Method for manufacturing a component having a microstructure pattern on a colored resin, and component obtained by said method

Abstract

The present disclosure relates to a method for manufacturing a component having a microstructure pattern on a colored resin, comprising: providing a printing mold (30) having a mold pattern (32) comprising structuring elements having a micron-scale and / or nanometer-scale dimension; providing a substrate (10) and forming a colored resin layer (20) on a substrate (10), the resin having at least one coloring agent; replicating on the resin layer (20) a replicated pattern (22) corresponding to the negative of the mold pattern (32), comprising pressing the printing mold (30) against the resin layer (20); and crosslinking the resin (20) so as to produce a cured resin having the replicated pattern (22). The mold pattern (32) comprises structuring elements having a mean lateral dimension between 1 nm and 5000 μm, and an aspect ratio between the height of the structuring elements and the mean lateral dimension between about 0.1 and 2.

Description

A method for manufacturing a component having a microstructure pattern on a colored resin and a component obtained by said method technical field

[0001] This disclosure relates to the manufacture of a component featuring a microstructure pattern on a colored resin. Specifically, the component may include a watch component, a jewelry component, a micromechanical component, a security and / or anti-counterfeiting element, or a decorative component. In particular, this disclosure relates to the manufacture of a watch dial incorporating such a microstructure pattern. State of the art

[0002] Colored lacquers or thin film stacks produced by PVD / ALD are commonly used to control the color of watch dials. While thin film stacks can be as thin as a few hundred nanometers to a few micrometers, a considerable thickness, up to 100 micrometers, is required for lacquers. In practice, only thin film stacks can be used to conformally coat a guilloché or machined pattern or surface textures (sun-blasted, sandblasted, shot-blasted, etc.) that have ridges with lateral dimensions of a few micrometers to a few millimeters and depths of a few tens of micrometers, thus imparting color while preserving the decorative optical effect provided by the machined pattern. Applying a lacquer to such patterns results in a loss of pattern sharpness and a degradation of the optical effect produced by the guilloché or machined design.

[0003] Furthermore, although the color palette for thin film stacks is constantly improving, each color requires a CSEM-165-PCT A specific design is required to achieve the correct Pantone color and avoid color shifts when the viewing angle changes. Furthermore, the final effect is difficult to predict on textured surfaces. Certain colors, such as warm red, are also difficult to achieve using thin-film deposition techniques.

[0004] Document CH709669A1 describes the use of a combination of a partially reflective PVD coating with a thin ALD coating to obtain a range of interference colors from browns, magenta, blue, yellow, orange, violet, green, and pink, depending on the thickness of the ALD coating. The underlying PVD coating allows for modulation of the color brightness.

[0005] To overcome angular dependence, it is possible to introduce surface roughness under the stack of thin films (see for example, Blàsi, T. Kroyer, TE Kuhn and O. Hôhn, "The MorphoColor Concept for Colored Photovoltaic Modules," in IEEE Journal of Photovoltaics, vol. 11, no. 5, pp. 1305-1311, 2021).

[0006] From an industrial point of view, the thickness of the layers depends on the specific surface area of ​​the parts to be treated, which can lead to problems of reproducibility or flexibility when processing structured / textured parts.

[0007] Other examples of vacuum-deposited layer stacking exist that produce optical effects without angular dependence. For example, it is possible to deposit colored layers by PVD using metal oxides or, more generally, semi-absorbent and transparent dielectric layers. This approach is used in document EP2392689A1 to achieve a specific red coloration. To do this, an iron oxide film is deposited by PVD and combined with a transparent layer. CSEM-165-PCT

[0008] Other coloring methods are possible, such as the production of colloidal glasses. The effect obtained is very attractive because it is free from angular dependence, but the color palette remains limited (see, for example, S. Magkiriadou, J. Park, YS Kim, and VN). Manoharan On the Absence of Red Structural Color in Photonic Glasses, Bird Feathers and Certain Beetles, Phys. Rev. E 90, 062302. Disclosure Summary

[0009] This disclosure relates to a method for manufacturing a component featuring a microstructure pattern on a colored resin, comprising: provide a printing mold comprising a mold pattern including structural elements having a micrometric size dimension; provide a substrate and form a layer of colored resin on a substrate, the resin comprising at least one coloring agent; to replicate on the resin layer a pattern corresponding to the negative of the mold pattern, including applying the printing mold against the resin layer; and crosslink the resin to produce a hardened resin with the replicated pattern.

