Manufacturing method for enameled watch parts

Abstract

To provide a method for manufacturing a timepiece component including colored enamel plating.SOLUTION: A method includes: a step of providing a base material 20 selected from materials withstanding an enamel baking temperature; a step 22 of formulating a colored enamel composition constituting colored enamel plating of a timepiece component, including a step 24 of sealing a color pigment in a transparent protective shell made of an inorganic material, and a step 25 of mixing the sealed coloring pigment with an enamel formulation; a step 27 of applying at least one layer of the formulated colored enamel composition onto a reception region on the base material; and a step 28 of baking the layer of the colored enamel composition included in the reception region.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a watch part including an enamel plating mixed with a coloring pigment.

[0002] The present invention also relates to a watch part characterized by such enamel plating and a watch such as a wristwatch including such a watch part.

Background Art

[0003] In the field of watch manufacturing technology, watch parts including enamel plating such as enamel dials have been known for a very long time. Such enamel dials are substantially unalterable and have the interesting feature that they can be used to create decorations with a very bright and rich color palette including coloring pigments containing cadmium or selenium.

[0004] However, due to their toxicity, such coloring pigments no longer meet the certification standards for watch exterior parts.

[0005] Therefore, it is clear that a solution alternative to the prior art needs to be found.

Summary of the Invention

Problems to be Solved by the Invention

[0006] In particular, the present invention aims to improve various drawbacks of the prior art.

[0007] The present invention further aims to obtain a watch part including an enamel plating containing a non-toxic coloring pigment, particularly a pigment of a bright color.

Means for Solving the Problems

[0008] For this purpose, one aspect of the present invention relates to a method for manufacturing a watch part including a colored enamel plating, the method comprising The steps include: providing a substrate selected from materials that can withstand enamel firing temperatures; - A step of preparing a colored enamel composition constituting the colored enamel plating of the watch parts, comprising the steps of encapsulating a colored pigment in a transparent protective shell made of an inorganic material, and mixing the encapsulated colored pigment with the enamel preparation, The steps include: applying at least one layer of the formulated colored enamel composition to a receptive area on a substrate; - A step of firing the layer of the colored enamel composition contained in the receiving region. Includes.

[0009] In other embodiments, • In the encapsulation step, a process is applied to the entire surface of each colored pigment to form a homogeneous, compatible material layer made of metal oxides. The formation process is carried out using ALD technology and / or microemulsion technology. • The colored enamel composition contains encapsulated coloring pigments in a mass percentage of up to 30%. • The colored enamel composition contains encapsulated coloring pigments in a mass percentage of up to 50%. A processing step for the receiving region on a substrate to which a layer of colored enamel composition is applied, the step comprising applying a degreasing agent and / or adhesive to the receiving region. A finishing / finishing step performed on a substrate in an area that will receive a layer of a colored enamel composition, wherein the step includes a stone cutting substep and a polishing substep. Each pigment is a light-colored pigment. Each coloring pigment is an inorganic pigment or a non-toxic inorganic pigment.

[0010] Another aspect of the present invention relates to watch components that can be obtained using this method.

[0011] Advantageously, this watch component includes a substrate selected from materials configured to withstand enamel firing temperatures, and the receiving area on the substrate includes a colored enamel plating containing encapsulated bright-colored inorganic non-toxic pigments.

[0012] Another advantage is that the watch components include plating that forms decorative elements.

[0013] Another aspect of the present invention also relates to a clock that includes such a clock component. [Brief explanation of the drawing]

[0014] Other features and advantages of the present invention will become clearer from reading the following description relating to specific embodiments of the invention, which are provided merely as illustrative and non-limiting examples, and from the accompanying drawings. [Figure 1] This is a schematic diagram of a watch, including watch components such as a dial with colored enamel plating, according to one embodiment of the present invention. [Figure 2] This flowchart shows a method for manufacturing watch components, such as dials, that include enamel plating mixed with bright-colored pigments, according to one embodiment of the present invention. [Modes for carrying out the invention]

[0015] Referring to Figures 1 and 2, the present invention relates to a method for manufacturing a watch component 2 including a colored enamel plating. Such a method is used to obtain a watch component 2 for a watch 1, which includes a substrate having a receptive area 8 containing this enamel plating mixed with a light-colored pigment. This receptive area 8, which is included on the outer surface of the substrate / watch component 2, may include all faces of the substrate / watch component 2, or only one face, or one or more distinct parts of a single face or a number of different faces. Thus, in these different modifications, this plating 10 can be involved in forming a decorative element on the watch component 2.

