Method for depositing a visible light absorbing coating on a substrate

Abstract

One aspect of the invention relates to a method of depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), such as a watch component, said deposition method (100) being characterized in that it comprises: a first step (110) of providing a substrate (1); a second step (120) of depositing a sub-layer (21) covering at least a portion of the substrate (1) by the application of a first liquid mixture comprising a binder, a solvent and pigments whose average size (d90) is of nanometric dimension, the sub-layer (21) being formed by evaporation of said solvent; a third step (130) of depositing a stack (25) of a plurality of layers (22, 23, 24) with different particle sizes between each layer (n) of the stack (25) by the successive application of a plurality of liquid mixtures comprising a binder, a solvent and pigments with different particle sizes;each layer of the stack (25) being formed by evaporation of the solvent and each layer (n) at least partially covering a previous layer (n-1).;

Description

Technical field of the invention

[0001] The field of the invention relates to surface treatments of articles, such as decorative articles or watch components.

[0002] The invention relates more particularly to a method of depositing a decorative coating which has the optical characteristic of absorbing visible light.

[0003] The invention also relates to an article, for example a watch component, coated with such a decorative coating absorbing visible light.

[0004] The invention finds a particularly interesting application in the field of watchmaking, for the decoration of articles or components used in timepieces, for example plates, bridges, cogs, screws, oscillating masses, dials, indexes, appliques, window discs, hands or any other component of the movement or external casing of a timepiece. Technological background

[0005] There are visible light absorbing coatings that have a light absorption greater than 99.8%.

[0006] A well-known coating is Vantablack ®, which is based on carbon nanotubes oriented perpendicular to the substrate surface and packed tightly together. This coating produces a black color with an absorption coefficient of 99.965% of visible light.

[0007] However, such a coating based on carbon nanotubes is very expensive and presents health risks, as these particles are recognized as carcinogenic, mutagenic or reprotoxic.

[0008] Musou ® acrylic paint is also known, which is easier to use and apply and has an absorption of up to 99.4% of visible light and a clarity component L* close to 10. However, this coating has the particularity of being very fragile and light contact with the coating can easily cause the coating to peel or its absorption to deteriorate. For example, it is very complicated to clean this type of coating without damaging its aesthetic appearance if dust or a fiber has settled on it. Such a paint is not easily applicable, for example, in the watchmaking field.

[0009] Therefore, there is a need to improve these visible light absorbing coatings, allowing their use on items that can be handled, such as watch components, without risk to health and without the risk of degradation of the coating by simple contact or handling of the item. Summary of the invention

[0010] In this context, the invention aims to propose an article comprising a coating with very high light absorption while avoiding the use of carbon nanotubes and / or graphene particles.

[0011] To this end, the invention relates to a method of depositing a visible light-absorbing coating on a substrate for the formation of an article, such as a watch component, said deposition method being characterized in that it comprises: a first step of providing a substrate; a second step of depositing a sub-layer covering at least a portion of the substrate by applying a first liquid mixture comprising a binder, a solvent and pigments whose average size (d90) is of nanometric dimension, the sub-layer being formed by evaporation of said solvent; a third step of depositing a stack of a plurality of layers with different particle sizes between each layer (n) of the stack by successively applying a plurality of liquid mixtures comprising a binder, a solvent and pigments with different particle sizes; each layer of the stack being formed by evaporation of the solvent and each layer (n) at least partially covering a previous layer (n-1).

[0012] According to the invention, one of the aims of the invention is to propose a method for depositing a decorative coating absorbing visible light, which is easy to implement and makes it possible to obtain surface coatings with a clarity component L* of less than 20 with substrates of various types.

[0013] Preferably, the first liquid mixture forming the undercoat of the coating comprises between 5 and 10% by mass of pigments.

[0014] Preferably, the third step of depositing a stack of a plurality of layers is carried out by the successive application of a plurality of liquid mixtures, each liquid mixture for the formation of the plurality of layers of the stack comprising a binder, a solvent and pigments whose average size (d90) increases between each successive deposit of the layers forming the stack.

[0015] Preferably, each layer (n) of the plurality of layers of the stack has pigments whose average size (d90) corresponds to n*k / 10 µm, where k is a homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack.

[0016] Preferably, the third step of depositing a stack of a plurality of layers is carried out by the successive application of a plurality of liquid mixtures, each liquid mixture for the formation of the plurality of layers of the stack comprising a binder, a solvent and pigments whose average size (d90) increases between each successive deposition of layers of the stack, and whose proportion by mass of pigments in each liquid mixture decreases as the average size (d90) of the pigments increases.

