A method for coating exterior parts, particularly in the field of timepieces, and the coated exterior parts

Abstract

To provide a coating method that protects a timepiece external part against damage that could be caused thereto during manufacture and assembly.SOLUTION: A method of coating an external part 1 used in the horology, fashion, jewelry, and gemstone jewelry fields is provided, the method comprising at least partially overmolding the external part 1 with an overmolding layer 4 made of a plastic polymer material selected from a group consisting of thermoplastic polymers of the polyurethane family and thermosetting polymers of the epoxy polymer family, or from a group consisting of thermoplastic acrylic resins.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for coating exterior parts used in the fields of horology, fashion items, jewellery and gem processing. [Background technology]

[0002] The present invention relates to the field of exterior parts used in the fields of horology, fashion items, jewellery and gem-making.

[0003] In the following description, the term "fashion item" refers to clothing and accessories such as belts, footwear, and clothing, as well as eyewear, electronic devices, for example phones, and any other decorative items.

[0004] Furthermore, the term "external part" is commonly used in the abovementioned fields to refer to a component that is visible to the user and has a decorative function, i.e., contributes to the visual appearance of an object.

[0005] In the specific field of horology, one well-known category of exterior parts is the watch dial, on which move the hands that display, among other things, the current time, and which often also receives technical parts such as hour indexes, sometimes made of brilliant-cut stones, or decorative parts such as the logotype of the watch brand.

[0006] These dials are very expensive and particularly fragile. However, a lot of work is done on this type of dial during its manufacture and installation in the watch case. As a result, there is a high risk that these dials will deteriorate and have to be discarded, which is unacceptable from an economic point of view.

[0007] Therefore, there has been a need in the prior art to protect any type of exterior part in the fields of horology, fashion items, jewelry, and gemstone processing from damage that may occur to the exterior part during manufacturing and assembly. Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to overcome the above-mentioned and other drawbacks by proposing a method for coating external parts in the fields of horology, fashion items, jewellery and gem-making to ensure effective mechanical protection of these external parts against the external mechanical stresses to which they may be subjected, in particular during their manufacture and during the assembly of the watch. [Means for solving the problem]

[0009] For this purpose, the invention relates to a method for coating exterior parts used in the fields of horology, fashion items, jewellery and gem processing, which method comprises the following steps: - at least partially overmolding said exterior part with an overmolding layer made of a plastic polymer material selected from the group consisting of thermoplastic polymers of the polyurethane series and thermosetting polymers of the epoxy polymer series or from the group consisting of thermoplastic acrylic resins. Includes.

[0010] According to one particular embodiment of the invention, the method further comprises the step of replicating a pattern in the overmolded layer, which is at least partially overmolded onto the exterior part.

[0011] According to another particular embodiment of the invention, said step of at least partially overmolding said exterior part is carried out by molding or injection of said plastic polymer material.

[0012] According to yet another particular embodiment of the present invention, the at least partial overmolding of the exterior part comprises the following steps: - placing said exterior part in a mould containing said pattern to be replicated in said overmold layer, which is at least partially overmolded onto said exterior part; - closing the mould; - injecting said plastic polymer material into said mould so that said plastic polymer material forms an overmold layer at least partially overmolds said exterior part and at the same time said pattern is replicated in said overmold layer; - opening the mould and removing the overmolded exterior part from the mould. Includes.

[0013] According to yet another particular embodiment of the invention, said mould is made of a silicone material or of a metal or ceramic material.

[0014] According to yet another particular embodiment of the present invention, when the mold is made of a silicone material, the silicone mold containing the pattern designed to be replicated in the overmolded layer is made by a male master mold that carries the pattern designed to be replicated in the overmolded layer.

[0015] According to yet another particular embodiment of the invention, when the mold is made of a silicone, metal or ceramic material, the pattern contained in the metal or ceramic mold and designed to be replicated in the overmolding layer is formed using a laser beam device, by means of which the pattern designed to be replicated in the overmolding layer is formed as a negative mold in the metal or ceramic mold.

[0016] According to yet another particular embodiment of the invention, the step of at least partially overmolding the exterior part consists of coating the exterior part with an overmolding layer formed by spraying the plastic polymer material onto the exterior part, and subsequently replicating the pattern in the overmolding layer at high temperature by a tool holding a negative version of the pattern designed to be replicated in the overmolding layer, created by means of a laser beam device.

[0017] According to yet another particular embodiment of the invention, said overmold layer is obtained by depositing said plastic polymer material in one or more successive applications.

[0018] According to yet another particular embodiment of the invention, the thickness of said overmolding layer is 100 μm±10%.

