Method for accumulating visible light absorptive coating on base material

Abstract

To provide a method for accumulating a coating having high light absorptivity on a base material while avoiding the use of a carbon nanotube and / or graphene particles, and an article including the coating.SOLUTION: There is provided a method for accumulating a coating 20 absorbing visible light for forming an article 10 such as a component of a portable timepiece on a base material 1. The method includes a first step of preparing a base material, a second step of accumulating a first liquid mixture containing a binder, a solvent and a pigment having a d90 value having a size of a nanometer level and coating at least a part of the base material, and accumulating a substrate layer 21 formed by evaporating the solvent, and a third step of sequentially accumulating a mixture of a plurality of types of liquids containing the binder, the solvent and pigments having different particle sizes, and thereby accumulating a laminate 25 of a plurality of layers 22, 23 and 24, where the particle sizes between respective layers n of the laminate are different, and each of the layers of the laminate is formed by evaporating the solvent.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the field of surface treatment of articles such as components of ornaments and portable timepieces (e.g., wristwatches, pocket watches).

[0002] The present invention particularly relates to a method of depositing a decorative coating having optical properties that absorb visible light.

[0003] The present invention further relates to an article coated with a decorative coating that absorbs visible light as described above, such as a component of a portable timepiece.

[0004] The present invention has particularly interesting applications in the field of portable timepieces for the decoration of components used in articles and timepieces. Such articles and components include, for example, plates, bridges, gear trains, screws, balance weights, dials, indexes, decorations, aperture disks, hands, or any other arbitrary components of the movement and outer casing of a timepiece.

Background Art

[0005] There are coatings that absorb visible light and have a light absorption rate exceeding 99.8%.

[0006] In particular, a carbon nanotube-based Vantablack (registered trademark) coating that is oriented perpendicular to the surface of the substrate and pressed against each other is known. Such a coating gives a black color with an absorption coefficient of 99.965% in visible light.

[0007] However, carbon nanotube-based coatings are very expensive and pose health risks. This is because such particles are known to have carcinogenic, mutagenic, or reproductive toxicity.

[0008] The Musou (registered trademark) acrylic paint, which is easy to use and apply, is also known to have a maximum absorption rate of 99.4% for visible light and a luminance component L* close to 10. However, this coating has the characteristic of being very fragile, and just lightly touching this coating can easily cause the coating to peel off or the absorption rate to decrease. For example, when dust or fibers are deposited, it is very difficult to clean this type of coating without damaging its aesthetic appearance. Such paints are not easily available in the portable watch industry and the like.

[0009] As a result, it is necessary to improve such visible light-absorbing coatings so that they can be used for articles such as components of portable watches, without any risk to health and without the risk of the coating being damaged by simple contact or handling of the article.

Summary of the Invention

Problems to be Solved by the Invention

[0010] In view of such a situation, an object of the present invention is to provide an article including a coating having a very high light absorption rate while avoiding the use of carbon nanotubes and / or graphene particles.

Means for Solving the Problems

[0011] For this purpose, the present invention relates to a method of depositing a coating that absorbs visible light on a substrate to form an article such as a component of a portable watch, the method comprising: - A first step of preparing a substrate, and a second step of depositing an underlayer formed by covering at least a part of the substrate and evaporating the solvent by depositing a first liquid mixture including a binder, a solvent, and a pigment having a d90 value in the nanometer level dimension; - A third step of depositing a laminate of a plurality of layers by sequentially depositing a mixture of a plurality of types of liquids including a binder, a solvent, and pigments having different particle sizes. The particle sizes differ between each layer n of the laminate, each layer of the laminate is formed by evaporating the solvent, and each layer n at least partially covers the preceding layer n-1.

[0012] One of the objects of the present invention is to provide a method for depositing a decorative coating that absorbs visible light, is easy to mount, and enables a surface coating with a luminance component L* of less than 20 to be obtained on various types of substrates.

[0013] Preferably, the first liquid mixture for forming the underlayer of the coating contains 5 to 10% by weight of a pigment.