[0017] Preferably, the plurality of liquid mixtures for the formation of the plurality of layers of the stack comprises between 0.5 and 10% by mass of pigments.

[0018] Preferably, the third step of depositing a stack comprises a first sub-step of depositing a first stacking layer from a liquid mixture comprising between 0.5 and 10% by mass of pigments in the mixture, the pigments having an average size (d90) corresponding to k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack.

[0019] Preferably, the liquid mixture for depositing the first layer of the stack comprises between 4 and 10% by mass of pigments, preferably between 4 and 8% by mass of pigments.

[0020] Preferably, the third step of depositing a stack comprises a second sub-step of depositing a second stacking layer from a liquid mixture comprising between 0.5 and 10% by mass of pigments in the mixture, the pigments having an average size (d90) corresponding to 2 k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack.

[0021] Preferably, the liquid mixture for depositing the second layer of the stack comprises between 1 and 4% by mass of pigments.

[0022] Preferably, the third step of depositing a stack comprises a third sub-step of depositing a third stacking layer from a liquid mixture comprising between 0.5 and 10% by mass of pigments in the mixture, the pigments having an average size (d90) corresponding to 3 k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack.

[0023] Preferably, the liquid mixture for depositing the third layer of the stack comprises between 0.5 and 4% by mass of pigments, preferably between 0.5 and 1% by mass of pigments.

[0024] Preferably, the underlayer and / or the plurality of layers of the stack are deposited by spraying, by spraying, by dipping, by screen printing, by printing or even by pad printing.

[0025] Preferably, the first liquid mixture forming the underlayer of the coating and / or the plurality of liquid mixtures forming the plurality of layers of the stack are composed of a binder, a solvent, pigments, optionally a matting agent, glass beads and / or a dispersing agent.

[0026] Preferably, the binder is a polymer.

[0027] Preferably, the binder is an acrylic, an epoxy polymer or even a polyurethane.

[0028] Preferably, the first liquid mixture forming the underlayer of the coating and / or the plurality of liquid mixtures forming the plurality of layers of the stack are colored inks.

[0029] The invention also relates to an article comprising a substrate and a coating applied by the method according to the invention.

[0030] Such an article therefore has a light-absorbing surface coating with a clarity component L* less than 20.

[0031] Preferably, the article is a watch component.

[0032] The invention also relates to a timepiece comprising such a timepiece component. Brief description of the figures

[0033] The aims, advantages and characteristics of the present invention will appear on reading the detailed description below with reference to the following figures: there Figure 1 schematically illustrates a sectional view of an article, such as a watch component, comprising a substrate and a visible light absorbing coating according to the invention; Figure 2 illustrates the main successive steps of an exemplary embodiment of a method for depositing a visible light-absorbing coating on a substrate for producing an article, such as a watch component, according to the invention; Figure 3 illustrates an exemplary embodiment of an article according to the invention. Detailed description of the invention

[0034] In the present description, the colorimetric properties of the light-absorbing coating obtained according to the method of depositing a coating according to the invention are expressed using the CIE L*a*b* color space and measured according to the CIE 1976 standard on polished samples with a KONICA MINOLTA CM-3610-A spectrophotometer, with the following parameters: CIE D65 illumination source (daylight 6500°K), 10° tilt, SCI measurements (specular reflection included), 4 mm diameter measuring area.

[0035] A CIELAB color space (compliant with CIE standards No. 15, ISO 7724 / 1, DIN 5033 Teil 7, ASTM E-1164) has a lightness component L*, representative of the way in which the material reflects light, similar to lightness, with an a* component which is the green / red component and a b* component which is the blue / yellow component.

[0036] In the present application, the average size of the particles and pigments is characterized with respect to the d90 value of a particle size distribution.

[0037] There Figure 1 schematically illustrates a sectional view of an article 10, such as a watch component, comprising a substrate 1 and a visible light-absorbing coating 20 covering at least a portion of the substrate 1 by means of the deposition method 100 according to the invention. Such a light-absorbing coating 20 according to the invention forms a multilayer structure composed of pigments with a variable particle size between the layers, preferably increasing with the increase in the number of layers.

[0038] Preferably, the density of the pigments between the different layers of the coating 20 is also variable, preferably decreasing with the increase in the number of layers.