[0019] According to yet another particular embodiment of the invention, the laser beam device used to form the pattern comprises a laser beam emitting a coherent beam having short pulses in the nanosecond range or having ultrashort pulses in the picosecond to femtosecond range.

[0020] According to yet another particular embodiment of the invention, the laser beam emits pulses with an adjustable duration between 4 ns and 350 ns, a frequency between 10 kHz and 1 MHz and a power of 40 W or close to 40 W.

[0021] According to yet another particular embodiment of the present invention, when the laser beam emits ultrashort pulses, the pulse frequency is between 100 kHz and 100 MHz.

[0022] According to yet another particular embodiment of the invention, said overmold layer performs the technical role of providing mechanical protection and, optionally, a decorative role.

[0023] According to yet another particular embodiment of the present invention, the overmold layer comprises 78% by weight of a plastic polymer, 15% by weight of a carbon black colorant, 5% by weight of graphene, and 2% by weight of a binder to promote adhesion of the overmold layer to the exterior component.

[0024] According to yet another specific embodiment of the present invention, the overmold layer comprises 30% by weight of a thermoplastic acrylic resin and 60% by weight of a solvent to which is added 1% by weight of a dispersant, 8% by weight of a black colorant, and 1% by weight of a binder to promote adhesion of the overmold layer to the exterior component.

[0025] According to yet another particular embodiment of the invention, said coupling agent is a silane.

[0026] According to yet another particular embodiment of the present invention, said black colorant has a lightness value of 10 or less as measured by colorimetry.

[0027] According to yet another particular embodiment of the invention, the black colorant is composed of 95% by weight of carbon black and 5% by weight of graphene.

[0028] The invention further relates to an exterior part in the field of horology, fashion items, jewellery and gem processing, which is at least partially coated with an overmold layer made of a plastic polymer material selected from the group consisting of thermoplastic polymers of the polyurethane series and thermosetting polymers of the epoxy polymer series or from the group consisting of thermoplastic acrylic resins.

[0029] According to one particular embodiment of the invention, said overmold layer comprises a decorative and / or technical pattern replica.

[0030] According to another embodiment of the invention, the overmolded layer is formed by one or more plastic polymer layers.

[0031] According to yet another embodiment of the present invention, the thickness of said overmolded layer is 100 μm±10%.

[0032] According to yet another embodiment of the invention, the overmold layer comprises 78% by weight of a plastic polymer, 15% by weight of a carbon black colorant, 5% by weight of graphene, and 2% by weight of a binder to promote adhesion of the overmold layer to the exterior component.

[0033] According to yet another embodiment of the invention, the overmold layer comprises 30% by weight of a thermoplastic acrylic resin and 60% by weight of a solvent to which is added 1% by weight of a dispersant, 8% by weight of a black colorant, and 1% by weight of a binder to promote adhesion of the overmold layer to the exterior component.

[0034] According to yet another embodiment of the present invention, the coupling agent is a silane.

[0035] According to yet another embodiment of the present invention, the black colorant has a lightness value of 10 or less as measured by colorimetry.

[0036] According to yet another embodiment of the present invention, the black colorant is composed of 95% carbon black and 5% graphene by weight.

[0037] By virtue of these characteristics, the present invention provides a method for coating exterior parts in the fields of horology, fashion items, jewellery and gem-making, which makes it possible to protect such exterior parts from damage that may occur to them during their manufacture and assembly by disclosing at least partial overmolding of said exterior parts with an overmolding layer made of a plastic polymer material.

[0038] According to another advantage of the present invention, overmolding of said exterior part with a layer of plastic polymer material can be easily implemented by spraying a number of successive thin layers of said plastic polymer material or by injecting said plastic polymer material into a mold by injection molding.

[0039] According to yet another advantage of the invention, the overmold layer coating the exterior part also contributes to the decoration of the exterior part, in particular by replicating the imprint of the pattern in the overmold layer and, if necessary, by giving it a particular appearance, for example a matt appearance, or a particular color, for example a deep black color. The overmold layer thus advantageously has two functions: the function of ensuring the mechanical protection of the exterior part and the function of decorating the exterior part overmolded with the overmold layer.