[0010] The mold pattern includes structural elements having an average lateral dimension between 10 jim and 5000 |im, and an aspect ratio between the height of the structural elements and the average lateral dimension between 0 and 10, for example between 0.1 and 10, between 0.5 and 5, or between 0.5 and 2.

[0011] The range of structure sizes from 10 jim to 5000 jim allows for typical watchmaking reflection effects such as guilloché, sunburst, etc., while eliminating the effects CSEM-165-PCT unwanted interference that could appear with sub-micrometer-sized structures.

[0012] Advantageously, the resin can have a refractive index ranging from 1.5 to 2.0, which increases the surface reflectivity. Maximizing the difference in refractive index with air further increases reflectivity.

[0013] Advantageously, the resin colorants can be significantly smaller than the replicated structures to be as close as possible to the surface. The ratio between the lateral size of the microstructure and the diameter of the colorants can advantageously be at least 3, or even at least 10.

[0014] If the coloring agent is a pigment, its refractive index can advantageously range from 1.5 to 3.0, allowing for modulation of light diffusion by the pigments incorporated into the resin. Light diffusion is also influenced by the size of the pigments. This allows for modification of the resin's opacity.

[0015] The combination of a replicated microstructure and a colored resin with a well-defined refractive index allows for a surface that creates plays of light depending on the slopes of the patterns and the angle of view, while maintaining a well-defined color and controlled opacity.

[0016] The component may include a watch component, a jewelry component, a micromechanical component, a security and / or anti-counterfeiting element, or a decorative component.

[0017] This disclosure further relates to a watch dial obtained by the process and comprising such a microstructure pattern. CSEM-165-PCT Brief description of the figures

[0018] Examples of implementation of the invention are given in the description illustrated by the accompanying figures, in which: Figure 1 shows a layer of resin formed on a substrate and a printing mold having a mold pattern; according to one embodiment; Figure 2 shows a replication step comprising the application of a structured surface with the mold pattern of the printing mold against a printing surface of the resin layer, according to one embodiment; Figure 3 shows a stamping column to perform the replication step; Figure 4 shows the illumination of the resin during a resin crosslinking step, according to one embodiment; Figure 5 shows the crosslinked resin layer with a replicated pattern, separated from the printing mold; and Figures 6a-c show examples of the printing mold with its mold pattern (top) as well as the replicated pattern (bottom), corresponding to a pattern including angles (figure 6a), of hemispherical type (figure 6b), and of crenellated type (figure 6c). Figures 7a and 7b show examples of the printing mold with its mold pattern (top) and the replicated pattern (bottom), corresponding to straight (Figure 7a) and curved (Figure 7b) inclined structures producing a color gradient effect; and Figure 8 shows the replicated pattern being covered by an additional layer. CSEM-165-PCT Detailed description

[0019] According to an embodiment illustrated in Figures 1 to 5, a process for manufacturing a component having a microstructure pattern on a colored resin. The process comprises the steps of: provide a printing mold 30 comprising a mold pattern 32 including structural elements having a micrometric size dimension; provide a substrate 10 and form a layer of colored resin 20 on the substrate 10, the resin 20 comprising at least one coloring agent; to replicate on the resin layer 20 a replicated pattern 22 corresponding to the negative of the mold pattern 32, including the application of the printing mold 30 against the resin layer 20; and crosslink (harden) the resin 20 so as to produce a hardened resin having the replicated pattern 22.