[0016] Referring to FIG. 1, for a better understanding of the present invention, the clock part 2 is, in this case, an exterior part such as the dial 2 of the clock 1. This dial 2 includes a colored enamel plating 10 located in its receiving area 8 on its visible surface 9. However, it should be noted that this clock part 2 can be other exterior parts such as a bezel, a moon phase, a date disk 7, a dial index, etc.

[0017] In this embodiment, the clock, which can be a wristwatch, includes an analog display dial 2, an hour hand 3a, a minute hand 3b, and a second hand 3c, which can move facing the time markers 5 printed on the time display circle 4. In the illustrated example, the dial 2 includes an opening 6 that penetrates the entire thickness of the dial 2, and the date disk 7 moves under the opening 6.

[0018] In this regard, such a manufacturing method includes a providing step 20, in which a substrate is provided to form this clock part 2. Such a step 20 can include a punching sub-step 21, in which the substrate is punched into a plate according to the dimensions of the clock part 2 to be manufactured, and the plate can have a thickness suitable for the part 2. This plate, and thus this substrate, is made of a material configured to withstand the enamel firing temperature. These temperatures are preferably above 500 degrees Celsius or between 700 degrees Celsius and 1,300 degrees Celsius. As an example, this material can be a metal or a metal alloy, such as steel, or a ceramic.

[0019] Such a material can be transparent, such as a single-crystal or polycrystalline material like quartz, spinel or corundum, especially sapphire. Amorphous materials such as mineral glass can also be used if their softening point is higher than the enamel firing temperature.

[0020] Next, this method includes the formulation step 22 of the colored enamel composition. This step 22 then includes the production sub-step 23 of the enamel formulation. Specifically, this can be the production sub-step 23 of a colorless, colored, translucent or transparent enamel formulation. This production sub-step 23, although not described in detail herein, is well-known in the prior art and is carried out using operating methods and manufacturing methods that enable the obtaining of a colorless, colored, translucent or transparent enamel formulation. In particular, it should be noted that this formulation is produced using an aqueous or oily base that is mixed with the enamel. Further, the colorless or colored enamel formulation is also referred to as the "original colorless or colored enamel composition".

[0021] Next, this step 22 includes the encapsulation sub-step 24, in which the coloring pigments are encapsulated within a protective transparent shell of an inorganic material, also known as a "protective transparent envelope of inorganic material". Such a sub-step 24 involves encapsulating each pigment used in the colored enamel composition within such a transparent protective shell, particularly to improve the characteristics of the thermal stability and / or chemical stability of that pigment. In practice, due to this improved thermal stability, each encapsulated pigment can maintain its complete crystal structure even when the temperature of the medium in which it is present rises to the enamel firing temperature.

[0022] Such pigments are preferably bright or vivid colors such as red, yellow, orange, green, pink, or blue, and their variations. "Bright color" refers to a strong color having an optical shape measured at d:0° (in accordance with CIE No. 15, ISO 7724 / 1, DIN 5033 Teil 7, ASTM E-1164) with an observer angle of 10° and an L* component greater than 40 in the CIELAB color space in the standard light source D65 transmission mode. It should be noted that CIELAB is the 1976 CIEL*a*b* color space, which is particularly used to indicate the characteristics of surface colors.

[0023] In this embodiment of the present invention, these coloring pigments are inorganic pigments. More specifically, these pigments are non-toxic inorganic pigments. Such pigments belong, but are not limited to, the (oxy)nitride group, the cerium sulfide group, or the phosphate group. It should be noted that pigments from the (oxy)nitride group are typically bright colors ranging from red to green and blue to yellow. Pigments belonging to the cerium sulfide group are basically bright colors ranging from red to orange. Pigments from the phosphate group have bright blue, green, or purple colors.

[0024] This encapsulation substep 24 includes a process of forming / coating a homogeneous compatible material layer made of a metal oxide over the entire surface of each pigment. To this end, the material is deposited on the surface at least once to form such a layer. In this respect, the layer forms a protective shell that encapsulates each pigment. It is understood that the cycle of depositing this material onto this surface can be set to obtain a predetermined thickness of this layer. In practice, the thickness of the layer can vary depending on the properties of the colorless enamel formulation to be applied to the watch component 2 and / or the properties of the colored enamel plating.

[0025] It is understood that such layers are naturally transparent so as not to alter the original color of the light-colored pigments.