[0040] Other features and advantages of the present invention will become more apparent upon reading the detailed description given below of certain exemplary implementations of the method according to the invention, with reference to the attached drawings, in which: The above examples are provided for illustrative purposes only and are not intended to limit the scope of the invention. [Brief description of the drawings]

[0041] [Figure 1] FIG. 1 is a perspective view of a dial-type exterior part for a watch, coated with an overmolded layer. [Figure 2A] FIG. 2A is a schematic diagram showing the steps of overmolding an exterior part by spraying a plastic polymer material. [Figure 2B] FIG. 2B is a schematic diagram showing a step of replicating the pattern at high temperature into the overmolded layer using a tool holding a negative version of the pattern created using a laser beam device to be overmolded into the overmolded layer. [Diagram 3]FIG. 3 is a schematic diagram showing the steps of overmolding and replicating a pattern by injecting a plastic polymer material into a mold. [Figure 4] FIG. 4 is a schematic diagram illustrating a first method for producing a mold that includes a pattern designed to be replicated in an overmold layer that at least partially surrounds an exterior component. [Diagram 5] FIG. 5 is a schematic diagram illustrating a second method for producing a mold that includes a pattern designed to be replicated in an overmold layer that at least partially surrounds an exterior component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The present invention starts from a general inventive concept consisting in that any type of exterior part from the field of horology, fashion items, jewellery and gem processing can be protected from damage that may occur to said exterior part during production and assembly by coating it with an overmold layer made of a plastic polymer material. According to another aspect thereof, the invention further proposes to decorate the exterior part coated with said overmold layer by means of said overmold layer. In particular, said layer is designed to be given a specific colour, for example a deep black or a reflective white colour. The overmold layer according to the invention therefore has two functions, namely a mechanical protection function and a function for decorating the exterior part. These two functions are realized by the same overmold layer, which is very easily deposited by spraying a thin layer of the plastic polymer material or by injecting the plastic polymer material into a mould.

[0043] In the following description, it is assumed, by way of example only for illustrative and non-limiting purposes, that said exterior part is the dial of a timepiece, such as a wristwatch, which is designated throughout by the general reference number 1 and which is provided with a number of holes 2, in particular to allow the passage of the stems of hour and minute hands (not shown) for indicating the current time, and to allow the attachment of decorative material, for example for the formation of hour indexes (see FIG. 1 ).

[0044] According to the invention, this dial 1 is at least partially coated with an overmold layer 4 made of a plastic polymer material selected from the group consisting of thermoplastic polymers of the polyurethane family and thermosetting polymers of the epoxy polymer family or from the group consisting of thermoplastic acrylic resins.

[0045] The overmold layer 4 fulfills the technical role of providing mechanical protection. The presence of this overmold layer 4 can also be used to replicate a pattern 6 for purely decorative or even technical purposes (e.g. replicating the logotype of a watch brand). In addition to the appearance of the pattern 6 replicated in the overmold layer 4, the color of the overmold layer 4 can also be varied.

[0046] According to one particular implementation of the present invention, the overmold layer 4 comprises 78% by weight plastic polymer, 15% by weight carbon black colorant, 5% by weight graphene, and 2% by weight binder to promote adhesion of the overmold layer 4 to the exterior component 1.

[0047] According to another particular embodiment of the present invention, the overmold layer 4 comprises 30% by weight of a thermoplastic acrylic resin and 60% by weight of a solvent to which is added 1% by weight of a dispersant, 8% by weight of a black colorant, and 1% by weight of a binder to promote adhesion of the overmold layer 4 to the exterior part 1.

[0048] The binder is, for example, a silane. The black colorant is composed of 95% by weight of carbon black and 5% by weight of graphene. The black colorant preferably has a colorimetric value of 10 or less.

[0049] According to a first implementation of the method of the invention, illustrated in Fig. 2A, the step of overmolding the external part 1 consists of coating said external part 1 with an overmolding layer 4 formed by spraying said external part 1 with a plastic polymer material. This overmolding layer 4 is obtained by depositing the plastic polymer material in one or more successive applications. The thickness of the overmolding layer 4 is 100 μm ± 10%. This overmolding protects the external part 1 from the risk of degradation that may occur during its manufacture and, for example, during its assembly in a watch case if said external part is a dial.

[0050] The presence of an overmold layer 4, the purpose of which is first and foremost to protect the exterior part 1 against the risk of degradation, can also be used to form a three-dimensional pattern in said overmold layer 4, the function of which can be purely decorative or technical (for example, reproducing the logotype of a watch brand in the thickness of the overmold layer 4). For this, as shown diagrammatically in FIG. 2B, after coating the exterior part 1, the pattern 6 is reproduced at high temperature in the overmold layer 4 by means of a stamp-type tool 8. Said tool 8 can be produced, for example, by means of a laser beam device and holds a negative form of the pattern 6 to be reproduced in the overmold layer 4.