[0020] Figure 1 shows the resin layer 20 formed on an upper surface 11 of the substrate 10, and the printing mold 30 having the mold pattern 32 on the side of a structured surface 31 of the printing mold 30. In order to ensure good adhesion between the resin 20 and the substrate 10, a primer layer (or priming layer) can be formed on the substrate 10 prior to the formation of the resin layer 20. The application of the resin layer 20 on the upper surface 11 of the substrate 10 can be carried out using a dispensing method, for example by "spin coating" in which layers of resin 20 are spread on the center of the substrate 10 and then spread by rotating the substrate 10 around a central axis. Replication

[0021] Figure 2 shows the replication step comprising the application of the structured surface 31 with the mold pattern 32 of the printing mold 30 against a printing surface 21 of the resin layer CSEM-165-PCT 20. According to one embodiment, a pressure of the order of 10 to 30 kPa is applied between the printing mold 30 and the resin layer 20. Generally, the application of the printing mold 30 against the resin layer 20 is carried out in such a way that the protrusions of the mold pattern 32 penetrate well into the resin 20 and that the cavities of the mold pattern 32 are completely filled with resin 20 (without formation of air pockets).

[0022] The replication step can be carried out using a stamping column 50, as illustrated in Figure 3. The stamping column 50 may include a mold holder 51 to which the printing mold 30 is fixed and a resin holder 52 to which the substrate 10 and the resin 20 are fixed. The mold holder 51 moves substantially vertically relative to the resin holder 52 by means of a rising and falling column 53, which can be driven by a drive motor 54. The movement of the mold holder 51 can be guided by one or more guide columns 55 so that the mold holder 51 remains aligned with the resin holder 52. The latter is fixed relative to the rising and falling column 53. The rising and falling column 53 brings the printing mold 30 into contact with the resin 20 and applies pressure as defined above.

[0023] Compared to a replication process using a thermal resin, the replication process with a UV-curable resin allows for greater fidelity of the replicated pattern 22 on the resin 20 compared to the mold pattern 32. This is because the replication is carried out at room temperature or low temperature, for example, between 20 and 80°C. The curable resin is typically liquid (low viscosity) and can therefore better conform to the mold patterns before photocuring. Furthermore, photocurable resins generally exhibit a lower shrinkage rate (due to the chemical crosscuring reaction) than thermosetting resins, which facilitates demolding. In the case of replication with a thermal resin, the high temperatures also cause thermal expansion of the resin, making the demolding step problematic (see below). CSEM-165-PCT Resin

[0024] In one embodiment, resin 20 comprises a UV-curable (or UV-curable) resin. For example, resin 20 may comprise at least one of the following: acrylate monomers, acrylate oligomers, epoxies, silicone, or silicone acrylate. Resin 20 may also comprise a sol / gel or a monomer of acrylate and silica, as well as inorganic fillers (silica, alumina, or titanium nanoparticles) to modify its mechanical and optical properties.

[0025] In another embodiment, Resin 20 is a thermosetting resin. The resin curing step can then be carried out by heating the resin to a curing temperature (RT). The curing temperature depends on the chemical nature of the resin and the presence of a thermoinitiator (typically TAGs (Thermal Acid Generators)). Typically, a curing temperature of 20 to 200°C is used, more precisely 20 to 160°C.

[0026] The colored resin layer 20 can have a thickness between 10 µm and 500 µm. The thickness of the colored resin layer 20 must be adjusted to achieve the desired color effect and reproduce the mold pattern. For example, the colored resin layer 20 must be thick enough to ensure sufficient colorant is present within the layer to achieve the desired color density.

[0027] The thickness of the resin layer can be adjusted to obtain a minimum thickness d of the resin layer 20 containing the replicated pattern. For example, the minimum thickness d can correspond to the thickness of the resin layer 20 at the deepest recess of the replicated pattern (see Figure 5). The minimum thickness d ensures that a sufficient quantity of colorant is present within the resin layer 20 to achieve the desired coloration. CSEM-165-PCT

[0028] The minimum thickness d can be controlled during the replication step by controlling the distance between the printing mold 30 and the upper surface 11 of the substrate 10. According to one embodiment, the stamping column 50 can be provided with at least one stop 56 (see figure 5) configured to bear against the mold support 51, during the replication step, so that the most salient structure of the mold pattern 32 is at a distance from the upper surface 11 of the substrate 10 which corresponds to the minimum thickness d.

