Watch or jewelry component and method for manufacturing such a component

Description

technical field

[0001] The present invention relates to watch or jewelry components based on elastomers. The invention also relates to a method for manufacturing such components.

[0002] In the present invention, a watch or jewelry component refers to any component used in watchmaking or jewelry making, as well as any decorative object. More particularly, the invention relates to bracelets, such as watch straps, bezels, pushers, or watch crowns. State of the art

[0003] It is already known that certain components used in jewelry, and more specifically in watchmaking, can be made from a composition containing elastomers. For example, EP 3 178 875 describes watch straps or components made from an elastomeric material comprising an elastomer, microfibers, and other fillers. The elastomer is the predominant component and is of the vulcanizable or thermoplastic type. Such elastomers are relatively expensive. Furthermore, the use of a large quantity of elastomer in the manufacture of these components makes it difficult for the manufacturer to implement an effective environmental management system, such as that required by the ISO 14001 standard.

[0004] The present invention aims to remedy these drawbacks by proposing a watch or jewelry component based on known elastomeric materials while being more economical and advantageous for environmental standards, and without being at the expense of the properties obtained with said known elastomeric materials. Disclosure of the invention

[0005] For this purpose, the invention relates to a watch or jewelry component at least partially made of an elastomeric material comprising, in relation to its total weight, at least 50% by weight of at least one elastomer and less than 50% by weight of at least one elastomeric powder derived from elastomeric waste and chemically compatible with said elastomer.

[0006] Such an elastomeric material makes it advantageous to recycle elastomeric waste and to obtain an economical and ecological watch or jewelry component, meeting current environmental standards, while exhibiting mechanical properties (resistance to friction, tensile strength, elongation, etc.) identical to those of components made of traditional elastomers.

[0007] The resulting watch or jewelry components also exhibit UV resistance identical to that of components made from traditional elastomers and do not present any irritation problems on contact with the skin.

[0008] The resulting watch or jewelry components can also exhibit visual effects that are difficult to achieve with traditional elastomers.

[0009] According to a first embodiment, said elastomeric material comprises said elastomer in the form of a layer, said elastomeric powder being present essentially on the surface of said layer.

[0010] According to a second embodiment, the elastomeric material comprises said elastomer in the form of an elastomeric matrix, and said elastomeric powder is a micropowder obtained from the micronization of elastomeric waste incorporated into the elastomeric matrix, said elastomeric material being obtained from a composition comprising at least 50% by weight of said elastomer forming the elastomeric matrix and less than 50% by weight of said elastomeric micropowder relative to the total weight of the composition.

[0011] The present invention also relates to a method for manufacturing a watch or jewelry component according to the first embodiment as defined above and comprising the following steps: a) produce a semi-finished watch or jewelry component having at least one layer of said elastomer; b) deposit said elastomer powder on said layer of said elastomer of the semi-finished watch or jewelry component obtained in step a); c) produce the watch or jewelry component by compression of the semi-finished watch or jewelry component obtained in step b).

[0012] The present invention also relates to a method for manufacturing a watch or jewelry component according to the second embodiment as defined above and comprising the following steps: d) prepare a mixture from said elastomer intended to form the elastomer matrix; e) add to the mixture obtained in step d) at least said elastomer powder in the form of an elastomer micropowder obtained from the micronization of elastomer waste and chemically compatible with said elastomer so as to obtain a composition comprising at least 50% by weight of said elastomer and less than 50% by weight of said elastomer micropowder relative to the total weight of the composition; f) produce a watch or jewelry component by injection molding of the composition obtained in step e).

[0013] Regardless of the embodiment, said elastomer may be a crosslinkable elastomer, preferably vulcanizable, said elastomer being chosen from the group comprising fluoroelastomers (FKM), butadiene-acrylonitrile copolymers (NBR), hydrogenated nitrile rubbers (HNBR), and ethylene-propylene-diene terpolymers (EPDM).

[0014] According to another possibility, the elastomer may be a thermoplastic elastomer chosen from the group including thermoplastic polyurethane elastomers, thermoplastic copolyamides, thermoplastic copolyesters, and styrenic thermoplastic elastomers.

[0015] Advantageously, said elastomer powder is of the same chemical nature as the elastomer.