[0039] Article 10 is for example a watch component, for example a plate, a bridge, a wheel, a screw, an oscillating weight, a dial, an index, an applique, a window disc, a hand or any other component or organ of a watch movement or of a component of a timepiece to which one wishes to give an impression of deep and intense color, without light reflection, with a clarity component L* less than 20.

[0040] There Figure 3 illustrates a timepiece 200 comprising an item 10 according to the invention. In this exemplary embodiment, the item 10 according to the invention is a dial.

[0041] The substrate 1 may be of a variable nature, for example made of metallic material, polymer material or even ceramic material, or even composite material.

[0042] Using the method according to the invention, it is possible to obtain an article 10 with a coating 20 whose clarity component L* is less than 20 with various substrates. For comparison, a coating method using physical vapor deposition (PVD) does not allow a coating to be obtained with a clarity component L* less than 20 due to the topology of the deposited layers. With PVD deposition, the clarity component L* of a matte coating is between 25 and 30.

[0043] The particular multi-layer structure of the light-absorbing coating 20 according to the invention makes it possible to avoid reflection phenomena with the visible surface of the coating. The coating 20 also makes it possible to diffuse the light in the structure created by the differences in particle size of the pigments that make up the coating until it is trapped, so as to obtain maximum absorption of the light.

[0044] The coating 20 comprises an underlayer 21 forming a base layer, configured to cover the substrate 1, at least over a portion of the substrate 1.

[0045] Preferably, the underlayer 21 completely covers at least one surface of the substrate 1.

[0046] The sub-layer 21 has a sufficient thickness so that it is homogeneous and opaque and so that the optical disturbance of the substrate 1 is no longer active. The sub-layer 21 has, for example, a thickness equal to or greater than 1 µm and less than 20 µm, and more preferably a thickness of between 5 µm and 10 µm.

[0047] Preferably, the underlayer 21 is formed by the deposition on the substrate 1 of a first liquid mixture comprising a binder, pigments, and a solvent.

[0048] For example, the undercoat is formed by depositing a first liquid mixture comprising, by mass, 30 to 40% binder, 50 to 60% solvent and 5 to 10% pigments.

[0049] For example, the undercoat is formed by depositing a first liquid mixture consisting, by mass, of 30% acrylic binder, 60% solvents and 10% Emperor ® carbon black pigments < 1600.

[0050] Optionally, the first liquid mixture may also include a matting agent, for example a nanosilica, to further accentuate the intensity of the coating 20.

[0051] Optionally, the first liquid mixture may also include a dispersing agent facilitating the suspension of the pigments in the liquid mixture.

[0052] Preferably, the binder of the first liquid mixture forming the underlayer 21 is a polymer, for example an acrylic, an epoxy polymer or even a polyurethane.

[0053] For example, the first liquid mixture is a colored ink.

[0054] For example, the first liquid mixture is a black ink with carbon black pigments.

[0055] The first liquid mixture is, for example, applied by spraying, by dipping, by screen printing, by printing or by pad printing on the substrate 1.

[0056] Once the liquid mixture is applied to the substrate 1, the solvent evaporates, the binder shrinks around the pigments thus creating the underlayer 21 of the coating 20.

[0057] Preferably, the pigments of the underlayer 21 have an average size (d90) of nanometric dimension, for example between 20 and 120 nm, preferably less than 100 nm. Thus, the underlayer 21 is a homogeneous layer with low roughness.

[0058] The underlayer 21 is covered by a stack 25 of several layers 22, 23, 24 superimposed on each other, each layer of the stack 25 having pigments whose average size (d90) is different from the average size of the pigments of the layer that it covers.

[0059] Preferably, the stack 25 has pigments distributed according to an average size (d90) increasing from the substrate towards the surface of the coating 20. Thus, each layer of the stack 25 has pigments with an average size (d90) greater than the average size of the pigments of the layer that it covers.

[0060] Preferably, each layer n of the stack 25 has pigments whose average size (d90) is equivalent to n * k / 10 µm, where k is a homothety factor between the average size (d90) of the pigments of the layer (n-1) previously deposited and the average size (d90) of the pigments of the layer (n) to be deposited, i.e. between two consecutive layers of the stack 25.

[0061] Preferably the homothety factor is between 5 and 1000.

[0062] In the embodiment shown in the Figure 1 , the stack 25 comprises three layers 22, 23, 24 deposited successively. Of course, the stack 25 can comprise at least two successive layers or more than three successive layers to form the particular structure of the stack 25 covering the sub-layer 21.

