WO2017005285A1

WO2017005285A1 - Antique gold plated gemstone setting

Info

Publication number: WO2017005285A1
Application number: PCT/EP2015/065271
Authority: WO
Inventors: Martin Rauch; Christoph TRIENDL
Original assignee: D. Swarovski Kg
Priority date: 2015-07-05
Filing date: 2015-07-05
Publication date: 2017-01-12

Abstract

The invention relates to a method for producing an artificial antique gold layer on a gemstone setting. The antique gold layer is characterized by an appearance that corresponds to a natural aging progression. The invention also relates to products produced by the method.

Description

Gemstone setting with antique gold coating

Field of the invention

The invention relates to a method for producing an artificial "antique gold coating" on a blank of a gemstone socket, as well as the products which are produced by this method.

State of the art

For the design of gemstone settings, it is often desirable that the metallic parts assume a characteristic appearance created by weathering and aging. In particular, gold receives a characteristic partially matt, darker appearance due to weathering and aging. The natural aging process takes much too long for the production of jewelry. Therefore, it is desirable to artificially produce this effect. In jewelery production, a jewelery base is often made of a low-cost material, for example brass, a copper-zinc alloy or pure zinc. These materials are easy to coat. The gemstone bezel is gold plated and is not entirely gold because the gold coating is more cost effective. By wearing on the skin, as is usually the case with jewelery, the desired "Vi ntage effect", as a result of the reaction with sweat skin after a short time would be very unsightly Therefore, it is desirable to develop a metal-containing layer sequence, which especially in the jewelry sector the decorative claims of a "Vi ntage- effect" and the wearing requirements, especially a protection against sweat, is sufficient. From US 7,018,677 B2 and US 8,007,866 B2, the artificial production of an aging effect of copper is already known. The artificial production of the natural aging effect of gold is not described. In US 8,956,510 B2 the coating of jewelry is described. Although the manufacture of coatings is well known for jewelry, it does not cite the generation of a natural aging effect of gold. US 2009/0139264 A1 describes the production of an antique gold effect for jewelery. Signs are engraved on the jewelry surface and the jewelry weathers only during use. Object of the present invention is to realize an artificial "antique gold coating" on a gemstone setting, which is also friendly to the skin, does not react with sweat, has good adhesion and protects against mechanical erosion, such as scratches.

Description of the invention

Surprisingly, it has been found that the natural "Vi ntage effect" of the gold by an "antique gold coating" can be artificially produced by the inventive method and the "antique gold coating" of the gemstone version by the use of a protective varnish not Sweat reacts and is protected from mechanical erosion, for example scratches, which is of great importance for jewelery because the coating of the gemstones by the coating meets the wearing requirements The subject of the present application is therefore a process for coating a gemstone setting with gold, characterized by the following Steps: a) applying at least one metal layer to the gemstone socket,

b) partial application of a mask to the gemstone setting,

c) applying a copper layer to the masked gemstone socket,

d) aftertreatment of the gemstone socket with an oxidizing agent,

e) removal of the mask from the gemstone setting,

f) applying a protective varnish. Step a):

In general, there are many processes for coating metal parts, for example electroless processes in solution or electrolytic processes, or also processes such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). In this case, a thin metal layer is deposited on the surface of a material to be coated. All of these methods are suitable in principle according to the invention.

The electrolytic processes are electrochemical depositions of metal layers on surfaces to be coated. For this type of coating are conductive materials, such as conductive metals, conductive metal alloys or conductive plastics. In the electrolytic processes, the material to be coated is immersed in a solution of the coating material. By applying an external current, the coating material deposits on the material to be coated. Electroless coating processes in solution, such as reductive, occur without the use of an external power source. Such a metal deposition with the addition of reducing agents to the electrolyte is based on the oxidation of the reducing agent with release of electrons, which lead to a reduction of the metal ions.

The inventive method allows for jewelry in terms of aesthetics and design very many design options. The "anti-gold coating" can be applied in principle to any electrically conductive material, for example brass or electrically conductive plastics According to the invention, jewelery in which the gemstone mount is made of brass or a brass-containing alloy, since brass is made Brass is well coated and mechanically well machined Brass and all other metals and alloys mentioned herein are used in the purity known to those skilled In the art, if a gemstone socket is to be copper plated, it is advantageous to use a cyanide copper electrolyte first The resulting, mostly thin layer of copper is then reinforced with an acidic copper electrolyte.The pre-coppering is necessary because it is not possible due to the low pH of an acidic copper electrolyte t directly coat zinc die castings. The zinc would dissolve. In contrast, brass jewel casings can be directly coated with an acidic copper electrolyte.