[0016] Other features and advantages of the present invention will become apparent from the following detailed description of several embodiments of the invention, given by way of non-limiting examples. Method(s) of embodiment of the invention

[0017] According to the invention, the watch or jewelry component is at least partially made of an elastomeric material comprising, in relation to its total weight, at least 50% by weight of at least one elastomer and less than 50% by weight of at least one elastomeric powder derived from elastomeric waste and chemically compatible with said elastomer.

[0018] The watch or jewelry component according to the invention may, for example, constitute a bracelet, a bezel, a pusher, a crown, etc.

[0019] According to a first embodiment, said elastomeric material comprises said elastomer in the form of a layer, said elastomeric powder being present essentially on the surface of said layer.

[0020] According to a second embodiment, said elastomeric material comprises said elastomer in the form of an elastomeric matrix, and said elastomeric powder is a micropowder obtained from the micronization of elastomeric waste incorporated or dispersed in the elastomeric matrix, said elastomeric material being obtained from a composition comprising at least 50% by weight of said elastomer forming the elastomeric matrix and less than 50% by weight of said elastomeric micropowder relative to the total weight of the composition.

[0021] Advantageously, said elastomer powder can be obtained from recycled elastomer waste, recovered and reduced into elastomer granules that can be used as powder in the first embodiment.

[0022] The elastomer micropowder is obtained from recycled elastomer waste, recovered and micronized by being reduced first into granules and then into micropowder or powder with the appropriate particle size for the invention.

[0023] For this purpose, the material to be recycled from elastomeric waste, for example, vulcanized FKM waste, is identified and checked, then reduced in size by powerful granulators and crushers. The material size varies from 2.5 to 30 mm, with 4 to 6 mm being the most common value; the largest pieces of material circulate within the system, passing continuously through numerous knives until they reach the required size, before falling into a collection basket. At the outlet, a vibrating screen separates and sorts the material. Very powerful magnets are positioned at all points where the material passes to ensure the complete removal of all metallic particles. At this stage, the resulting material is in the form of elastomeric granules that can be used as powder in the first embodiment.Once the granules are produced, they are transformed into elastomer powder or micro-powder that can be used in the first or second embodiment.

[0024] According to another process, the said elastomer powder can also be obtained by removing material from recycled elastomer waste, for example by rubbing with a belt sander.

[0025] The said elastomer powder or elastomer micropowder is, for example, a powder or a powderette derived from recycled waste of fluoroelastomers (FKM), butadiene-acrylonitrile copolymers (NBR), hydrogenated nitrile rubbers (HNBR), and ethylene-propylene-diene terpolymers (EPDM), or from thermoplastic elastomer waste, such as thermoplastic polyurethane elastomer waste, thermoplastic copolyamide, thermoplastic copolyester, styrenic thermoplastic elastomer, or mixtures of a thermoplastic polymer and a vulcanized or non-vulcanized elastomer.

[0026] Depending on the manufacturing process, the elastomer powder can be in the form of coarse grains, or even flakes, with a size on the order of millimeters. Advantageously, the elastomer powder used in the first embodiment preferably consists of particles smaller than 300 µm, and more preferably smaller than 250 µm. Such a particle size makes it possible to obtain a watch or jewelry component that is pleasant to the touch.

[0027] Advantageously, the elastomeric micropowder preferably consists of particles smaller than 200 µm, and more preferably smaller than 130 µm. A micropowder with such particle size ensures good homogeneity in the composition when used in the second embodiment. Such a micropowder can also be used in the first embodiment.

[0028] A person skilled in the art will choose elastomeric powders or micropowders with sufficient particle size to obtain sufficient visibility of said powders or micropowders, and to increase contrasts.

[0029] Preferably, the elastomeric material comprises less than 30%, and more preferably less than 15%, by weight of said elastomeric powder or said elastomeric micropowder relative to its total weight.

[0030] In particular in the first embodiment, the quantity of elastomer powder or elastomer micropowder is preferably less than 5% by weight, more preferably less than 2% by weight.