[0051] According to a second implementation of the method of the invention, shown in FIG. 3, the step of at least partially overmolding the exterior part 1 comprises the following steps: placing the exterior part 1 in a mould 10 containing a pattern 6 to be replicated in an overmoulding layer 4 which is at least partially overmoulded onto the exterior part 1; - closing the mould 10; - injecting a plastic polymer material into the mould 10 via the injection channel 12, so that it forms an overmoulding layer 4 which at least partially overmoulds the exterior part 1 and so that at the same time the pattern 6 is replicated in this overmoulding layer 4; - opening the mould 10 and removing the overmolded exterior part 1 from the mould 10; Includes.

[0052] The mold 10 is made of a silicone material or a metal or ceramic material, the silicone mold being more particularly reserved for use in the production by molding of a series of small overmolded exterior parts 1, whereas the metal or ceramic mold is preferred in the production by injection molding of a series of large overmolded exterior parts 1.

[0053] As shown in Fig. 4, when the mold 10 is made of a silicone material, multiple copies of the silicone mold 14 are often made from one master mold 16. The master mold 16 contains a pattern 6 that can be formed, for example, using a laser beam device. The pattern 6p is designed to be replicated in the silicone mold 14 and represents the male of the pattern 6 that will be replicated in the overmolding layer 4. The exterior part 1 is overmolded by molding the exterior part 1 in the silicone mold.

[0054] If the mold 10 is made of a metal or ceramic material, the pattern 6 contained in the metallic mold 18 and designed to be directly replicated in the overmolded layer 4 is formed, for example, using a laser beam device, by which the pattern 6n designed to be replicated in the overmolded layer 4 is formed as a negative mold in the inner walls of the metallic mold 18 (see FIG. 5).

[0055] The laser beam device used to form the pattern 6 in the metal mold 18 comprises a laser beam emitting a coherent beam of light with short pulses in the nanosecond range or with ultrashort pulses in the picosecond to femtosecond range.

[0056] The laser beam emits pulses with tunable duration between 4 ns and 350 ns, frequencies between 10 kHz and 1 MHz, and powers around 40 W.

[0057] When the laser beam emits an ultrashort pulse, the pulse frequency is 100 kHz to 100 MHz.

[0058] Naturally, the present invention is not limited to the above-mentioned implementations, and various simple alternatives and modifications can be considered without departing from the scope of the present invention, as defined by the appended claims. It should be noted that in particular, when the exterior part is a watch face, it is preferable not to coat the edge of the watch face with the overmolding layer 4, in order to make it easier to install the watch face in the watch case. More generally, when overmolding a given exterior part, steps can be taken to ensure that certain surfaces of the exterior part are not coated by the overmolding layer. It should also be noted that when applying the method of the present invention to exterior parts designed to contact the skin of a user, the overmolding layer provides a high level of comfort when worn. [Explanation of symbols]

[0059] 1 Exterior parts 2 holes 4 Overmolding Layer 6 Patterns 6p male pattern 6n female pattern 8 Tools 10 Mold 12 Injection Channel 14 Silicone mold 16 Master Mold 18 Metal molds

Claims

1. A method for coating exterior parts (1) used in the fields of horology, fashion items, jewellery and gem processing, said coating method comprising the following steps: - at least partially overmolding said exterior part (1) with an overmolding layer (4) made of a plastic polymer material selected from the group consisting of thermoplastic polymers of the polyurethane family and thermosetting polymers of the epoxy polymer family or from the group consisting of thermoplastic acrylic resins. A method comprising:

2. 2. The method for coating an exterior part according to claim 1, characterized in that the method further comprises the step of replicating a pattern (6) in the overmolding layer (4) which is at least partially overmolded onto the exterior part (1).

3. 3. The method for coating exterior parts according to claim 2, characterized in that the step of at least partially overmolding the exterior part (1) is carried out by molding or injection of the plastic polymer material.

4. The step of at least partially overmolding the exterior part (1) comprises the following steps: - placing said exterior part (1) in a mould containing said pattern to be replicated in said overmold layer (4) which is at least partially overmolded onto said exterior part (1); - closing the mold; - injecting said plastic polymer material into said mould so that it forms said overmold layer (4) which at least partially overmolds said exterior part (1) and at the same time so that said pattern is replicated in said overmold layer (4); - opening the mould and removing the overmolded exterior part (1) from the mould.

4. The method of claim 3, comprising:

5. 5. The method for coating exterior parts according to claim 4, characterized in that the mould is made of a silicone material or of a metal or ceramic material.

6. 6. The method for coating exterior parts according to claim 5, characterized in that, when the mold is made of a silicone material, the silicone mold (14) containing the pattern (6) designed to be replicated in the overmold layer (4) is produced by a male master mold (16) carrying the pattern (6) designed to be replicated in the overmold layer (4).