[0029] In one particular execution, the refractive index of resin 20 is at least 1.5, advantageously between 1.5 and 2.0. A refractive index of 1.5 or higher increases the surface reflectivity. Sufficient reflectivity is indeed important to achieve the advantages of the replicated pattern, such as the plays of light typical of watchmaking decorations like guilloché or sunburst finishes. According to Fresnel's law, the surface reflectivity increases with the difference in refractive index between the resin and the air.

[0030] Among existing photocurable resins, acrylate or epoxy acrylate base resins can be advantageously used. The presence of inorganic fillers (e.g., silicon dioxide, zirconium oxide, titanium dioxide) allows for adjustment of the refractive index. Examples include Ormocers commercial resins: Ormocore Ormoclad, Ormoclear; Panacol Vitralit UC 1633; Evonik Nanocryl C130 C150; DELO Katiobond OM614; Photobond OM4310; Addison Clearwave L2002-C56; and LuxNIL P270-U. Crosslinking

[0031] Figure 4 shows the irradiation of the photocurable resin 20 with UV illumination 40. According to the embodiment illustrated in Figure 4, the curing step of the resin 20 is carried out before the separation step, with the printing mold 30 remaining in contact with the resin 20. In the example shown, the printing mold 30 is interposed between CSEM-165-PCT For the UV illumination 40 and the resin 20, the printing mold 30 must be sufficiently transparent to the emission spectrum of the UV illumination 40 to allow the resin layer 20 to crosslink throughout its entire thickness. For example, the printing mold 30 could be made of glass or a polymer transparent to the emission spectrum of the UV illumination 40.

[0032] In another embodiment not shown, the irradiation of the resin 20 can be carried out through the substrate 10. In this case, the substrate 10 must be sufficiently transparent to the emission spectrum of the UV illumination 40 to be able to crosslink the resin layer 20 throughout its thickness.

[0033] According to one embodiment, the stamping column 50 includes an irradiation system 57 providing UV illumination 40. With reference to Figure 3, the stamping column 50 can be configured to allow UV illumination 40 to pass through the mold support 51 and printing mold 30, up to the resin layer 20.

[0034] In the case where the resin 20 includes a thermosetting resin, the step of crosslinking the resin can then be carried out by heating the resin 20 via a heating element 58 arranged near the resin 20. The heating element 58 is configured to be able to heat the resin to the crosslinking temperature TR.

[0035] The manufacturing process may also include a post-curing step to ensure complete cross-linking of the resin. This post-curing step may involve additional irradiation or heating, depending on whether the resin is photocurable, thermosetting, or both.

[0036] During the curing step, the intensity of the UV radiation 40 can be adjusted to take into account the presence of the coloring agent in the resin 20. For example, the intensity of the UV radiation 40 for the resin containing the coloring agent will be higher than in the case of a CSEM-165-PCT Resin without coloring agents. The intensity of the UV 40 radiation is also adjusted according to the thickness of the resin layer. The intensity of the UV 40 radiation can be adjusted via the exposure time and irradiance. For example, the irradiance can be between 10 and 500 mW / cm². 2 .

[0037] After the resin 20 crosslinking step, the process may also include a step of separating the crosslinked resin, which contains the replicated pattern 22, from the printing mold 30 (demolding step). The crosslinked resin layer 20 containing the replicated pattern 22, separated from the printing mold 30, is shown in Figure 5. The replicated pattern 22 corresponds to the negative of the mold pattern 32. The textured surface 31 of the printing mold 30 can be treated to facilitate demolding. For example, the textured surface 31 can be coated with a non-stick layer. Coloring agent

[0038] In one embodiment, the coloring agent comprises an inorganic pigment. Such a pigment ensures homogeneous dispersion of the pigment (particle) within the photocurable resin matrix. The resulting colored resin is stable because the pigments retain their initial size distribution and do not exhibit aggregation during the formulation, deposition, texturizing, and photocuring steps. This parameter is crucial for controlling the stability of the final color of the structured and crosslinked resin.