[0031] In particular, in the second embodiment of the invention, excessively high concentrations of micropowder in the elastomeric material composition affect the final result, for example, by altering the color compared to an elastomeric material not containing micropowder derived from recycled elastomers. Excessive concentrations of micropowder in the composition also affect the vulcanization time when vulcanizable elastomers are used to form the elastomeric matrix.

[0032] Regardless of the embodiment described above, the elastomer used predominantly in the elastomeric material can be a crosslinkable elastomer, preferably vulcanizable.

[0033] Advantageously, the crosslinkable elastomer can be a hot-vulcanizable elastomer selected from the group comprising fluoroelastomers (FKM), butadiene-acrylonitrile copolymers (NBR), hydrogenated nitrile rubbers (HNBR), ethylene-propylene-diene terpolymers (EPDM), and silicones. Vulcanization with a sulfur system can be carried out for NBR, HNBR, and EPDM elastomers. Vulcanization with a peroxide can be carried out for FKM, HNBR, and EPDM elastomers. Vulcanization with bisphenol systems can be carried out for FKM elastomers.

[0034] Advantageously, said crosslinkable elastomer can be a cold vulcanizable elastomer such as silicones.

[0035] Regardless of the embodiment described above, the elastomer used predominantly in the elastomeric material can also be a thermoplastic elastomer (TPE).

[0036] Advantageously, the thermoplastic elastomer is selected from the group comprising a thermoplastic polyurethane (TPU) elastomer, a thermoplastic copolyamide (TPA), such as an ether-amide block copolymer, a thermoplastic copolyester (TPC), a styrenic thermoplastic elastomer (TPS), or a mechanical blend of a thermoplastic polymer and a vulcanized (TPV) or non-vulcanized (TPO) elastomer.

[0037] Preferably, the elastomer powder or micropowder used is of the same chemical nature as the elastomer predominantly used in the elastomer material. For example, for an FKM elastomer, an FKM powder or micropowder is used. For an NBR or HNBR elastomer, an NBR or HNBR powder or micropowder is used. For an EPDM elastomer, an EPDM powder or micropowder is used.

[0038] The hardness of the elastomer material can range from 30 Shore A to 90 Shore A, inclusive. More specifically, when the resulting watch component is a strap, the hardness of the elastomer material can range from 60 Shore A to 80 Shore A, inclusive. When the resulting watch component is a pusher or crown, the hardness of the elastomer material can range from 30 Shore A to 90 Shore A, inclusive.

[0039] Shore hardness, which is a material constant applicable to certain plastics and elastomers, is defined in the DIN 53505 and DIN EN ISO 868 standards. The Shore A test is indicated for soft elastomers after measurement using a blunt-tipped needle.

[0040] Depending on the embodiment, the composition intended to obtain the elastomeric material may further include a coloring agent, such as a dye and / or pigment, which may be in powder or liquid form. The quantity of coloring agent may be between 0% and 15% by weight relative to the total weight of the composition.

[0041] The composition used to obtain the elastomer material may also include crosslinking or vulcanizing agents specific to the elastomer, and other traditional additives commonly used by those skilled in the art in the field of crosslinkable elastomer formulations, and more particularly in formulations based on vulcanizable elastomers. The crosslinking or vulcanizing agents may be of the peroxide, sulfur, or bisphenol type, with the concentration optimized according to practices known to those skilled in the art.

[0042] The composition intended to obtain the elastomer material may also include other components, such as fillers, processing agents, etc.

[0043] The invention also relates to a method for manufacturing a watch or jewelry component at least partially made of an elastomeric material comprising, relative to its total weight, at least 50% by weight of at least one elastomer and less than 50% by weight of at least one elastomeric powder derived from elastomeric waste and chemically compatible with the elastomer according to the first embodiment described above, comprising the following steps: a) produce a semi-finished watch or jewelry component having at least one layer of said elastomer; b) deposit, for example by sprinkling, said elastomer powder on said layer of said elastomer of the semi-finished watch or jewelry component obtained in step a); c) produce the watch or jewelry component by compressing the semi-finished watch or jewelry component obtained in step b).

