitrogen) in the plasma gas jet. The substrates were brought into contact with the plasma gas jet containing activated (3-aminopropyl)triethoxysilane by moving and holding the equipment in which the plasma gas jet was formed in a fixed position.The substrates were moved in a circular motion for 5 minutes. This contact resulted in the deposition of a first coating layer consisting of (3-aminopropyl)triethoxysilane onto the substrate.

[0113] Next, the introduction of (3-aminopropyl)triethoxysilane into the plasma jet was stopped. Tetramethyldisiloxane (CAS 3277-26-7), as the epilaminate compound, was nebulized and introduced into the plasma jet (still a nitrogen plasma generated at 400 W) as an aerosol at a flow rate of 1.2 sim, while maintaining the 400 W power to activate the (tetramethyldisiloxane) and nitrogen. The substrates were contacted with the plasma jet containing the activated tetramethyldisiloxane in the same way as with the plasma jet containing the activated (3-aminopropyl)triethoxysilane, also for a duration of 5 minutes. This resulted in the deposition of a second layer of tetramethyldisiloxane over the first layer, thus forming a silicone-like epilaminate coating on the substrates.

[0114] The oleophobicity of the reference (fluorinated) epilame coating and the epilame coating according to the invention (non-halogenated) was determined. The procedure, known to those skilled in the art, consists of measuring (using a Dataphysics OCA 15 contact angle measuring device) the contact angles of drops of two oils: test oil No. 3 and Synth-A-Lube 9010 watch oil, both from Moebius®. Oil No. 3 is known to be highly selective (discriminating) in that it is capable of revealing epilame problems.

[0115] To assess resistance to watchmaking washes, some of the substrates were washed three times according to a watchmaking wash (amine hydrocarbon solution), followed by measurement of the contact angles with the same oils.

[0116] The target values ​​for each measure are as follows: - Test oil no. 3 - initial (before washing): 60° - Test oil no. 3 - after 3 washes: 35° - Synth-A-Lube 9010 watch oil - initial: 70° - Synth-A-Lube 9010 watch oil - after 3 washes: 45°

[0117] Figure 1 shows the results on different substrates for the reference fluorinated coating. Figure 2 shows the results on the same substrates for the non-halogenated coating according to the processes of the invention.

[0118] It is clear from Figure 1 that the target value for oil #3 is achieved for only four of the seven substrates, and after washing, for only two of the seven substrates. In contrast, the target values ​​for Synth-A-Lube 9010 watch oil are achieved, except for the 12% NiP substrate after three washes.

[0119] Figure 2 shows that the epilame coating of the invention does not achieve the target values ​​for oil No. 3 on any substrate. This can be explained by the fact that there is an affinity between the coating and the oil, rather than them being antagonistic. It is therefore not surprising to observe a poor epilame effect with oil No. 3.

[0120] However, the epilame effect is demonstrated and confirmed by Synth-A-Lube 9010 watch oil. Although the target values ​​were not achieved before the initial washes, contact angles of 50° and above (except for sapphire) indicate the presence of some oleophobicity. Furthermore, after three washes, the target value of 45° was reached for all substrates, indicating good wash resistance and therefore good adhesion of the non-halogenated coating to each substrate.

Claims

DEMANDS 1. A watchmaking process for oleophobic and hydrophobic, non-halogenated, and atmospheric-pressure cold plasma washing-resistant coating of at least a portion of a substrate surface, the process comprising the steps of: - Activation of a first carrier gas by a first electrical discharge, thus creating a first jet of plasma gas having an overall temperature equal to or less than 200 °C; - Introduction of an anchoring compound into said first jet of plasma gas, thereby activating the anchoring compound; - Bringing at least a part of said surface of said substrate into contact with said first jet of plasma gas comprising said activated anchoring compound, thus adhering the anchoring compound to said surface; - Activation of a second carrier gas by a second electrical discharge, thus creating a second jet of plasma gas having an overall temperature equal to or less than 200 °C; - Introduction of an epilamage compound into said second jet of plasma gas, thereby activating the epilamage compound; and - Contacting said part of said surface of said substrate to which the anchoring compound is adhered with said second jet of plasma gas comprising said activated epilamage compound, thereby adhering the epilamage compound to said anchoring compound and thus forming an oleophobic and hydrophobic, non-halogenated epilame coating resistant to watch washing on said part of said surface of said substrate; characterized in that the anchoring compound is according to the formula (I) Si(OR)xR"y(R'NH2)4-xy (I), where R and R”, identical or different, are H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, R', identical or different, is H, an alkyl group in C1-C10 optionally comprising an amine group, or an alkenyl group in C2-C10 optionally comprising an amine group, x is 1, 2 or 3, preferably 3, and y is 0 or 1, in which x + y is 0, 1, 2 or 3, And - the epilamage compound is according to formula (II) or according to formula (III): R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 , identical or different, are H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, preferably methyl or ethyl, and n is between 0 and 10, preferably between 0 and 6, more preferably between 0 and 4, in which at least one of R1, R2 or R3 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl, and at least one of R4, R5 or R6 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl; Or R 9 , R 10 , R 11, R 12 , R 13 and R 14 , identical or different, are H, an alkyl group in C1-C10, or an alkenyl group in C2-C10, preferably methyl or ethyl, m is between 1 and 10, preferably between 1 and 6, more preferably between 1 and 4, in which at least one, and preferably at least two, of R 9 , R 10 , R 11 , R 12 , R 13 and R 14 is a C1-C10 alkyl group, or a C2-C10 alkenyl group, preferably methyl or ethyl.