[0014] Preferably, the third step of depositing a laminate of a plurality of layers is performed by sequentially depositing a mixture of a plurality of types of liquids, and each liquid mixture for forming the plurality of layers of the laminate contains a binder, a solvent, and a pigment having an increasing d90 value for each sequential deposition of the layers forming the laminate.

[0015] Preferably, each layer (n) of the plurality of layers of the laminate contains a pigment having a d90 value corresponding to a value of n·k / 10 μm, where k is a similarity coefficient between the d90 values of the pigments in two consecutive layers of the laminate.

[0016] Preferably, the third step of depositing a laminate of a plurality of layers is performed by sequentially depositing a plurality of types of liquid mixtures, and each liquid mixture for forming the plurality of layers of the laminate contains a binder, a solvent, and a pigment having an increasing d90 value during the sequential deposition of the layers of the laminate, and the content by weight of the pigment in each liquid mixture decreases as the d90 value of the pigment increases.

[0017] Preferably, the plurality of types of liquid mixtures for forming the plurality of layers of the laminate contain 0.5 to 10% by weight of a pigment.

[0018] Preferably, the third step of depositing the laminate comprises a first sub-step of depositing the first layer of the laminate with a liquid mixture containing 0.5 to 10% by weight of a pigment having a d90 value corresponding to k / 10 μm, where k is the similarity coefficient between the d90 values of the pigment in two consecutive layers of the laminate.

[0019] Preferably, the liquid mixture for depositing the first layer of the laminate contains 4 to 10% by weight, preferably 4 to 8% by weight, of a pigment.

[0020] Preferably, the third step of depositing the laminate comprises a second sub-step of depositing the second layer of the laminate with a liquid mixture containing 0.5 to 10% by weight of a pigment having a d90 value corresponding to 2k / 10 μm, where k is the similarity coefficient between the d90 values of the pigment in two consecutive layers of the laminate.

[0021] Preferably, the liquid mixture for depositing the second layer of the laminate contains 1 to 4% by weight of a pigment.

[0022] Preferably, the third step of depositing the laminate comprises a third sub-step of depositing the third layer of the laminate with a liquid mixture containing 0.5 to 10% by weight of a pigment having a d90 value corresponding to 3k / 10 μm, where k is the similarity coefficient between the d90 values of the pigment in two consecutive layers of the laminate.

[0023] Preferably, the liquid mixture for depositing the third layer of the laminate contains 0.5 to 4% by weight, preferably 0.5 to 1% by weight, of a pigment.

[0024] Preferably, the base layer and / or the plurality of layers of the laminate are deposited by spraying, dipping, screen printing, printing or pad printing.

[0025] Preferably, the first liquid mixture for forming the base layer of the coating, and / or the mixture of the plurality of types of liquids for forming the plurality of layers of the laminate, includes a binder, a solvent, and a pigment, and further optionally includes a matting agent, glass microspheres, and / or a dispersant.

[0026] Preferably, the binder is made of a polymer.

[0027] Preferably, the binder is made of acrylic, epoxy polymer or polyurethane.

[0028] Preferably, the first liquid mixture for forming the base layer of the coating, and / or the mixture of the plurality of types of liquids for forming the plurality of layers of the laminate, is a colored ink.

[0029] The present invention further relates to an article comprising a substrate and a coating deposited by the method according to the present invention.

[0030] Therefore, such an article includes a light-absorbing surface coating with a luminance component L* of less than 20.

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

[0032] The present invention further relates to a timepiece comprising such a component of a portable watch.

[0033] The objects, advantages and features of the present invention will become apparent by reading the following detailed description with reference to the drawings.