[0063] The first layer 22 of the stack 25 comprises pigments whose average size (d90) is greater than the average size of the pigments of the sub-layer 21, for example of micrometric size and less than 20 µm, preferably of the order of 15 µm.

[0064] The second layer 23 of the stack 25 at least partially covering the first layer 22 of the stack 25 comprises pigments whose average size (d90) is for example of the order of 80 µm. The third layer 24 of the stack 25 at least partially covering the second layer 23 of the stack 25 comprises pigments whose average size (d90) is for example of the order of 250 µm.

[0065] Each layer 22, 23, 24 is formed respectively by successive deposition of a liquid mixture comprising a binder, pigments, and a solvent, the average size (d90) of the pigments of the different liquid mixtures varying according to the ratio mentioned previously to form the different layers with an increasing granulometry, so as to increase the roughness of each layer deposited compared to the previous layer.

[0066] After application of each mixture by spraying, by spraying, by dipping, by screen printing, by printing or even by pad printing, the solvent evaporates to allow polymerization and retraction of the binder around the pigments thus forming a solid layer at least partially covering the previous layer or the underlayer 21, the new layer having a roughness greater than the previous layer.

[0067] Preferably, the binder, the nature of the pigments, and the solvent used for the formation of the liquid mixtures for the purpose of depositing the different layers 22, 23, 24 of the stack 25 are identical.

[0068] Optionally, the liquid mixtures for forming the stack 25 may comprise a matting agent, for example a nanosilica, to further accentuate the intensity of the stack 25 and more generally of the coating 20.

[0069] Optionally, the liquid mixtures for forming the stack 25 may comprise a dispersing agent facilitating the suspension of the pigments in the first liquid mixture.

[0070] Optionally, the liquid mixtures for forming the stack 25 may include glass beads to further increase the roughness of the stack. Preferably, the glass beads are used in the last layer of the stack 25.

[0071] Preferably, the binder of the liquid mixtures forming the stack 25 is a polymer, for example an acrylic, an epoxy polymer or even a polyurethane.

[0072] For example, the liquid mixtures forming stack 25 are colored inks.

[0073] Preferably, the binder and the solvent used for the formation of the layers of the stack 25 are identical to those used for the production of the sub-layer 21. The pigments used for the formation of the layers of the stack 25 may be of the same nature as or different from the pigments used for the production of the sub-layer 21.

[0074] Preferably, the proportion of pigments in the liquid mixtures forming the different layers 22, 23, 24 of the stack 25 is between 0.5% and 10% by mass. Preferably, the proportion of pigments in the liquid mixture is higher when the average size (d90) of the pigments is smaller. Thus, the density of the pigments in the layers 22, 23, 24 of the stack 25 is increasingly lower as the average size (d90) of the pigments increases.

[0075] For example, the first layer 22 of the stack 25 is produced from a liquid mixture comprising between 4 and 10% by mass of pigments, preferably between 4 and 8% by mass of pigments.

[0076] For example, the second layer 23 of the stack 25 is made from a liquid mixture comprising between 1 and 4% by mass of pigments.

[0077] For example, the third layer 24 of the stack 25 is produced from a liquid mixture comprising between 0.5 and 4% by mass of pigments, preferably between 0.5 and 1% by mass.

[0078] There Figure 2 illustrates the main steps of the method 100 for depositing a coating 20 absorbing visible light on a substrate 1 according to the invention.

[0079] The deposition method 100 according to the invention comprises a first step 110 of providing a substrate 1.

[0080] The deposition method 100 according to the invention comprises a second step 120 of deposition of a sub-layer 21, or base layer, covering at least a portion of the substrate 1. This second deposition step 120 is carried out by spraying, by spraying, by dipping, by screen printing, by printing or even by pad printing of a first liquid mixture comprising a binder, a solvent and between 5 and 10% by mass of pigments of an average size (d90) of nanometric dimension, for example less than 100 nm.

[0081] This step 120 of depositing a sub-layer 21 comprises a sub-step of evaporation of the solvent of the liquid mixture applied to the substrate 1 so that the binder shrinks around the pigments to form the sub-layer 21 of the coating 20.

[0082] The deposition method 100 also comprises a third step 130 of deposition of a stack 25 of a plurality of superimposed layers 22, 23, 24 with different particle sizes between each layer of the stack 25.

[0083] This third step 130 comprises a first sub-step 131 of depositing a first layer 22 of the stack 25 from a liquid mixture comprising a binder, a solvent and between 0.5 and 10% by mass of pigments with an average size (d90) greater than 100 nm and equivalent to k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of two consecutive layers of stack 25.