[0039] Complete curing of the pigmented resin requires good UV propagation from the mold interface to the substrate. This can be achieved by properly controlling the UV transparency of the pigments, the refractive index of the pigment relative to the resin, and / or the pigment concentration in the resin.

[0040] The pigment may be at least partially transparent to UV light. Low absorption allows UV light to propagate throughout CSEM-165-PCT The thickness of the pigmented resin. The size of the pigment relative to the size of the replicated pattern 22 must also be considered. For example, a pigment larger than the size of the micrometric structures of the printing mold 30 will not allow the colored resin 20 to fill the structures of the printing mold 30, but only the transparent resin (without pigment). A pigment at least three to ten times smaller than the size of the micrometric structures of the printing mold 30 will allow the colored resin 20 (containing the pigments) to fill the structures of the printing mold 30. Here, the size of the micrometric structures can be considered as the average lateral dimension of the mold pattern 32 (see below).

[0041] Unlike using a dye to color the resin, pigment allows for dispersion rather than a solution when mixed with the resin. During the resin crosslinking step, UV radiation is scattered by the pigment particles. If the pigment has a refractive index similar to that of the resin, scattering is weak, and UV radiation propagates through the resin layer, provided the pigment does not absorb in the UV range. If there is a difference in refractive index between the resin and the pigments, UV propagation will depend on the pigment concentration and the scattering properties of the particles (diameter, difference in refractive index). In the case of a low pigment concentration, the system is described by a ballistic regime, while a multiple scattering regime is observed for a high concentration (G. Jacucci, L. Schertel, Y. Zhang, H. Yang, S.Vignolini, Light Management with Natural Materials: From Whiteness to Transparency. Adv. Mater. 2021, 33, 2001215). There is therefore a compromise regarding the type of pigment and its concentration allowing crosslinking to the interstitial resin (between the pigment particles) to be crosslinked more deeply into the thickness of the resin layer 20.

[0042] Here, the term "pigment" can mean a single pigment (one type of pigment) or multiple pigments (multiple types of pigments). The pigment can be an inorganic pigment, for example, comprising a CSEM-165-PCT Cobalt blue, such as cobalt aluminate blue spinel blue, CAS 1345-16-0. More generally, the pigment may be chosen from a group of pigments comprising at least one compound such as: hematite and corundum, rutile, titanate, spinel, pseudobrookite, tin and zinc titanate, chromium oxide, iron oxide, perovskite, lead chromate, lead molybdate, vanadate, ultramarine blue, cerium(III) sulfide, or pyrochlore. The compound must be insoluble in the UV-curable resin.

[0043] In another embodiment, the pigment can be organic or metalorganic. In this case, the molecule constituting the pigment is not soluble in the resin and forms particles and a dispersion similar to that of inorganic pigments. Examples of organic pigments include azopigments, copper phthalocyanine, alizarin, quinacridone, indanthrone, chinacridone, dioxazine, and diketopyrrolo-pyrrole.

[0044] The concentration of pigment in resin 20 must allow for low UV absorption of the pigment so that resin 20 can properly harden during the crosslinking step.

[0045] According to one embodiment, the pigment has a refractive index (for wavelengths in the visible range) between 1.5 and 3.0. The refractive index of the pigment can be adjusted relative to the refractive index of the resin 20 in order to modulate the light scattering, which alters the opacity of the colored resin and the clarity of the color.

[0046] According to an advantageous embodiment, the UV refractive index of the pigment is similar to the refractive index of the resin. For example, the UV refractive index of the pigment is substantially the same as the refractive index of the resin. For example, the UV refractive index can be between 1.5 and 1.6 for conventional UV resins. Light scattering requires different refractive indices between the pigment and the resin. With a correspondence of CSEM-165-PCT The refractive index reduces diffusion phenomena. This limits the effects of light scattering and promotes the propagation of UV radiation throughout the entire thickness of the resin layer 20. Note that UV radiation can also propagate through the thickness of the resin layer 20 by multiple diffusion.

[0047] Too high a pigment concentration can limit the depth of UV penetration during curing, while too low a concentration will result in a poorly saturated color. More generally, the pigment concentration in the resin 20 allows control over the color throughout the volume of the resin 20, while ensuring that the colored resin remains sufficiently transparent to UV radiation throughout the entire thickness of the resin layer 20, thus allowing the resin layer 20 to harden during the curing step.