Brief Description of the Drawings

[0034]

Figure 1

Figure 2

Figure 3

DETAILED DESCRIPTION OF THE INVENTION

[0035] In this specification, the colorimetric properties of the light-absorbing coating obtained according to the method of depositing the coating according to the present invention are represented using the CIE L*a*b* color space, and for the polished sample, using a KONICA MINOLTA CM-3610-A spectrophotometer, the following parameters are used and measured according to the CIE 1976 standard. That is, the illumination source is CIE D65 (daylight 6500K), 10° inclination, SCI measurement (including specular reflection), and the measurement area is 4 mm in diameter.

[0036] The CIELAB color space (conforming to CIE Standard No. 15, ISO 7724 / 1, DIN 5033 Teil 7, ASTM E-1164) has a luminance component L* that represents the light reflectivity of the material, which is luminance, and in addition, there is an a* component that is the green / red component and an ab* component that is the blue / yellow component.

[0037] In this application, the sizes of the particles and pigments are characterized in relation to the d90 value of the particle size distribution. In the particle size distribution, the use of the d90 value means that at least 90% of the particles or pigments in the particle aggregate used are smaller than the given d90 value.

[0038] FIG. 1 schematically shows a cross-sectional view of an article 10, such as a component of a portable timepiece, including a substrate 1 and a visible light-absorbing coating 20 that covers at least a part of the substrate 1 using the deposition method 100 according to the present invention. Such a light-absorbing coating 20 according to the present invention preferably forms a multi-layer structure including pigments with different particle sizes between the layers such that the particle size increases as the number of layers increases.

[0039] Preferably, the density of the pigment between different layers of the coating 20 also varies, preferably decreasing as the number of layers increases.

[0040] The article 10 does not reflect light, has a luminance component L* of less than 20, and is, for example, a component of a portable timepiece that gives an impression of a deep and intense color, such as a movement for a portable timepiece or a component for a casing of a timepiece, a plate, a bridge, a wheel, a screw, a pendulum, a dial, an index, a decoration, an aperture disk, a hand, or any other component or mechanism.

[0041] Figure 3 shows a timepiece 200 including the article 10 according to the present invention. In this embodiment, the article 10 according to the present invention is a dial.

[0042] The substrate 1 can be made of any material, for example, it can be made of metal, polymer, ceramics, or composite material.

[0043] Thanks to the method according to the present invention, it is possible to obtain an article 10 including a coating 20 with a luminance component L* of less than 20 using various substrates. For comparison, in a physical vapor deposition (PVD) coating process, it is not possible to form a coating with a luminance component L* of less than 20 due to the topology of the deposited layer. In the case of PVD, the luminance component L* of a matte coating is 25 - 30.

[0044] Thanks to the specific multilayer structure of the light-absorbing coating 20 according to the present invention, it is possible to avoid the reflection phenomenon on the visible surface of this coating 20. Also, thanks to this coating 20, it is possible to diffuse light until it is captured in the structure formed by the difference in the particle size of the pigments constituting this coating 20, maximizing light absorption.

[0045] The coating 20 includes an underlayer 21 that forms a base layer configured to cover the substrate 1 over at least a part of the substrate 1.

[0046] Preferably, the underlayer 21 completely covers at least one surface of the substrate 1.

[0047] This underlayer 21 has a sufficient thickness to ensure that the underlayer 21 is homogeneous and opaque and that the optical disturbance of the substrate 1 is inactive. For example, the underlayer 21 has a thickness of 1 μm or more and less than 20 μm, and more preferably has a thickness of 5 μm to 10 μm.

[0048] Preferably, the underlayer 21 is formed by depositing a first liquid mixture containing a binder, a pigment, and a solvent on the substrate 1.

[0049] For example, the underlayer is formed by depositing a first liquid mixture containing 30 to 40% by weight of a binder, 50 to 60% by weight of a solvent, and 5 to 10% by weight of a pigment.

[0050] For example, the underlayer is formed by depositing a first liquid mixture containing 30% by weight of an acrylic binder, 60% by weight of a solvent, and 10% by weight of Emperor® 1600 carbon black pigment.

[0051] Optionally, the first liquid mixture can further contain a matting agent, such as nanosilica, to further enhance the strength of the coating 20.