2. The hair removal process according to claim 1, characterized in that the hair removal compound according to formula (II) is tetramethyldisiloxane, hexamethyldisiloxane, or a combination thereof.

3. The hair removal process according to any one of the preceding claims, characterized in that the anchoring compound is (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, or a combination thereof.

4. The depilation process according to any one of the preceding claims, characterized in that the overall temperature of said plasma gas jet is equal to or less than 100 °C, preferably equal to or less than 50 °C.

5. The depilation process according to any one of the preceding claims, characterized in that the anchoring compound is introduced into said first plasma gas jet and / or the depilation compound is introduced into said second plasma gas jet in the form of an aerosol.

6. The hair removal process according to any one of the preceding claims, characterized in that said first carrier gas and said second carrier gas, identical or different, are an inert gas, preferably nitrogen and / or argon.

7. The depilation process according to any one of the preceding claims, characterized in that said substrate and said first jet of plasma gas comprising the activated anchoring compound are displaced relative to each other during said contact and / or in that said substrate and said second jet of plasma gas comprising the depilation compound are displaced relative to each other during said contact.

8. The epilamage process according to claim 7, characterized in that said substrate and said first jet of plasma gas comprising the activated anchoring compound are displaced relative to each other and that said at least a part of said surface is brought into contact with said first jet of plasma gas comprising the anchoring compound in several passes.

9. The de-epilating process according to any one of claims 7 and 8, characterized in that said substrate and said second jet of plasma gas comprising the de-epilating compound are displaced relative to each other and said part of said surface to which the anchoring compound is adhered is brought into contact with said second jet of plasma gas comprising the de-epilating compound in several passes.

10. The epilaming process according to any one of the preceding claims, characterized in that the first jet of plasma gas comprising the anchoring compound is generated in a plasma discharge chamber, and that said at least a part of said surface of said substrate is brought into contact with a residual plasma from the first jet of plasma gas comprising the anchoring compound from the plasma discharge chamber, and / or in that the second jet of plasma gas comprising the epilaming compound is generated in a plasma discharge chamber, and that said at least a part of said surface of said substrate is brought into contact with a residual plasma from the second jet of plasma gas comprising the epilaming compound from the plasma discharge chamber.

11. The epilamage process according to any one of the preceding claims, characterized in that said first carrier gas has a first flow rate and said anchoring compound is introduced into said first plasma gas at an anchoring flow rate, and that the ratio of the first flow rate to the anchoring flow rate is between 10:1 and 250:1, preferably between 25:1 and 200:1, more preferably between 50:1 and 100:

1.

12. The epilamage process according to any one of the preceding claims, characterized in that said second carrier gas has a second flow rate and said epilamage compound is introduced into said second plasma gas at an epilamage flow rate, and that the ratio of the second flow rate to the epilamage flow rate is between 10:1 and 250:1, preferably between 25:1 and 200:1, more preferably between 50:1 and 100:

1.

13. The de-piling process according to any one of the preceding claims, further comprising a step of preparing said surface of said substrate before contact with the plasma gas jet comprising said activated anchoring compound.

14. The depilation process according to any one of the preceding claims, characterized in that said surface of said substrate, at least a part of which is subjected to the depilation process, is made of a material selected from the group comprising metals, metal oxides, polymers, sapphire, ruby, silicon, silicon oxides, silicon nitrides, silicon carbides, diamond-like carbon (DLC), and their alloys, preferably NiP.

15. The depilation process according to any one of the preceding claims, characterized in that said substrate is a watch or jewelry item.

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