In the method according to the invention, at least one metal layer is deposited electrolytically on the gemstone casing. Preferably, a copper layer is deposited on the gemstone socket, since copper is cheaper than gold and better adheres to brass. When coppering the metal parts, preferably a copper layer thickness of 1 to 10 μιτι is applied, in particular 5 to 10 μιτι and particularly preferably from 7 to 9 μιτι.

On the copper layer, a palladium layer is preferably deposited. Palladium forms a barrier layer that prevents the diffusion of copper into the subsequently deposited gold layer. Various processes are known to the person skilled in the art for the deposition of the palladium-containing layer, and the deposition of this layer is preferably carried out by electrolysis. Electrolytically, a palladium layer of 0.1 to 10 μm is preferably applied, in particular 0.1 to 5 μm, and particularly preferably 0.2 to 0.3 μm. For the purposes of the invention, it is also conceivable that palladium is deposited together with at least one other metal, wherein the content of palladium based on the weight of the deposited layer at least 50 wt .-%, preferably at least 60 wt .-% and more preferably at least 70 wt .-% is.

The gold layer is preferably deposited on the palladium layer according to the invention. The processes for the gold separation are well known to the person skilled in the art; Gold separation by electrolysis. Electrolytically, a gold layer of 0.1 to 10 μm is preferably applied, in particular 0.1 to 5 μm and particularly preferably 0.3 to 0.4 μm. For the purposes of the invention, it is also conceivable that gold is deposited in various degrees of purity. In order to obtain the characteristic appearance of the gold, a minimum gold content of the layer of 58.5% by weight is advantageous; a minimum gold content of 75% by weight is more advantageous according to the invention.

The layer sequence preferably contains a combination of copper with a layer thickness of 7 to 9 μιτι, palladium with a layer thickness of 0.2 to 0.3 μιτι and gold with a layer thickness of 0.3 to 0.4 μιτι.

Step b):

A partial masking is applied to the gilt gemstone setting. The masking serves to leave areas of the gold surface free in order to process them for the desired aging effect. If the masked gemstone socket is subsequently electrolytically coated again, the masking must not be electrically conductive. According to the invention, a stripping lacquer is preferably used for the masking. Peel-off coatings have the advantage that they can be applied to the material like a protective skin and then removed again without residue. Particularly preferred for the masking PVC Abziehlacke be used. Peel-off properties, such as adhesiveness, can be altered by monomeric and polymeric plasticizers. To apply the Abziehlackes there are a variety of ways, for example, there is the possibility of spraying or liquid application. The methods are well known to those skilled in the art. However, it is also possible to use other lacquers or general materials as masks, which can be applied as a mask and removed without leaving any residue, and which can be used in the subsequent electrolysis. The masking is preferably applied according to the invention with a stencil. The template can be made of a variety of materials, such as plastic, metal or textile. The template releases those areas that are to be further processed, the others remain covered.

Step c):

In step c) of the method, a copper layer is deposited on the masked gemstone mount according to the invention. The deposition is preferably carried out electrolytically. By masking the copper is deposited only at the left of the masking bodies.

Step d):

In process step d), the copper-plated and masked gemstone casing is treated with an oxidizing agent. Potassium permanganate is preferably used as the oxidizing agent. For the treatment with the potassium permanganate, the Schmucksteinfasssung is immersed, for example, in an aqueous potassium permanganate solution or sprayed with an aqueous potassium permanganate solution. The uncovered coppered areas react with the oxidizing agent and are thereby discolored brownish.

Steps):

Subsequently, the masking is removed with a solvent, for example ethyl acetate. Step f):

In process step f), a protective lacquer is applied to the gemstone casing. The protective varnish prevents the metal parts from reacting with the sweat of the skin and also improves the resistance of the metal layers. According to the invention, varnish is understood as meaning a liquid or pulverulent coating material which is applied thinly to objects and is built up by chemical or physical processes, for example evaporation of the solvent, to form a continuous, solid layer. Paints often contain binders, fillers, pigments, solvents, resins and / or acrylates and additives, such as biocides. Suitable examples are acrylic lacquers, epoxy lacquers or polyurethane lacquers.

Acrylic paints are manufactured on the basis of acrylic resins. Acrylic resins are synthetic resins and are considered particularly durable. Acrylic resins are based on polymers or copolymers of acrylic acid or methacrylic acid and their esters. They are often copolymerized with other unsaturated monomers, such as styrene or acrylonitrile. Acrylic paints are either dissolved in solvents or dispersed in water and applied to the coated gemstone mount. Acrylic coatings have a high weather resistance and are UV-resistant and are therefore particularly well suited according to the invention.