[0084] Preferably, the liquid mixture for depositing the first layer 22 comprises between 4 and 10% by mass of pigments.

[0085] Preferably, the liquid mixture for depositing the first layer 22 comprises between 4 and 8% by mass of pigments.

[0086] This first sub-step 131 is carried out by spraying, by spraying, by dipping, by screen printing, by printing or even by pad printing.

[0087] This first sub-step 131 comprises a step of evaporation of the solvent of the liquid mixture applied to the underlayer 21 so that the binder shrinks around the pigments to form the first layer 22 of the coating 20, superimposed on the underlayer 21.

[0088] The third step 130 comprises a second sub-step 132 of depositing a second layer 23 of the stack 25 from a liquid mixture comprising a binder, a solvent and between 0.5 and 10% by mass of pigments of an average size (d90) equivalent to 2 k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of the first layer 22 and the average size (d90) of the pigments of the second layer 23.

[0089] Preferably, the liquid mixture for depositing the second layer 23 comprises between 1 and 4% by mass of pigments.

[0090] This second sub-step 132 is carried out by spraying, by spraying, by dipping, by screen printing, by printing or even by pad printing.

[0091] This second sub-step 132 comprises a step of evaporation of the solvent of the liquid mixture applied to the first layer 22 so that the binder shrinks around the pigments to form the second layer 23 of the coating 20, superimposed on the first layer 22.

[0092] The third step 130 comprises a third sub-step 133 of depositing a third layer 24 of the stack 25 from a liquid mixture comprising a binder, a solvent and between 0.5 and 10% by mass of pigments of an average size (d90) equivalent to 3 k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of the second layer 23 and the average size (d90) of the pigments of the third layer 24.

[0093] Preferably, the liquid mixture for depositing the third layer 24 comprises between 0.5 and 4% by mass of pigments.

[0094] Preferably, the liquid mixture for depositing the third layer 24 comprises between 0.5 and 1% by mass of pigments.

[0095] This third sub-step 133 is carried out by spraying, by spraying, by dipping, by screen printing, by printing or even by pad printing.

[0096] This third sub-step 133 comprises a step of evaporation of the solvent of the liquid mixture applied to the second layer 22 so that the binder shrinks around the pigments to form the third layer 24 of the coating 20, superimposed on the second layer 23.

[0097] Of course, the deposition method 100 can comprise other sub-steps of deposition of additional layers depending on the number of layers desired in the stack 25 of the coating 20.

[0098] According to a first exemplary embodiment of the invention, a brass substrate is used, for example for the formation of a dial, on which a light-absorbing coating according to the invention is applied.

[0099] The brass substrate, for example, has a thickness of 0.27 mm.

[0100] Undercoat 21 is applied to the brass substrate by dipping from a first liquid mixture consisting of 2 g of polyurethane resin (Berlacryl), 0.5 g of Emperor 1600 carbon black pigments and 2.8 g of Berlaflex thinner. The layer is left to dry for 20 minutes to allow the thinner to evaporate.

[0101] The first layer 22 of the stack 25 is applied to the undercoat 21 by dipping from a second liquid mixture consisting of 2 g of polyurethane resin (Berlacryl), 0.3 g of Living Ink pigments and 3.5 g of Berlaflex diluent. The layer is left to dry for 20 minutes to allow the diluent to evaporate.

[0102] The second layer 23 of the stack 25 is applied to the first layer 22 by dipping from a third liquid mixture consisting of 2 g of polyurethane resin (Berlacryl), 0.2 g of Norit A ultra E153 pigments and 4 g of Berlaflex diluent. The layer is left to dry for 20 minutes to allow the diluent to evaporate.

[0103] The third layer 24 of the stack 25 is applied to the second layer 23 by dipping from a fourth liquid mixture consisting of 2 g of polyurethane resin (Berlacryl), 0.2 g of Norit SX super E153 carbon pigments, 1.5 g of 90-150 µm glass beads and 4 g of Berlaflex diluent. The layer is left to dry for 20 minutes to allow the diluent to evaporate.

[0104] With such a coating, a brass dial with a black surface coating with a clarity component L* of 15.9 is obtained.