[0052] Optionally, the first liquid mixture can further contain a dispersant that contributes to suspending the pigment in the liquid mixture.

[0053] Preferably, the binder in the first liquid mixture forming the underlayer 21 is made of a polymer, such as acrylic, epoxy polymer, or polyurethane.

[0054] For example, the first liquid mixture is a colored ink.

[0055] For example, the first liquid mixture is a black ink containing a carbon black pigment.

[0056] For example, the first liquid mixture is applied to the substrate 1 by spraying, dipping, screen printing, printing, or pad printing.

[0057] When the liquid mixture is applied to the substrate 1, the solvent evaporates and the binder shrinks around the pigment, thereby forming the underlayer 21 of the coating 20.

[0058] Preferably, the pigment in the underlayer 21 has a d90 value that is on the nanometer level of dimension, for example, 20 to 120 nm, and preferably less than 100 nm. Thus, the underlayer 21 is a homogeneous layer with low roughness.

[0059] The underlayer 21 is covered with a laminate 25 of several layers 22, 23, 24 that overlap each other, and the pigment contained in each layer of this laminate 25 has a d90 value that is different from the particle size of the pigment in the layer below it.

[0060] Preferably, the pigment contained in the laminate 25 is distributed such that the d90 value increases as it moves from the substrate side towards the surface of the coating 20. In this way, the pigment contained in each layer of the laminate 25 has a d90 value that is larger than the d90 value of the pigment in the layer below it.

[0061] Preferably, the pigment contained in each layer n of the laminate 25 has a d90 value of n·k / 10 μm. Here, k is the similarity coefficient between the d90 value of the pigment in the previously deposited layer (n - 1) and the d90 value of the pigment in the layer n to be deposited, that is, between two consecutive layers of the laminate 25.

[0062] Preferably, the similarity coefficient is 5 to 1000.

[0063] In the embodiment shown in FIG. 1, the laminate 25 includes three layers 22, 23, and 24 sequentially deposited. Of course, the laminate 25 can include at least two sequential layers to form a specific structure of the laminate 25 that covers the underlying layer 21, and can also include a number of sequential layers exceeding three.

[0064] The pigment contained in the first layer 22 of the laminate 25 has a d90 value that is greater than the d90 value of the pigment in the underlying layer 21, for example, at the micrometer level, less than 20 μm, preferably 15 μm or less.

[0065] The second layer 23 of the laminate 25 that at least partially covers the first layer 22 of the laminate 25 contains a pigment having a d90 value of, for example, 80 μm or less. The third layer 24 of the laminate 25 that at least partially covers the second layer 23 of the laminate 25 contains a pigment having a d90 value of, for example, 250 μm or less.

[0066] Each of the layers 22, 23, and 24 is formed by sequential deposition of a binder and a liquid mixture containing a pigment and a solvent, and the d90 value of the pigment in different liquid mixtures changes according to the ratio so as to form different layers with increasing particle size such that the roughness of each deposited layer is greater than that of the lower layer.

[0067] After applying each mixture by spraying, dipping, screen printing, printing, or pad printing, the solvent evaporates, enabling polymerization and shrinkage of the binder around the pigment, thereby forming a solid layer that at least partially covers the lower layer or the underlying layer 21, and the new layer is rougher than the lower layer.

[0068] Preferably, the properties of the binder, pigment, and solvent used to form the liquid mixture for depositing the various layers 22, 23, and 24 of the laminate 25 are the same.

[0069] Optionally, the liquid mixture for forming the laminate 25 can contain a matting agent, such as nanosilica, to further enhance the strength of the laminate 25, or more generally, the strength of the coating 20.

[0070] Optionally, the liquid mixture used to form the laminate 25 can contain a dispersant that contributes to suspending the pigment in the first liquid mixture.

[0071] Optionally, the liquid mixture for forming the laminate 25 can further contain glass frit to increase the roughness of the laminate. Preferably, the glass frit is used in the last layer of the laminate 25.