[0026] The metal oxides constituting the homogeneous compatible material layer may, in a non-limiting and non-exclusive manner, be silicon dioxide (chemical formula SiO2), aluminum oxide (chemical formula Al2O3), zinc oxide (chemical formula ZnO), or titanium oxide (chemical formula TiO2).

[0027] In this encapsulation substep 24, for example, a technique for depositing at least one atomic layer, commonly known as ALD (atomic layer deposition), can be used to form the layer and thus the protective shell that encapsulates each pigment. In relation to the present invention, this technique makes it possible to deposit a thin layer on the surface of each colored pigment by a chain reaction in the gas phase using a metal oxide precursor such as trimethylaluminum when the metal oxide is aluminum oxide.

[0028] In one embodiment, the layers encapsulating each pigment can be formed using microemulsion technology. This technology allows for the deposition of metal oxides on the surface of the pigments by a microemulsion reaction using the metal oxide precursor. In relation to the present invention, this precursor may be tetraethyl orthosilicate when the metal oxide is silicon dioxide.

[0029] In another modification, the layers encapsulating each pigment can be formed using a combination of these two techniques. For example, this formation can begin with the use of ALD technology and continue with microemulsion technology, but is not limited to this.

[0030] It is understood that such substep 24 is used to encapsulate each pigment within a protective shell formed by a transparent material layer contained on the surface of the pigment. Such a layer is • Its homogeneity, • Its suitability, • Thickness of 2 nm to 1,000 nm, preferably 10 nm, preferably 30 nm, or preferably 50 nm. • Its rigidity, and / or • Transparency It is characterized by the following.

[0031] This layer, and therefore the shell, simultaneously, Oxidation at enamel firing temperature, • Acidic media, especially weakly acidic media with a pH of approximately 4.5. • Exposure to ultraviolet light, • Cosmetic products It should also be noted that this provides effective protection for coloring pigments against [unspecified element].

[0032] The preparation step 22 of the colored enamel composition also includes a mixing substep 25, in which the encapsulated colored pigment is mixed with the colorless enamel composition. This mixing substep 25 is used to obtain a colored enamel composition in which the encapsulated colored pigment is dispersed. In this substep 25, the resulting mixture corresponding to the colored enamel composition contains up to 30% or up to 50% by mass of encapsulated colored pigment.

[0033] This mass percentage is preferably between 2% and 30%.

[0034] Such mass percentages are preferably between 5% and 30%.

[0035] Such a mass percentage is preferably 5% to 10%.

[0036] It is understood that these mass percentages of coloring pigments play a role in achieving a compromise between color, transparency, and color intensity in this mixture while ensuring good final properties (e.g., mechanical properties, homogeneity, etc.).

[0037] It should also be noted that this mixture can be produced by wet mixing or any other mixing method known to those skilled in the art.

[0038] The method then includes a treatment step 26 for the receiving region 8 of the substrate to which the colored enamel plating is to be performed. In such a step 26, a degreasing agent and / or adhesive may be applied to the receiving region 8 which is intended to receive the plating 10.

[0039] The method then includes a coating step 27, in which at least one layer of the colored enamel composition thus prepared is applied to a receptive area 8 of the substrate. The receptive area 8 is understood to be, for example, all or part of the visible surface 9 of the watch part 2 when the watch part 2 is attached to the watch 1. In this step 27, the layer of colored enamel composition may be deposited on the receptive area 8 by grinding, spraying and / or printing.

[0040] The method then includes a firing step 28, in which at least one of the colored enamel compositions contained in the receiving region 8 of the substrate is fired. In this step, the substrate is fired at a temperature of 300 to 1,200 degrees, preferably 500 to 800 degrees, preferably 690 degrees, for a residence time of 1 to 10 minutes, preferably 5 minutes. This firing step 28 is carried out in air or in a controlled atmosphere, for example, under argon, nitrogen, or vacuum.

[0041] Step 28 may include a drying substep 29, in which the layer of colored enamel composition covering the receiving area 8 of the substrate is dried before firing. Such a substep 29 is used to remove moisture present in the layer before firing. All conventional drying methods can be used, such as air drying, oven drying, or radiation drying.

[0042] It should be noted that the sequence of coating step 27 and firing step 28 in the method can be repeated as needed to obtain a colored enamel plating of a specific or desired thickness on the image receiving area 8 and the watch component 2. In this regard, the thickness is determined by the number of layers constituting the colored enamel plating 8. It is understood that this thickness is determined in accordance with the characteristics of the colored enamel plating obtained, particularly its aesthetic characteristics, on the watch component 2.