[0048] In one embodiment, the resin 20 comprises from approximately 1% by weight to approximately 10% by weight, relative to the total weight of the resin dispersion, of at least one pigment dispersed in the resin. The resin 20 may also comprise between 1% and 15% by weight, or even 1% to 25% by weight.

[0049] At least one additive may be added to the resin 20 along with the pigment. For example, the additive may include dispersants and adjuvants, added to the resin 20 with the pigment to prevent the pigment particles from clumping and to improve their dispersion within the resin 20. Such additives may include the product Solsperse™ manufactured by Lubrizol Advanced Materials, Inc. (such as Solsperse 36000, 71000, 74000, 75000, 78000, 85000, 86000, 87000). Additives intended to improve the adhesion of the resin layer 20 to the substrate 10 and / or the quality of demolding may also be added to the resin. Ligands, or any other functional surface chemistry, can also be used to control the good quality of the dispersion and ensure the stability of the pigments. CSEM-165-PCT

[0050] In another embodiment, the coloring agent comprises at least one dye. For example, the coloring agent may include an organic or metallorganic dye. Since the dye molecule is dissolved in the resin, sufficient UV transparency is necessary to ensure good crosslinking. The advantages of dyes are intense colors, good homogeneity (allowing colored resin to be present in the microstructures to be replicated), and a lower environmental impact than inorganic pigments. However, their UV stability is lower compared to inorganic pigments. Examples of dyes include anthaquinone, acridine, arylmethane, diarylmethane, triarylmethane, azodys, diazonium dyes, quinone-imine, tetrazolium, thiazole, and xanthene.

[0051] The integration of the coloring agent into the resin 20 makes it possible to obtain a "deeper" color than in the case of a transparent resin formed on a colored substrate. Mold pattern

[0052] The mold pattern 32 (and therefore the replicated pattern 22) may include structural elements, such as decorative elements that create plays of light by spatially modulating the surface reflectivity (guilloché, sunburst). In particular, the replicated pattern 22 can allow for spatial modulation of the surface reflectivity (illuminated and unlit areas). In this case, the mold pattern 32 (and therefore the replicated pattern 22) has an average lateral dimension of, for example, between approximately 10 jim and 5000 jim, and an aspect ratio between the height of the structural elements and the average lateral dimension of, for example, between 0 and 10, between 0.1 and 10, between 0.5 and 5, or between 0.5 and 2.

[0053] The combination of the replicated pattern 22 and the colored resin with a well-defined refractive index allows for a surface that gives rise to CSEM-165-PCT to plays of light depending on the geometry of the replicated pattern 22, while having a well-defined color and controlled opacity.

[0054] For example, the geometry of the replicated pattern 22 may include inclined or curved sides, for example, imitating classic guilloché or sunburst patterns. Such a pattern allows for the spatial modulation of surface reflections.

[0055] The microstructure of the mold pattern 32 (and the replicated pattern 22) can be arranged so as to be used in a way that induces diffuse reflectance.

[0056] In one embodiment, mold pattern 32 includes a decorative motif intended to decorate a component of a watch. For example, mold pattern 32 may include a decorative motif, such as a guilloché pattern, intended to decorate a watch dial. Printing mold

[0057] The printing mold 30 can be obtained by supplying or producing a master tool made of a hard, machinable material, for example, a metal or alloy, brass, steel, or silicon, and comprising a pattern corresponding to the negative of the mold pattern 32 to be produced. It is also possible to replicate the mold pattern structure in a transparent resin. In this case, the transparent resin is the printing mold 30 and will comprise a pattern corresponding to the negative of the mold pattern 32 to be produced. As mentioned below, the structured surface 31 of the printing mold 30 can be coated with a non-stick layer. CSEM-165-PCT

[0058] Mold pattern 32 can be produced by mechanical and / or chemical machining, chiseling, beading, microblasting, sandblasting, satin finishing, polishing, laser engraving, and / or tribofinishing (trowalizing).

