Decorative article made of heavy composite material

Abstract

The invention relates to a decorative article made of a heavy composite material. Specifically, the invention relates to a decorative article made of a molding material having a density of 2-7 g / cm, in which the molding material comprises:-60-90% of a metal or ceramic material having a density higher than or equal to 5 g / cm,-10-32% of a plastic material comprising a thermoplastic resin and a coupling agent,-0-8% of a reinforcing material,-0-10% of a plastic material having a density higher than or equal to 5 g / cm, and-0-10% of a plastic material having a density higher than or equal to 10 g / cm. And 0-3% of a pigment. The invention also relates to a method for manufacturing such a decorative article by injection moulding.

Description

[0001] This patent application is a divisional application of patent application No. 201911346057.6, filed on December 24, 2019, with the same title. Technical Field

[0002] This invention relates to a decorative item or article, and more particularly to an external component for a watch made of a heavy, impact-resistant composite material. The invention also relates to a method of manufacturing the item. Background Technology

[0003] Many external components, such as the case middles and bracelets, are made of plastic. These components are manufactured using a molding process, which has the advantage of being able to achieve various shapes without any finishing work. These plastic components have a density close to 1, making them lightweight. This can be a disadvantage for users who prefer a watch with some weight on their wrist.

[0004] To overcome this drawback, for example, European Patent 2482142 proposes the manufacture of watch parts for movement or exterior using plastic materials reinforced with high-density metal powders such as tungsten powder. These parts are made using an injection molding process, which retains the advantages of molding in a mold without requiring any subsequent finishing, while also increasing density. Summary of the Invention

[0005] The purpose of this invention is to provide a novel heavy-duty composite material composition that meets the aesthetic and mechanical standards, particularly the durability standards, for watchmaking applications.

[0006] Therefore, the present invention provides a decorative article made of a material comprising, by weight: -60-90% metallic or ceramic material, wherein the metallic or ceramic material has a density greater than or equal to 5 g / cm³. -10-32% plastic material, said plastic material comprising thermoplastic resin or a mixture of thermoplastic resin and coupling agent, -0 to 8% reinforcement. -0% to 3% pigment.

[0007] Preferably, the material includes stainless steel as a metallic material, MABS (methyl methacrylate acrylonitrile butadiene styrene) as a thermoplastic resin, and ethylene methacrylate as a coupling agent.

[0008] Advantageously, the material includes a reinforcing material at a weight percentage of 1% or greater to increase the material's toughness and / or limit its shrinkage during the molding process. This reinforcing material can be present in various forms, such as fibers or granules.

[0009] In addition, the material may contain organic pigments, such as carbon black.

[0010] The resulting composite material has a density of 2-7 g / cm³ and high toughness.

[0011] Furthermore, the present invention relates to a method for preparing the material, which is optimized to ensure a homogeneous mixture and good compatibility among the various components of the material.

[0012] Other features and advantages of the invention will become apparent in the following description of preferred embodiments given by way of non-limiting example with reference to the accompanying drawings.

[0013] The present invention includes the following embodiments: 1. A decorative article made of a molding material with a density of 2-7 g / cm³, wherein the molding material comprises, by weight: -60-90% metallic or ceramic material, wherein the metallic or ceramic material has a density greater than or equal to 5 g / cm³. -10-32% plastic material, said plastic material comprising thermoplastic resin or a mixture of thermoplastic resin and coupling agent, -0-8% reinforcing material, -0-3% pigment.

[0014] 2. The article according to embodiment 1, characterized in that the metal material is conventional carbon steel, stainless steel, tungsten, copper or copper alloy.

[0015] 3. The article according to embodiment 1 or 2, characterized in that the metal material is stainless steel, which exists in the molding material at a weight percentage of 60-80%.

[0016] 4. The article according to embodiment 1 or 2, characterized in that the metallic material is tungsten, which is present in the molding material at a weight percentage of 65-90%.

[0017] 5. The article according to embodiment 1, characterized in that the ceramic material is zinc oxide, zirconium oxide or cerium oxide.

[0018] 6. The article according to embodiment 1, wherein the metallic material is a precious metal or a precious metal alloy.

[0019] 7. The article according to any one of the foregoing embodiments, characterized in that the metal or ceramic material is present in a weight percentage of 71-80%.

[0020] 8. The article according to any one of the foregoing embodiments, characterized in that the thermoplastic resin is selected from polyamide, acrylic resin, polyolefin, polyester, polycarbonate, acrylonitrile butadiene styrene, methyl methacrylate butadiene styrene, polylactic acid, polyphenylene sulfide, polyetheretherketone, polymethyl methacrylate and polyoxymethylene, and polyurethane.