[0072] Preferably, the binder of the liquid mixture for forming the laminate 25 is a polymer, such as acrylic, epoxy polymer or polyurethane.

[0073] For example, the liquid mixture for forming the laminate 25 is a colored ink.

[0074] Preferably, the binder and solvent used to form the layers of the laminate 25 are the same as those used to form the underlying layer 21. The pigment used to form the layers of the laminate 25 may be the same as or different from the pigment used to form the underlying layer 21.

[0075] Preferably, the pigment content in the liquid mixture for forming the different layers 22, 23, 24 of the laminate 25 is 0.5 to 10% by weight. Preferably, the pigment content in the liquid mixture is increased as the d90 value of the pigment decreases. Therefore, the density of the pigment in the layers 22, 23, 24 of the laminate 25 decreases as the d90 value of the pigment increases.

[0076] For example, the first layer 22 of the laminate 25 is made from a liquid mixture containing 4 to 10% by weight, preferably 4 to 8% by weight, of pigment.

[0077] For example, the second layer 23 of the laminate 25 is made from a liquid mixture containing 1 to 4% by weight of a pigment.

[0078] For example, the third layer 24 of the laminate 25 is made from a liquid mixture containing 0.5 to 4% by weight, preferably 0.5 to 1% by weight, of a pigment.

[0079] Figure 2 shows some of the main steps in a method 100 for depositing a visible light absorbing coating 20 on a substrate 1 according to the present invention.

[0080] The deposition method 100 according to the present invention includes a first step 110 of preparing a substrate 1.

[0081] The deposition method 100 according to the present invention includes a second step 120 of depositing an underlayer 21 or a base layer covering at least a part of the substrate 1. This second deposition step 120 is performed by spraying, dipping, screen printing, printing or pad printing a first liquid mixture containing a binder, a solvent, and 5 to 10% by weight of a pigment having a d90 value in the nanometer level, for example less than 100 nm.

[0082] The step 120 of depositing this underlayer 21 includes a sub-step of evaporating the solvent from the liquid mixture applied to the substrate 1 and shrinking the binder around the pigment to form the underlayer 21 of the coating 20.

[0083] The deposition method 100 also includes a third step 130 of depositing a laminate 25 of a plurality of overlapping layers 22, 23, 24 having different particle sizes between the layers of the laminate 25.

[0084] This third step 130 includes a first sub-step 131 of depositing the first layer 22 of the laminate 25 with a liquid mixture containing a binder, a solvent, and 0.5 to 10% by weight of a pigment having a d90 value greater than 100 nm and k / 10 μm. Here, k is a similarity coefficient between the d90 values of the pigments in two consecutive layers of the laminate 25.

[0085] Preferably, the liquid mixture for depositing the first layer 22 contains 4 to 10 wt% of a pigment.

[0086] Preferably, the liquid mixture for depositing the first layer 22 contains 4 to 8 wt% of a pigment.

[0087] This first sub-step 131 is performed by spraying, dipping, screen printing, printing or pad printing.

[0088] This first sub-step 131 includes the step of evaporating the solvent from the liquid mixture applied to the base layer 21, contracting the binder around the pigment, and forming a first layer 22 of the coating 20 overlapping on the base layer 21.

[0089] The third step 130 includes a second sub-step 132 of depositing a second layer 23 of the laminate 25 with a liquid mixture containing a binder, a solvent, and 0.5 to 10 wt% of a pigment having a d90 value of 2k / 10 μm. Here, k is a similarity coefficient between the d90 value of the pigment of the first layer 22 and the d90 value of the pigment of the second layer 23.

[0090] Preferably, the liquid mixture for depositing the second layer 23 contains 1 to 4 wt% of a pigment.

[0091] This second sub-step 132 is performed by spraying, dipping, screen printing, printing or pad printing.

[0092] This second sub-step 132 includes the step of evaporating the solvent from the liquid mixture applied to the first layer 22, contracting the binder around the pigment, and forming a second layer 23 of the coating 20 overlapping on the first layer 22.