[0059] The mold pattern 32 may also include Geneva ribs, angling, sunburst, and / or snailing.

[0060] Figures 6a to 6c show examples of the printing mold 30 with its mold pattern 32 (top) and the replicated pattern 22 (bottom), corresponding to a pattern including angles, such as for a guilloché pattern (Figure 6a), a hemispherical type, such as for a beaded pattern (Figure 6b), and a crenellated type (Figure 6c). The crenellated pattern's flanks may include vertical or inclined sides.

[0061] The process described here makes it possible to manufacture several unique combinations of replicated patterns 22 (for example guilloché patterns or any other pattern containing micrometric-sized structures) on a resin whose color can be chosen independently of the replicated pattern 22.

[0062] Indeed, the addition of a coloring agent allows the selection of a color of the resin 20 before replication, for example choosing one of the pantone colors based on the choice of pigment and its concentration in the resin 20.

[0063] It is understood that the present invention is not limited to the embodiment just described and that various simple modifications and variants can be envisaged by a person skilled in the art without departing from the scope of the present invention.

[0064] For example, the mold pattern 32 can be manufactured using different structuring techniques such as guilloché but CSEM-165-PCT also chiseling, beading, microblasting and sandblasting, satin finishing, polishing, laser engraving, and / or tribofinishing.

[0065] According to another embodiment, the mold pattern 32 may include inclined structures configured so that the replicated pattern 22 produces a color gradient effect caused by a thickness gradient in the resin layer 20 resulting from the replicated pattern 22. For example, the inclined structures may have an average lateral dimension of more than 1 mm. For example, the inclined structures of the mold pattern 32 may have a maximum height (or a maximum depth of the inclined structures in the replicated pattern 22) equal to or similar to the minimum thickness d, for example, equal to or greater than the minimum thickness d. Figures 7a and 7b show examples of the printing mold 30 with its mold pattern 32 (top) and the resulting replicated pattern 22 (bottom), corresponding to straight (Figure 7a) and curved (Figure 7b) inclined structures producing the color gradient effect.

[0066] In another example, said at least one additive may include diffusing particles enabling a colouring with a transparency gradient to be obtained, the diffusing power being adjusted with the concentration of diffusing particles, and the type of particles.

[0067] In another example illustrated in Figure 8, the process also includes a step of covering the resin layer 20 with the replicated pattern 22 with an additional layer 60. The additional layer 60 is preferably transparent so as not to alter the perceived color of the resin layer 20. The additional layer 60 can be added to protect the resin layer 20 and / or to adjust the surface reflectivity of the component. The additional layer 60 can be formed by vacuum deposition methods (PVD, ALD) or by wet deposition methods (spray, jetting, dipping).

[0068] In yet another example, the pigment may contain metallic nanoparticles. Metallic nanoparticles may be CSEM-165-PCT They are primarily composed of metals such as silver, gold, aluminum, and / or copper. The nanoparticles should be capable of generating a surface plasmon resonance effect.

[0069] In yet another example, mold pattern 32 may include a pattern intended for security and / or anti-counterfeiting applications, such as a colored optical diffractive element.

[0070] The component manufactured by this process may include a watch component, a jewelry component, a micromechanical component, a security and / or anti-counterfeiting element, or a decorative component. The watch component may, for example, be a dial or a hand.

[0071] In one embodiment, the component is a dial. In this case, the substrate 10 can be made of brass or any other suitable material.

[0072] If the component is a dial, the process may include an additional machining step of the substrate 10 containing the colored resin 20 with the replicated pattern 22 (preferably after the curing step). This machining step may include machining openings, for example, to form one or more through holes and one or more apertures. The machining step may also include a deburring step to remove excess resin from the periphery of the dial, which may result from material leakage between the substrate and the mold during the deposition, molding, or curing steps of the colored resin. The deburring step thus preserves the original lateral dimensions of the dial after the deposition and texturing of the colored resin. The machining step may also include a diameter-cutting step.