[0043] The method also includes a finishing / finishing step 30 on a substrate applied to the image area for a layer of fired colored enamel composition to obtain the watch part 2 having a colored enamel plating 10. Thus, this step 30 may include a stone-cutting substep 31 on the substrate, in particular the layer of fired colored enamel composition. This substep 31 may be carried out until a desired uniform thickness of the colored enamel plating 10 is obtained. This step 30 may also then include a polishing or textured substep 32 in which the substrate, in particular the layer of fired colored enamel composition that has lost its shine during the stone-cutting substep 31, is polished or textured.

[0044] Step 30 may also include a machining substep 33 for cutting the base material for mounting to the clock 1, if necessary.

[0045] If this watch component is the dial 2, it should be noted that machining can be performed on the dial 2 to form through-holes into which the drive shafts of the hands 3a to 3c can be inserted. In this regard, appliqué / index creation can also be performed if it has not yet been done. These appliqués can be drawn, stamped, or glued directly onto the visible surface, or they can be glued by a component that penetrates the dial 2 using holes formed during machining.

[0046] The above description relates to preferred embodiments and should not be interpreted as limiting in any way, particularly with respect to the types of coloring pigments used to color the enamel. In fact, coloring pigments other than light-colored pigments are also part of the present invention. [Explanation of Symbols]

[0047] 1 Clock 2. Watch parts such as dials 3a hour hand 3b minute hand 3c second hand 4-hour marker 5-hour time display (yen) 6 openings Disk dated 7 8. Substrate and receiving area of ​​watch components 9. Visible surface of watch components 10. Colored enamel coating

Claims

1. A method for manufacturing a watch component (2) including a colored enamel coating (10), - A step (20) of providing a substrate selected from materials that can withstand the enamel firing temperature, - A step (22) for formulating a colored enamel composition that constitutes the colored enamel coating (10) of the watch component (2), comprising a formulation step (22) including an encapsulation substep (24) of encapsulating a colored pigment in a transparent protective shell made of an inorganic material, and a mixing substep (25) of mixing the encapsulated colored pigment with the enamel formulation, - Step (27) of applying at least one layer of the formulated colored enamel composition to the receiving area (8) on the substrate, - A step (28) of firing the layer of the colored enamel composition contained in the receiving region (8) A method that includes this.

2. The method according to claim 1, wherein in the encapsulation substep (24), a process for forming a homogeneous compatible material layer made of a metal oxide is applied to the entire surface of each of the colored pigments.

3. The method according to claim 2, wherein the process is carried out using ALD technology and / or microemulsion technology.

4. The method according to claim 1, wherein the colored enamel composition comprises the colored pigment encapsulated in a mass percentage of up to 30%.

5. The method according to claim 1, wherein the colored enamel composition comprises the colored pigment encapsulated in a mass percentage of up to 50%.

6. The method according to claim 1, comprising a processing step (26) for the receiving region (8) on a substrate to which a layer of the colored enamel composition is applied, wherein the processing step (26) includes applying a degreasing agent and / or adhesive to the receiving region (8).

7. The method according to claim 1, comprising a finishing / finishing step (30) performed on a substrate in a region (8) that receives a layer of the colored enamel composition, wherein the finishing / finishing step (30) comprises a stone cutting substep (31) and a polishing substep (32).

8. The method according to claim 1, wherein each of the coloring pigments is a pigment belonging to the nitride group, oxynitride group, cerium sulfide group, or phosphate group.

9. The method according to claim 1, wherein each of the coloring pigments is an inorganic pigment or a non-toxic inorganic pigment.

10. A clock component (2), A base material selected from materials configured to withstand enamel firing temperatures, A colored enamel coating (10) is provided on the receiving region (8) of the substrate and Equipped with, The aforementioned colored enamel coating (10) includes a watch component (2) comprising an enamel layer in which colored pigments are dispersed within a transparent protective shell made of inorganic material.

11. The transparent protective shell made of the inorganic material is a homogeneous compatible material layer made of a metal oxide, The metal oxide is silicon dioxide, aluminum oxide, zinc oxide, or titanium oxide. Each of the aforementioned coloring pigments is a pigment belonging to the nitride group, oxynitride group, cerium sulfide group, or phosphate group. Each of the aforementioned coloring pigments is an inorganic pigment or a non-toxic inorganic pigment, as described in claim 10 (2).

12. The watch component (2) according to claim 10, wherein the colored enamel coating (10) forms a decorative element.

13. A clock (1) including the clock component (2) described in claim 10.

Images