[0093] The third step 130 includes a third sub-step 133 of depositing a third layer 24 of the laminate 25 with a liquid mixture comprising a binder, a solvent, and 0.5 to 10 wt% of a pigment having a d90 value of 3k / 10μm. Here, k is a similarity coefficient between the d90 value of the pigment of the second layer 23 and the d90 value of the pigment of the third layer 24.

[0094] Preferably, the liquid mixture for depositing the third layer 24 comprises 0.5 to 4 wt% of the pigment.

[0095] Preferably, the liquid mixture for depositing the third layer 24 comprises 0.5 to 1 wt% of the pigment.

[0096] This third sub-step 133 is performed by spraying, dipping, screen printing, printing, or pad printing.

[0097] This third sub-step 133 includes the step of evaporating the solvent from the liquid mixture applied to the second layer 22, contracting the binder around the pigment, and forming a third layer 24 of the coating 20 overlapping on the second layer 23.

[0098] Of course, the deposition method 100 can include other sub-steps of depositing additional layers according to the desired number of layers in the laminate 25 of the coating 20.

[0099] According to the first example of the present invention, a brass substrate is used, for example, to form a watch face, and the light-absorbing coating according to the present invention is applied thereto.

[0100] The thickness of this brass substrate is, for example, 0.27 mm.

[0101] The underlayer 21 is applied onto the brass substrate by immersing it in an initial liquid mixture containing 2 g of polyurethane resin (Berlacryl), 0.5 g of Emperor 1600 carbon black pigment, and 2.8 g of Berlaflex diluent. This underlayer 21 is dried for 20 minutes to evaporate the diluent.

[0102] The first layer 22 of the laminate 25 is deposited on the base layer 21 by immersing it in a second liquid mixture containing 2 g of polyurethane resin (Berlacryl), 0.3 g of Living Ink pigment, and 3.5 g of Berlaflex diluent. This first layer 22 is dried for 20 minutes to evaporate the diluent.

[0103] The second layer 23 of the laminate 25 is deposited on the first layer 22 by immersing it in a third liquid mixture containing 2 g of polyurethane resin (Berlacryl), 0.2 g of Norit A ultra E153 pigment, and 4 g of Berlaflex diluent. This layer is dried for 20 minutes to evaporate the diluent.

[0104] The third layer 24 of the laminate 25 is deposited on the second layer 23 by immersing it in a fourth liquid mixture containing 2 g of polyurethane resin (Berlacryl), 0.2 g of Norit SX super E153 carbon pigment, 1.5 g of glass melt spheres of 90 - 150 μm, and 4 g of Berlaflex diluent. This layer is dried for 20 minutes to evaporate the diluent.

[0105] Such coating results in a brass watch face with a black surface coating and a luminance component L* of 15.9.

Explanation of Reference Numerals

[0106] 1 Substrate 10 Article 20 Coating 21 Base layer 22 First layer 23 Second layer 24 Third layer 25 Laminate 200 Timepiece

Claims

1. A method (100) for depositing a coating (20) that absorbs visible light onto a substrate (1) to form an article (10), such as a component of a watch, comprising the steps of: A first step (110) of providing a substrate (1); a second step (120) of depositing a base layer (21) formed by depositing a first liquid mixture comprising a binder, a solvent and a pigment having a d90 value of nanometer-level dimensions covering at least a portion of said substrate (1) and evaporating said solvent; a third step (130) of depositing a stack (25) of layers (22, 23, 24) by sequentially depositing a mixture of liquids containing a binder, a solvent and pigments of different particle sizes; The grain size is different between each layer n of the laminate (25), Each layer of the laminate (25) is formed by evaporating the solvent, Each layer n at least partially covers the preceding layer n-1 1. A method (100) comprising:

2. The first liquid mixture forming the undercoat layer (21) of the coating (20) contains 5 to 10% by weight of a pigment.