Epoxy paints often contain the two components epoxy resin and hardener. Epoxy resins are polyadducts of epichlorohydrin with bisphenol derivatives, for example A, F or S. These are crosslinked with a hardener. Usually, the two components epoxy resin and hardener are mixed shortly before processing. Epoxy coatings are characterized by high chemical and mechanical resistance, but are not optimal in terms of UV resistance. For polyurethane coatings, the urethane group is characteristic. They are commercially available as one-component and multicomponent coatings, for example the hardener is already mixed with the base coat in the case of one-component lacquer and the hardener and base coat are separated in the two-component lacquer. Polyurethane coatings are particularly hard, abrasion resistant and resistant to water, oils and chemicals. According to the invention, a polyurethane varnish is preferably used as the protective varnish. Polyurethane paints have good adhesion properties and are resistant. Two-component polyurethane acrylic resin paints have proven to be advantageous, in particular the products DE 4259x from Hesse and Lignal, since they are saliva and sweat resistant according to DIN 53160. They can be applied without thermal aftertreatment and are lightfast.

Optionally, the gemstone socket can be cleaned or degreased before applying the metal layer. Degreasing is the removal of adhering fats, oils or other contaminants with degreasing agents. The cleaning or degreasing of, for example, brass has the advantage that the adhesion of the metal layer a) is improved.

The cleaning can be done mechanically, for example by grinding and polishing, with solvents, for example ethyl acetate, or else with ultrasound, for example with the Evolution WP-K device from German Sonic. Another option for pretreatment is electrolytic degreasing. During the electrolytic degreasing, the gemstone socket is in a solution and is then cleaned by applying a current. In electrolytic degreasing, a distinction is made between cathodic and anodic degreasing. The cathodic degreasing proceeds under hydrogen evolution and the anodic degreasing under evolution of oxygen. The cathodic degreasing is preferably used because it can be achieved with brass, for example, a very good cleaning. For degreasing of brass parts is especially the cathodic, alkaline electrolytic degreasing.

To further improve the adhesion of the metal layer a), prior to applying the metal layer a) to, for example, brass, the brass surface may optionally be treated with acid to remove oxide layers. Sulfuric acid has proven to be advantageous for the cleaning of brass jewel casings.

To enhance the Vi ntage- effect, the surface of the gemstone mount from example brass can be optionally roughened before applying the metal layer a). The gemstone socket thus receives a surface that corresponds to a surface caused by weathering and aging. The brass is preferably dipped in nitric acid.

The optional cleaning or degreasing and the optional roughening of the surface of the gemstone setting can be done in any order.

Another object of the application are products which are obtainable by the process according to the invention. The preferred embodiments of the process lead to inventively preferred products. Preference is given according to the invention to gemstone casings, comprising the following layer sequence: a) copper,

b) palladium,

c) gold,

d) partial copper layer areas on the gold layer and a

e) protective lacquer.

General process description The gemstone socket is optionally cleaned or degreased. For degreasing of brass parts is especially the cathodic, alkaline electrolytic degreasing. In this degreasing, the solution contains, for example, caustic soda and surfactants. The degreasing is carried out for a period of at least 1 minute, a temperature of 35Ό - 55Ό and a current density of at least 3 A / dm ^2, for example with the 1018 agent IWG-Plating Vienna.

In order to remove oxide layers from the brass surface, treatment of the gemstone casing with 5-15% sulfuric acid (% by weight) has proven to be advantageous. The gemstone socket is immersed in the sulfuric acid according to the invention for about 1 minute. Thereafter, the gemstone socket is cleaned with deionized water.

To optionally roughen the surface of the brass gemstone casing, the brass is immersed in nitric acid (about 55 to 65% by weight) for at least 20 seconds.

After the optional pretreatment of the metallic gemstone socket, the gemstone socket is electrolytically coated with copper in step a) of the method. The electrolyte used can be, for example, Cupracid® 210 from Atotech. When coppering the metal parts, a layer thickness of 7 to 9 μιτι is particularly preferably applied. On the copper layer, a palladium layer is electrolytically applied particularly preferably with a layer thickness of 0.2 to 0.3 μιτι. For example, the product Gapal TS from IWG can be used for the palladium coating. On the palladium layer, the gold layer is preferably applied electrolytically with a layer thickness of 0.3-0.4 μιτι. For the gold coating, for example, the product MC 210 from IWG is suitable.