Claims

1. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), such as a watch component, said deposition method (100) being characterized in thatit comprises: - a first step (110) of providing a substrate (1); - a second step (120) of depositing a sub-layer (21) covering at least a portion of the substrate (1) by applying a first liquid mixture comprising a binder, a solvent and pigments whose average size (d90) is of nanometric dimension, the sub-layer (21) being formed by evaporation of said solvent; - a third step (130) of depositing a stack (25) of a plurality of layers (22, 23, 24) with different particle sizes between each layer (n) of the stack (25) by successively applying a plurality of liquid mixtures comprising a binder, a solvent and pigments with different particle sizes; each layer of the stack (25) being formed by evaporation of the solvent and each layer (n) at least partially covering a previous layer (n-1).

2. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to the preceding claim. characterized in that the first liquid mixture forming the undercoat (21) of the coating (20) comprises between 5 and 10% by mass of pigments.

3. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that the third step (130) of depositing a stack (25) of a plurality of layers (22, 23, 24) is carried out by the successive application of a plurality of liquid mixtures, each liquid mixture for the formation of the plurality of layers (22, 23, 24) of the stack (25) comprising a binder, a solvent and pigments whose average size (d90) increases between each successive deposit of the layers forming the stack (25).

4. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that each layer (n) of the plurality of layers (22, 23, 24) of the stack (25) has pigments whose average size (d90) corresponds to n*k / 10 µm, where k is a homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack (25).

5. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in thatthe third step (130) of depositing a stack (25) of a plurality of layers (22, 23, 24) is carried out by the successive application of a plurality of liquid mixtures, each liquid mixture for the formation of the plurality of layers (22, 23, 24) of the stack (25) comprising a binder, a solvent and pigments whose average size (d90) increases between each successive deposition of layers of the stack (25), and whose proportion by mass of pigments in each liquid mixture decreases as the average size (d90) of the pigments increases.

6. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to the preceding claim. characterized in that the plurality of liquid mixtures for forming the plurality of layers (22, 23, 24) of the stack (25) comprises between 0.5 and 10% by mass of pigments.

7. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that the third step (130) of depositing a stack (25) comprises a first sub-step (131) of depositing a first layer (22) of stack (25) from a liquid mixture comprising between 0.5 and 10% by mass of pigments in the mixture, the pigments having an average size (d90) corresponding to k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack (25).

8. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to the preceding claim. characterized in that the liquid mixture for depositing the first layer (22) of the stack (25) comprises between 4 and 10% by mass of pigments.

9. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that the third step (130) of depositing a stack (25) comprises a second sub-step (132) of depositing a second layer (22) of stack (25) from a liquid mixture comprising between 0.5 and 10% by mass of pigments in the mixture, the pigments having an average size (d90) corresponding to 2 k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack (25).

10. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to the preceding claim. characterized in that the liquid mixture for depositing the second layer (23) of the stack (25) comprises between 1 and 4% by mass of pigments.

11. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that the third step (130) of depositing a stack (25) comprises a third sub-step (133) of depositing a third layer (22) of stack (25) from a liquid mixture comprising between 0.5 and 10% by mass of pigments in the mixture, the pigments having an average size (d90) corresponding to 3 k / 10 µm, with k the homothety factor between the average size (d90) of the pigments of two consecutive layers of the stack (25).

12. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to the preceding claim. characterized in that the liquid mixture for depositing the third layer (24) of the stack (25) comprises between 0.5 and 4% by mass of pigments.

13. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that the underlayer (21) and / or the plurality of layers (22, 23, 24) of the stack (25) are deposited by spraying, by spraying, by dipping, by screen printing, by printing or even by pad printing.

14. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that the first liquid mixture forming the underlayer (21) of the coating (20) and / or the plurality of liquid mixtures forming the plurality of layers (22, 23, 24) of the stack (25) are composed of a binder, a solvent, pigments, optionally a matting agent, glass beads and / or a dispersing agent.

15. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to the preceding claim. characterized in that the binder is a polymer.

16. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to the preceding claim. characterized in that the binder is an acrylic, an epoxy polymer or even a polyurethane.

17. Method for depositing (100) on a substrate (1) a coating (20) absorbing visible light for the formation of an article (10), according to one of the preceding claims. characterized in that the first liquid mixture forming the underlayer (21) of the coating (20) and / or the plurality of liquid mixtures forming the plurality of layers (22, 23, 24) of the stack (25) are colored inks.

18. Article (10) characterized in thatit comprises a substrate (1) and a light-absorbing coating (20) deposited by the deposition method according to one of claims 1 to 17, the coating (20) having a clarity component L* of less than 20.

19. Article (10) according to the preceding claim characterized in that Article (20) is a watch component.

20. Timepiece (200) comprising a timepiece component (10) according to claim 19.

Images