2. The method (100) of claim 1 .

3. said third step (130) of depositing a stack (25) of layers (22, 23, 24) is carried out by sequentially depositing mixtures of liquids; Each liquid mixture for forming the layers (22, 23, 24) of the laminate (25) comprises a binder, a solvent and a pigment with an increasing d90 value for each successive deposition of the layers forming the laminate (25).

2. The method (100) of claim 1 .

4. Each layer n of the plurality of layers (22, 23, 24) of the laminate (25) contains a pigment having a d90 value corresponding to n k / 10 μm; where k is the similarity coefficient between the d90 values ​​of the pigments in two successive layers of the laminate (25).

2. The method (100) of claim 1 .

5. said third step (130) of depositing a stack (25) of layers (22, 23, 24) is carried out by sequentially depositing a plurality of liquid mixtures; each liquid mixture for forming the layers (22, 23, 24) of the laminate (25) comprises a binder, a solvent and a pigment having an increasing d90 value between successive depositions of the layers of the laminate (25); The weight percent pigment content in each liquid mixture decreases as the pigment's d90 value increases.

2. The method (100) of claim 1 .

6. The mixture of the liquids for forming the layers (22, 23, 24) of the laminate (25) contains 0.5 to 10% by weight of a pigment.

6. The method (100) of claim 5.

7. said third step (130) of depositing the laminate (25) comprises a first substep (131) of depositing a first layer (22) of said laminate (25) by means of a liquid mixture comprising 0.5-10% by weight of a pigment, the d90 value of which corresponds to k / 10 μm; where k is the similarity coefficient between the d90 values ​​of the pigments in two successive layers of the laminate (25).

2. The method (100) of claim 1 .

8. The liquid mixture for depositing the first layer (22) of the laminate (25) comprises 4-10% by weight of a pigment.

8. The method (100) of claim 7.

9. said third step (130) of depositing the laminate (25) comprises a second substep (132) of depositing a second layer (23) of said laminate (25) by means of a liquid mixture comprising 0.5-10% by weight of a pigment having a d90 value corresponding to 2k / 10 μm, where k is the similarity coefficient between the d90 values ​​of the pigments in two successive layers of the laminate (25).

2. The method (100) of claim 1 .

10. The liquid mixture for depositing the second layer (23) of the laminate (25) comprises 1-4% by weight of a pigment.

10. The method (100) of claim 9.

11. said third step (130) of depositing the laminate (25) comprises a third substep (133) of depositing a third layer (24) of said laminate (25) by means of a liquid mixture comprising 0.5-10% by weight of a pigment having a d90 value corresponding to 3k / 10 μm, where k is the similarity coefficient between the d90 values ​​of the pigments in two successive layers of the laminate (25).

2. The method (100) of claim 1 .

12. The liquid mixture for depositing the third layer (24) of the laminate (25) comprises 0.5 to 4% by weight of a pigment.

12. The method (100) of claim 11.

13. The undercoat layer (21) and / or the layers (22, 23, 24) of the laminate (25) are deposited by spraying, dipping, screen printing, printing or pad printing.

2. The method (100) of claim 1 .

14. The first liquid mixture forming the underlayer (21) of the coating (20) and / or the liquid mixture forming the layers (22, 23, 24) of the laminate (25) comprises a binder, a solvent, a pigment, and optionally further comprises a matting agent, glass beads, and / or a dispersing agent.

2. The method (100) of claim 1 .

15. The binder is made of a polymer.

15. The method (100) of claim 14.

16. The binder is made of acrylic, epoxy polymer or polyurethane.

16. The method (100) of claim 15.

17. The first liquid mixture forming the underlayer (21) of the coating (20) and / or the liquid mixture forming the layers (22, 23, 24) of the stack (25) are colored inks.

2. The method (100) of claim 1 .

18. A substrate (1), a coating (20) deposited by the method of claim 1, which absorbs light and has a luminance component L* of less than 20.

1. An article (10) comprising:

19. A component of a portable watch 20. The article (10) of claim 18.

20. Comprising a watch component (10) according to claim 19 A timer (200).

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