[0073] It should be noted that the colored resin deposition process 20 described above is compatible with the usual watch dial manufacturing techniques, which often involve dial treatments in CSEM-165-PCT Liquid-based methods, for example during cleaning or zaping processes (application of a transparent lacquer). Therefore, this solution is more easily integrated by dial manufacturers than dial coloring treatments performed using vacuum deposition techniques.

[0074] This disclosure relates to a component obtained by the process. CSEM-165-PCT Reference numeral used in the figures 10 substrate 11 upper surface of the substrate 20 resin 21 resin printing surface 22 replicated pattern 30 printing molds 31 structured surface 32 mold pattern 40 UV illumination 50 stamping column 51 mold support 52 resin support 53 Rising and descending column 54 Drive motor 55 guide column 56 stop 57 irradiation system 58 heating element 60 additional layers minimum thickness CSEM-165-PCT

Claims

Demands 1. A method for manufacturing a component having a microstructure pattern on a colored resin, comprising: provide a printing mold (30) comprising a mold pattern (32) including structural elements having a micrometric size dimension; provide a substrate (10) and form a layer of coloured resin (20) on the substrate (10), the resin (20) comprising at least one colouring agent; to replicate on the resin layer (20) a replicated pattern (22) corresponding to the negative of the mold pattern (32), including the application of the printing mold (30) against the resin layer (20); and crosslink the resin (20) so as to produce a hardened resin having the replicated pattern (22); characterized in that the mold pattern (32) comprises structural elements having an average lateral dimension between 10 |im and 5000 |im, and an aspect ratio between the height of the structural elements and the average lateral dimension between about 0.1 and 10; and in that the refractive index of the resin (20) is between 1.5 and 2.

0.

2. The method according to claim 1, in which the mold pattern (32) may include structural elements having an average lateral dimension between 10 jim and 500 |im, the aspect ratio between the height of the structural elements and the average lateral dimension being between 0.1 and 10.

3. The method according to claim 1 or 2, in which the resin (20) is a photocurable resin; and in which crosslinking the resin is achieved by irradiation with UV illumination (40). CSEM-165-PCT 4. The method according to claim 1 or 2, wherein the resin (20) is a thermosetting resin; and in which crosslinking the resin is achieved by heating the resin to a crosslinking temperature (TR) of 20 to 200°C.

5. The method according to any one of claims 1 to 4, further comprising a step of separating the resin (20), crosslinked and comprising the replicated pattern (22), from the printing mold (30).

6. The method according to any one of claims 1 to 5, in which the colored resin layer (20) has a thickness between 10 µm and 500 µm.

7. The method according to any one of claims 1 to 6, in which, during the replication step, the distance between the printing mold (30) and the upper surface (11) of the substrate (10) is controlled so as to have a minimum thickness (d), corresponding to the thickness of the resin layer (20) at the level of the deepest hollow of the replicated pattern (22), so as to obtain the desired coloring.

8. The method according to any one of claims 1 to 7, in which the coloring agent comprises at least one pigment, in particular an inorganic pigment.

9. The method according to claim 8, in which the refractive index of the pigment is between 1.5 and 1.6 or between 1.5 and 3.

0.

10. The method according to claim 8 or 9, in which the resin 20 comprises from about 1% by weight to about 10% by weight, relative to the total weight of the resin dispersion (20), of at least one pigment in dispersion in the resin. CSEM-165-PCT 11. The method according to any one of claims 1 to 10, in which the mold pattern (32) includes inclined structures configured so that the replicated pattern (22) produces a color gradient effect caused by a thickness gradient of the resin layer (20) resulting from the replicated pattern (22).

12. The method according to any one of claims 1 to 11, further comprising a step of covering the resin layer (20) with the replicated pattern (22) with an additional layer (60) in order to adjust the reflectivity of the surface of the component.

13. The method according to any one of claims 1 to 12, in which the mold pattern (32) includes a guilloché pattern, Geneva stripes, anglage, soleillage, or colimaçonnage.

14. The method according to any one of claims 1 to 13, in which the component includes a watch component, a jewelry component, a micromechanical component, a security and / or anti-counterfeiting element, or a decorative component.

15. The method according to claim 14, in which the component includes a watch dial. CSEM-165-PCT

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