[0021] 9. The article according to any one of the foregoing embodiments, characterized in that the thermoplastic resin is methyl methacrylate, acrylonitrile, butadiene, and styrene.

[0022] 10. The article according to any one of the foregoing embodiments, characterized in that the thermoplastic resin is present in a weight percentage of 15-20% relative to the molding material.

[0023] 11. The article according to any one of the foregoing embodiments, characterized in that the coupling agent is an ethylene-methacrylic acid copolymer.

[0024] 12. The article according to embodiment 10, characterized in that methacrylic acid is present in the copolymer at a weight percentage of 5-20%.

[0025] 13. The article according to any one of the foregoing embodiments, characterized in that the reinforcing material is formed of glass fiber, glass beads, carbon fiber and / or aramid fiber.

[0026] 14. The article according to any one of the foregoing embodiments, characterized in that the reinforcing material is present in a weight percentage of 1-6%.

[0027] 15. The article according to any one of the foregoing embodiments, characterized in that the pigment is organic.

[0028] 16. The article according to embodiment 15, characterized in that the pigment is fluorescent and / or phosphorescent.

[0029] 17. The article according to any one of the foregoing embodiments, characterized in that the article is an external component of a watch, selected from the watch case frame, watch case back cover, bezel, push rod, watch bracelet links, hands, and dial.

[0030] 18. A method for manufacturing decorative articles, comprising the following sequential steps: a) Preparation of granules, which include -60-90% metallic or ceramic material, wherein the metallic or ceramic material has a density greater than or equal to 5 g / cm³. -9-25% thermoplastic resin, -1-7% coupling agent, -0-8% reinforcing material, -0-3% pigment, b) Injection molding the granules to form the decorative article.

[0031] 19. The method according to embodiment 16, wherein the thermoplastic resin is methyl methacrylate, acrylonitrile, butadiene, and styrene.

[0032] 20. The method according to embodiment 17, wherein the methyl methacrylate acrylonitrile butadiene styrene is in powder form and has a d90 of less than or equal to 500 μm, preferably less than or equal to 315 μm.

[0033] 21. The method according to embodiment 17 or 18, characterized in that the weight percentage of methacrylate acrylonitrile butadiene styrene is 15-25 wt%, preferably 15-20 wt%.

[0034] 22. The method according to any one of embodiments 16 to 19, characterized in that the coupling agent is an ethylene-methacrylic acid copolymer in powder form having a d90 of less than or equal to 500 μm, preferably less than or equal to 315 μm.

[0035] 23. The method according to any one of embodiments 16 to 20, characterized in that the metal or ceramic powder has a d90 of less than or equal to 100 μm, preferably less than or equal to 30 μm, and more preferably less than or equal to 16 μm.

[0036] 24. The method according to any one of embodiments 16 to 21, characterized in that the reinforcing material is in the form of fibers with a length of less than or equal to 300 μm, preferably less than or equal to 200 μm.

[0037] 25. The method according to embodiment 16, characterized in that step a) by extrusion comprises: firstly introducing the metal or ceramic material and coupling agent powder into the extruder hopper, and secondly introducing the thermoplastic resin and the reinforcing material into another side hopper of the extruder so as to coat the metal or ceramic material with the coupling agent before introducing the thermoplastic resin and the reinforcing material.

[0038] 26. The method according to embodiment 23, wherein the pigment is introduced into another side hopper or is introduced during the injection molding process. Attached Figure Description

[0039] Figure 1 This refers to a timepiece comprising a case frame made of a heavy composite material according to the invention. Detailed Implementation

[0040] This invention relates to decorative articles made of composite materials including plastic and metal or ceramic materials. These decorative articles can be components of watches, jewelry, bracelets, etc. In the field of watchmaking, the article can be an external part, such as a watch case frame, case back, bezel, pusher, bracelet links, hands, dial markings, etc. By description, in... Figure 1 The image shows the inner frame 1 of the watch case made of a composite material according to the invention.

[0041] This decorative item is made by injection molding. The manufacturing method includes the following steps: a) Prepare granules of a few millimeters in size, which, by weight, comprise: -60-90% metallic or ceramic material, wherein the metallic or ceramic material has a density greater than or equal to 5 g / cm³. -9-25% thermoplastic resin or a mixture of thermoplastic resins, -1-7% coupling agent, -0-8% reinforcing material, preferably 1-6%, -0-3% pigment, b) The granules are injection molded to form the decorative article. The injection molding process is carried out in a mold at a temperature of about 90-100°C, and during the injection process, the temperature of the material is 200-300°C, preferably 220-280°C.