In method step b), a masking is partially applied to the gold-plated gemstone socket. There are various possibilities for this, for example by spraying or by liquid application, in that according to the invention a stencil is preferably used. For masking, for example, peelable coatings, for example Redowax 1 12 from Erne or Galvanolack GC 1 10 from Adhesive Products, are suitable on account of their adhesion properties. Thereafter, the gem stone version is dried. In step c) of the process, the gold-plated and masked gemstone casing is electrolytically coated with copper (about 2 to 3 μιτι). The copper is deposited on the vacant areas of the mask. In process step d), the copper-plated gemstone casing is aftertreated with an oxidizing agent by immersing it in a potassium permanganate solution (about 10 to 15% by weight) at a solution temperature of about 70 ° to 90 ° for at least 20 seconds. The copper layer is discolored by the reaction with the oxidizing agent. The masking has gold-plated areas and areas of oxidized copper.

In step e) of the process, the masking is removed with a solvent, for example ethyl acetate.

In process step f), a protective lacquer is applied to the gemstone casing in order, for example, to prevent the reaction of skin sweat with the gemstone casing. As a protective varnish, acrylic varnish, epoxy varnish, for example Duralit® 1516-754 S from Rohm and Haas or also polyurethane varnish can be used. A two-component polyurethane-acrylic resin paint, for example DE 42597-0040 from Hesse & Lignal, has proved to be advantageous.

Inventive example (FIG. 1)

On a brass gemstone mount in the following manner, an "antique gold coating" was applied.

The gemstone frame made of the FRMSBR alloy from AGS Alpha Guss Metals and Alloys GmbH Pforzheim was degreased electrolytically with the agent 1018 from IWG-Plating Wien for 5 minutes at a temperature of 45 ° and a current density of 5 A / dm ² . Thereafter, the degreased brass parts were washed with deionized water.

For removal of oxide layers, the brass jewelry frame was immersed for about 1 minute in a 10% sulfuric acid (wt .-%). Thereafter, the gemstone socket was washed again with deionized water.

Subsequently, the gemstone socket was immersed in nitric acid (60% by weight) for about 30 seconds.

Subsequently, the brass jewel case was dipped wet in a copper bath and coated in the copper bath Cupracid® 210 from Atotech at 25Ό, a current density of 1, 5 A / dm ² and a duration of 8 minutes with a copper layer.

On the copper layer, a palladium coating was applied electrolytically with Gapal TS from IWG at 25, a current density of 1 A / dm ² and a duration of 2 minutes.

On the palladium coating, a gold coating was applied electrolytically with MC 210 from IWG at 45 °, a current density of 1 A / dm ² and a duration of 2 minutes.

The masking with the Redowax 1 12 stripping paint from Erne was partially applied to the gold-plated gemstone setting using a stencil.

The gemstone socket was dried and then coated in the bright copper bath Cupracid® 210 from Atotech at 25, a current density of 1, 5 A / dm ² and a duration of 2 minutes with a copper layer.

Subsequently, the copper-plated gemstone socket was thawed for approximately 30 seconds in a 10% potassium permanganate solution (wt%) with about 8CC.

The stripping lacquer was removed with the solvent ethyl acetate. The gemstone socket was coated with the protective coating by being dipped in the two-component polyurethane-acrylic resin paint DE 42597-0040 from Hesse & Lignal and dried at about 25 ° C. for a period of about 14 hours.

Claims

Claims Gemstone setting with antique gold coating.

1 . A process for coating a gemstone socket with gold, characterized by the following steps: a) application of at least one metal layer to the gemstone socket, b) partial application of a masking to the gemstone socket,

c) applying a copper layer to the masked gemstone socket, d) aftertreating the gemstone socket with an oxidizing agent, e) removing the masking from the gemstone socket,

f) applying a protective varnish.

2. The method according to claim 1, characterized in that the gemstone mount is made of brass or a brass-containing alloy.

3. The method according to at least one of the preceding claims, characterized in that the metal layer is electrodeposited in step a).

4. The method according to at least one of the preceding claims, characterized in that the metal layer in step a) contains copper or consists of copper.

5. The method according to claim 4, characterized in that on the copper layer in step c) a palladium layer is deposited.

6. The method according to claim 5, characterized in that a gold layer is deposited on the palladium layer.

7. The method according to at least one of the preceding claims, characterized in that for the masking in step b) a Abziehlack is used.

8. The method according to at least one of the preceding claims, characterized in that the masking in step b) is applied with a template.

9. The method according to at least one of the preceding claims, characterized in that for the post-treatment in step d) potassium permanganate as

Oxidizing agent is used.

Process according to at least one of the preceding claims, characterized in that a polyurethane varnish is used as the protective varnish in step f).

Gemstone socket obtainable by a method according to at least one of the preceding claims.

Gemstone socket according to claim 1 1, comprising a layer sequence

a) copper,

b) palladium,

c) gold,

d) partial copper layer areas on the gold layer and a

e) protective lacquer.