[0044] The invention also relates to a method for manufacturing a watch or jewelry component at least partially made of an elastomeric material comprising, relative to its total weight, at least 50% by weight of at least one elastomer and less than 50% by weight of at least one elastomeric micropowder obtained from the micronization of elastomeric waste and chemically compatible with the elastomer according to the second embodiment described above, comprising the following steps: d) prepare a mixture from said elastomer intended to form the elastomer matrix; e) add to the mixture obtained in step d) at least said elastomer micropowder obtained from the micronization of elastomer waste and chemically compatible with said elastomer so as to obtain a composition comprising at least 50% by weight of said elastomer and less than 50%, preferably less than 30%, and more preferably less than 15%, by weight of said elastomer micropowder relative to the total weight of the composition; f) produce a watch or jewelry component by injection molding of the composition obtained in step e) to obtain the desired shape.

[0045] Depending on the intended applications for the watch or jewelry component, the elastomer intended to form the elastomer matrix is ​​a crosslinkable elastomer, preferably vulcanizable, or a thermoplastic elastomer, as described above.

[0046] Preferably, a person skilled in the art chooses an elastomer powder or elastomer micropowder of the same chemical nature as the elastomer used predominantly in the elastomer material.

[0047] With regard to the second embodiment in particular, to facilitate mixing, when the elastomers are for example FKM elastomers, said elastomers have a low viscosity.

[0048] During step e), said micropowder from recycled elastomers can advantageously be incorporated into a standard formula of the mixture obtained in step d), as a filler, without having to modify, for example, the composition of the vulcanization system.

[0049] For the production of colored watch or jewelry components, the mixture used in step d) is preferably neutral and colorless, and the elastomeric micropowder added in step e) is preferably pre-colored. Other coloring agents, such as pigments, can then be added to color the elastomeric matrix. Aesthetic visual effects can thus be advantageously achieved by using one or more elastomeric micropowders in colors different from that of the elastomeric matrix.

[0050] Step f) of molding the composition obtained in step e) is carried out by injection. When a vulcanizable elastomer is used for the elastomer matrix, vulcanization is carried out in a known manner at a temperature generally between 150°C and 200°C, for a sufficient time which may vary depending on the part, in particular depending on the curing temperature, the vulcanization system adopted and the vulcanization kinetics of the composition.

[0051] Depending on the application, step c) or step f) may possibly be followed by an additional overmolding step or by finishing steps of the component obtained in step c) or step f).

[0052] It is quite clear that the first and second embodiments can be combined. An elastomer powder can indeed be deposited on the surface of an elastomer material which comprises an elastomer in the form of an elastomer matrix and an elastomer micropowder resulting from the micronization of elastomer waste incorporated into said elastomer matrix, the whole being then compressed.

[0053] Advantageously, the use according to the invention of elastomer powder or elastomer micropowder derived from recycled elastomer waste makes it possible to obtain an economical and ecological watch or jewelry component, allowing compliance with environmental standards.

[0054] Furthermore, the use of such elastomer powder or elastomer micropowder does not affect the mechanical properties of the resulting watch or jewelry component, such as resistance to dry or wet friction (ISO 11340 / ISO 11341 standard), tensile strength, and elongation. The dimensions of the parts are maintained during their manufacture.

[0055] The resulting watch or jewelry components also exhibit UV resistance identical to that of components made from traditional elastomers and present no irritation problems on contact with the skin.

[0056] In a process involving an overmolding step, the resulting elastomer material advantageously exhibits good adhesion to plastic (PA polyamides, PPA polyphthalamides) or metallic (titanium, steel) inserts through the use of standard bonding agents selected for a specific elastomer / substrate combination. For example, CHEMOSIL 411 can be used for an EPDM / metal combination.

Claims

1. A timepiece or jewellery component, characterised in that it is at least partially produced from an elastomer material comprising, with respect to its total weight, at least 50% by weight of at least one elastomer and less than 50% by weight of at least one elastomer powder originating from elastomer waste and chemically compatible with said elastomer.

2. The timepiece or jewellery component according to Claim 1, characterised in that said elastomer material comprises less than 30%, and preferably less than 15%, by weight of elastomer powder with respect to its total weight.

3. The timepiece or jewellery component according to any one of the preceding claims, characterised in that the elastomer is a crosslinkable, preferably vulcanisable, elastomer.