[0042] In step a), granules can be prepared by slicing the raw materials from the extrusion rolls. Advantageously, before introducing the thermoplastic resin and reinforcing material, the metal or ceramic material, both in powder form, and the coupling agent are first introduced into the hopper of the extruder to coat the metal or ceramic powder with the coupling agent. Thus, in the second stage, the thermoplastic resin and reinforcing material are introduced, for example, laterally into another hopper of the extruder. Pigments can be introduced during the extrusion process, and advantageously in the second stage. Pigments can also be mixed with the granules only before injection molding.

[0043] The metal powder can be, for example, conventional carbon steel powder, stainless steel powder, copper powder, copper alloy powder, or tungsten powder. Noble metal powder or noble metal alloy powder—typically gold, silver, or platinum—is also conceivable. Preferably, it is nickel-free stainless steel powder. The steel powder is preferably present at 60-80% by weight. The tungsten powder is preferably present at 65-90% by weight. Ceramic powder, such as ZrO2, CeO2, ZnO powder, etc., can also be used. Some ceramic powders have the advantage of being white, which is beneficial for pigment staining compared to metal powders. Advantageously, the metal or ceramic powder is present at 71-80% by weight. The grain size of the powder is such that d90 is less than or equal to 100 μm, preferably less than or equal to 30 μm, more preferably less than or equal to 16 μm.

[0044] The thermoplastic resin can be polyamide, acrylic resin, polyolefin, polyester, polycarbonate, acrylonitrile butadiene styrene, methyl methacrylate butadiene styrene, polylactic acid, polyphenylene sulfide, polyetheretherketone, polymethyl methacrylate, polyoxymethylene, terephthalate (PBT), and thermoplastic elastomer resin, or mixtures thereof. Preferably, it is methyl methacrylate acrylonitrile butadiene styrene (MABS), which is a transparent ABS. Preferably, the thermoplastic resin is introduced in powder form to facilitate the mixing process during granule preparation. In the case where commercially available MABS is in granule form with a diameter of a few millimeters, the steps prior to step a) include micronizing the granules to obtain a powder with a d90 less than or equal to 500 μm and preferably less than or equal to 315 μm.

[0045] Coupling agents are essential to ensure proper adhesion between metal or ceramic powders and thermoplastic resins. Advantageously, it is an ethylene-methacrylic acid copolymer, wherein the weight percentage of methacrylic acid in the copolymer is 5-20%. Advantageously, this copolymer is combined with MABS as a thermoplastic resin. The coupling agent can be introduced in powder form, the powder having a d90 of less than or equal to 500 μm, preferably less than or equal to 315 μm.

[0046] This reinforcing material can exist in various forms, such as fibers or granules. For example, it can be glass fiber, glass beads, carbon fiber, and / or aramid fiber, with a fiber length of less than or equal to 300 μm, preferably less than or equal to 200 μm. Its purpose is to improve the toughness of the material and / or limit its shrinkage during injection molding.

[0047] The pigment is preferably an organic pigment, which has a greater ability to stain metal or ceramic powders than inorganic pigments. For example, it can be carbon black for black, diketopyrrolopyrrole for red (e.g., Irgazin Red K3840LW from BASF), copper phthalocyanine for blue (e.g., Heliogen Blue K7096 from BASF), and monoazo pigments for yellow (e.g., Paliotol Yellow K1760 from BASF), etc. According to a variant, the pigment can be fluorescent and / or phosphorescent.

[0048] Articles obtained in this way include metallic or ceramic materials and plastic (or synthetic) materials containing thermoplastic resins, coupling agents, and any byproducts produced by the reaction between the resin and the coupling agent during extrusion or injection molding processes. It also includes reinforcing materials and pigments, if the latter are present.

[0049] As an example, cylindrical granules with a diameter and length of approximately 3 mm were tested for injection molding to produce a watch case frame. The granules comprised a homogeneous mixture by weight of 72% Carpenter nickel-free stainless steel powder (Fe17Cr11Mn3Mo) with a d90 < 16 μm, 18.5% micronized MABS (Terlux 2802) with a d90 < 315 μm, 3.5% ethylene methacrylate (Coathylene RP 9065-34) containing 15% acid, and 6% 200 μm long glass fibers (Glasfaser-Flocken from Suter-Kunststoffe AG). Another mixture was prepared with the same percentages of MABS and coupling agent, but containing 71% stainless steel and 1% carbon black (Printex 55 black).