7. 6. The method for coating exterior parts according to claim 5, characterized in that, if the mould is made of a silicone, metal or ceramic material, the pattern (6) contained in the metal or ceramic mould (18) and designed to be replicated in the overmold layer (4) is formed by means of a laser beam device, by means of which the pattern (6) designed to be replicated in the overmold layer (4) is formed as a negative mould in the metal or ceramic mould (18).

8. 3. The method for coating an exterior part according to claim 2, characterized in that the step of at least partially overmolding the exterior part (1) consists of coating the exterior part (1) with an overmolding layer (4) formed by spraying the exterior part (1) with the plastic polymer material, and subsequently replicating the pattern (6) in the overmolding layer (4) at high temperature by means of a tool holding a negative version of the pattern (6) designed to be replicated in the overmolding layer (4), made by means of a laser beam device.

9. A method for coating exterior parts according to claim 8, characterized in that said overmold layer (4) is obtained by depositing said plastic polymer material in one or more successive applications.

10. 10. The method for coating exterior parts according to claim 9, characterized in that the thickness of the overmold layer (4) is 100 μm ± 10%.

11. 8. The method for coating exterior parts according to claim 7, characterized in that the laser beam device used for forming the pattern (6) comprises a laser beam emitting a coherent beam with short pulses in the nanosecond range or with ultrashort pulses in the picosecond to femtosecond range.

12. 12. The method for coating exterior parts according to claim 11, characterized in that the laser beam emits pulses with an adjustable duration between 4 ns and 350 ns, with a frequency between 10 kHz and 1 MHz and a power of 40 W or close to 40 W.

13. 12. The method for coating exterior parts according to claim 11, characterized in that when the laser beam emits ultrashort pulses, the pulse frequency is between 100 kHz and 100 MHz.

14. 3. A method for coating exterior parts according to claim 2, characterized in that the overmold layer (4) fulfills a technical role of providing mechanical protection and, if necessary, a decorative role.

15. 15. The method of coating an exterior part according to claim 14, characterized in that the overmold layer (4) comprises 78% by weight of plastic polymer, 15% by weight of carbon black pigment, 5% by weight of graphene and 2% by weight of a binder to promote adhesion of the overmold layer (4) to the exterior part (1).

16. 15. The method of coating an exterior part according to claim 14, characterized in that the overmold layer (4) comprises 30% by weight of a thermoplastic acrylic resin and 60% by weight of a solvent to which 1% by weight of a dispersant, 8% by weight of a black colorant and 1% by weight of a binder for promoting adhesion of the overmold layer (4) to the exterior part (1) are added.

17. 16. The method of coating an exterior component according to claim 15, characterized in that the bonding agent is a silane.

18. 17. The method of coating an exterior part of claim 16, wherein the black colorant has a lightness value of 10 or less as measured by colorimetry.

19. 20. The method of claim 18, wherein the black colorant is composed of 95% by weight carbon black and 5% by weight graphene.

20. An exterior part (1) in the field of horology, fashion items, jewellery and gem processing, said exterior part (1) being at least partially coated with an overmold layer (4) made of a plastic polymer material selected from the group consisting of thermoplastic polymers of the polyurethane series and thermosetting polymers of the epoxy polymer series or from the group consisting of thermoplastic acrylic resins.

21. Exterior part (1) according to claim 20, characterized in that the overmold layer (4) comprises a reproduction of a decorative and / or technical pattern (6).

22. Exterior part (1) according to claim 20, characterized in that the overmold layer (4) is formed by one or more plastic polymer layers.

23. 23. Exterior part (1) according to claim 22, characterized in that the thickness of the overmold layer (4) is 100 μm ± 10%.

24. 24. The exterior part (1) according to claim 23, characterized in that the overmold layer (4) comprises 78% by weight of plastic polymer, 15% by weight of carbon black pigment, 5% by weight of graphene and 2% by weight of a binder for promoting adhesion of the overmold layer (4) to the exterior part (1).

25. 24. The exterior part (1) according to claim 23, characterized in that the overmold layer (4) comprises 30% by weight of a thermoplastic acrylic resin and 60% by weight of a solvent to which 1% by weight of a dispersant, 8% by weight of a black colorant and 1% by weight of a binder for promoting adhesion of the overmold layer (4) to the exterior part (1) are added.

26. 25. Exterior part (1) according to claim 24, characterized in that the bonding agent is a silane.

27. 25. Exterior part (1) according to claim 24, characterized in that the black colorant has a lightness value, measured by colorimetry, of less than or equal to 10.

28. 28. Exterior part (1) according to claim 27, characterized in that the black colorant consists of 95% by weight of carbon black and 5% by weight of graphene.

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