4. The timepiece or jewellery component according to Claim 3, characterised in that said crosslinkable elastomer is selected from the group comprising the fluoroelastomers (FKM), the butadiene-acrylonitrile copolymers (NBR), the hydrogenated nitrile rubbers (HNBR), and the ethylene-propylene-diene terpolymers (EPDM).

5. The timepiece or jewellery component according to any one of Claims 1 to 2, characterised in that the elastomer is a thermoplastic elastomer.

6. The timepiece or jewellery component according to Claim 5, characterised in that the thermoplastic elastomer is selected from the group comprising the thermoplastic polyurethane elastomers, the thermoplastic copolyamides, the thermoplastic copolyesters, and the thermoplastic styrene elastomers.

7. The timepiece or jewellery component according to any one of the preceding claims, characterised in that the elastomer powder is of the same chemical nature as the elastomer.

8. The timepiece or jewellery component according to any one of the preceding claims, characterised in that the composition furthermore comprises a colouring agent.

9. The timepiece or jewellery component according to any one of the preceding claims, characterised in that the composition furthermore comprises crosslinking agents.

10. The timepiece or jewellery component according to any one of the preceding claims, characterised in that it constitutes a strap, a bezel, a pushbutton, a crown.

11. The timepiece or jewellery component according to any one of the preceding claims, characterised in that said elastomer material comprises said elastomer in the form of a layer, said elastomer powder being present on the surface of said layer.

12. The timepiece or jewellery component according to any one of Claims 1 to 10, characterised in that said elastomer material comprises said elastomer in the form of an elastomer matrix, and in that said elastomer powder is a micropowder originating from the micronisation of elastomer waste incorporated into the elastomer matrix, said elastomer material being obtained from a composition comprising at least 50% by weight of said elastomer forming the elastomer matrix and less than 50% by weight of said elastomer micropowder with respect to the total weight of the composition.

13. The timepiece or jewellery component according to any one of the preceding claims, characterised in that the elastomer powder is a micropowder originating from the micronisation of elastomer waste and composed of particles of sizes preferably less than 200 µm, more preferably less than 130 µm.

14. A method for manufacturing a timepiece or jewellery component at least partially produced from an elastomer material comprising, with respect to its total weight, at least 50% by weight of at least one elastomer and less than 50% by weight of at least one elastomer powder originating from elastomer waste and chemically compatible with the elastomer according to Claim 11, characterised in that it comprises the following steps of: a) producing a semi-finished timepiece or jewellery component having at least one layer of said elastomer; b) placing said elastomer powder on said layer of said elastomer of the semi-finished timepiece or jewellery component obtained in step a); c) producing the timepiece or jewellery component by compressing the semi-finished timepiece or jewellery component obtained in step b).

15. The method for manufacturing a timepiece or jewellery component at least partially produced from an elastomer material comprising, with respect to its total weight, at least 50% by weight of at least one elastomer and less than 50% by weight of at least one elastomer micropowder originating from the micronisation of elastomer waste and chemically compatible with the elastomer according to Claim 12, characterised in that it comprises the following steps of: d) producing a mixture from said elastomer intended to form the elastomer matrix; e) adding at least said elastomer micropowder to the mixture obtained in step d) so as to obtain a composition comprising at least 50% by weight of said elastomer and less than 50% by weight of said elastomer micropowder with respect to the total weight of the composition; f) producing a timepiece or jewellery component by injection moulding of the composition obtained in step e).

16. The method according to any one of Claims 14 and 15, characterised in that the elastomer material comprises less than 30%, and preferably less than 15%, by weight of elastomer powder with respect to its total weight.

17. The method according to any one of Claims 14 to 16, characterised in that the elastomer is a crosslinkable, preferably vulcanisable, elastomer, or a thermoplastic elastomer.

18. The method according to any one of Claims 14 to 17, characterised in that the elastomer powder is of the same chemical nature as the elastomer.

19. The method according to any one of Claims 14 to 18, characterised in that the elastomer powder is a micropowder originating from the micronisation of elastomer waste and composed of particles of sizes preferably less than 200 µm, more preferably less than 130 µm.

20. The method according to any one of Claims 14 to 19, characterised in that the composition furthermore comprises a colouring agent.

21. The method according to any one of Claims 14 to 20, characterised in that the composition furthermore comprises crosslinking agents.