[0050] The case frame exhibits a good aesthetic finish, appearing gray for the unpigmented composition and black for the pigmented composition. The resulting case frame has a density of 3.05 g / cm³ for the gray version and 3 g / cm³ for the black version. Charpy impact tests followed by water resistance tests on the integrated case frame also demonstrate the high toughness of the case frame made from the aforementioned composition.

Claims

1. A decorative article made of a molding material with a density of 2-7 g / cm³, wherein the molding material comprises, by weight: -60-90% metallic or ceramic material, wherein the metallic or ceramic material has a density greater than or equal to 5 g / cm³. -9-25% thermoplastic resin, -1-7% coupling agent, -0-8% reinforcing material, -0-3% pigment, The thermoplastic resin mentioned above is methyl methacrylate, acrylonitrile, butadiene, and styrene. The coupling agent is an ethylene-methacrylic acid copolymer.

2. The article of claim 1, wherein The metal material is conventional carbon steel, stainless steel, tungsten, copper, or copper alloy.

3. The article of claim 1 or 2, wherein, The metal material is stainless steel, which is present in the molding material at a weight percentage of 60-80%.

4. The article of claim 1 or 2, wherein, The metallic material is tungsten, which is present in the molding material at a weight percentage of 65-90%.

5. The article of claim 1, wherein The ceramic material is zinc oxide, zirconium oxide, or cerium oxide.

6. The article of claim 1, wherein The metallic material is a precious metal or a precious metal alloy.

7. The article of claim 1 or 2, wherein The metal or ceramic material is present in 71-80% by weight.

8. The article of claim 1 or 2, wherein, The thermoplastic resin is present in a weight percentage of 15-20% relative to the molding material.

9. The article according to claim 1, characterized in that, Methacrylic acid is present in the copolymer at a weight percentage of 5-20%.

10. The article according to claim 1 or 2, characterized in that, The reinforcing material is formed from glass fiber, glass beads, carbon fiber and / or aramid fiber.

11. The article according to claim 1 or 2, characterized in that, The reinforcing material is present at a weight percentage of 1-6%.

12. The article according to claim 1 or 2, characterized in that, The pigment is organic.

13. The article of claim 12, characterized in that, The pigment is fluorescent and / or phosphorescent.

14. The article according to claim 1 or 2, characterized in that, The item is an external component of a watch, selected from the watch case frame, watch case back, bezel, push rod, watch bracelet links, hands, and dial.

15. A method for manufacturing decorative articles, comprising the following sequential steps: a) Preparation of granules, which include -60-90% metallic or ceramic material, wherein the metallic or ceramic material has a density greater than or equal to 5 g / cm³. -9-25% thermoplastic resin, -1-7% coupling agent, -0-8% reinforcing material, -0-3% pigment, b) Injection molding the granules to form the decorative article. The thermoplastic resin mentioned above is methyl methacrylate, acrylonitrile, butadiene, and styrene. The coupling agent is an ethylene-methacrylic acid copolymer.

16. The method according to claim 15, characterized in that, The methyl methacrylate acrylonitrile butadiene styrene is in powder form and has a d90 of less than or equal to 500 μm, preferably less than or equal to 315 μm.

17. The method according to claim 15 or 16, characterized in that, The weight percentage of methacrylate, acrylonitrile, butadiene, and styrene is 15-25 wt%, preferably 15-20 wt%.

18. The method according to claim 15 or 16, characterized in that, The coupling agent is an ethylene-methacrylic acid copolymer in powder form, having a d90 of less than or equal to 500 μm, preferably less than or equal to 315 μm.

19. The method according to claim 15 or 16, characterized in that, The metal or ceramic powder has a d90 of less than or equal to 100 μm, preferably less than or equal to 30 μm, and more preferably less than or equal to 16 μm.

20. The method according to claim 15 or 16, characterized in that, The reinforcing material is in the form of fibers with a length of less than or equal to 300 μm, preferably less than or equal to 200 μm.

21. The method according to claim 15, characterized in that, Step a) performed by extrusion includes: firstly introducing a metal or ceramic material and a coupling agent powder into an extruder hopper, and secondly introducing the thermoplastic resin and the reinforcing material into another side hopper of the extruder so as to coat the metal or ceramic material with the coupling agent before introducing the thermoplastic resin and the reinforcing material.

22. The method according to claim 21, characterized in that, The pigment is introduced into another side hopper or during the injection molding process.

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