WO2022111999A1

WO2022111999A1 - Galvanically decorated component

Info

Publication number: WO2022111999A1
Application number: PCT/EP2021/081222
Authority: WO
Inventors: Dirk Kieslich
Original assignee: Gerhardi Kunststofftechnik Gmbh
Priority date: 2020-11-30
Filing date: 2021-11-10
Publication date: 2022-06-02
Also published as: DE202020106865U1

Abstract

The invention relates to a galvanically decorated component which is produced from a galvanizable plastic in an injection molding method and has a front side (1) and a rear side (2). A recessed geometry (7) is introduced into the component, which has a peripherally closed contour.

Description

Electroplated component

The invention relates to a galvanically decorated component which is produced from a plastic which can be electroplated using an injection molding process and which has a front side and a rear side.

In the automotive industry, various and differently decorated plastic components are used for visual enhancement. Conventional surface technologies of such surface-decorated components are the manufacture of undecorated plastic surfaces by injection molding, painting of the plastic surfaces, graining and etching of the tool surfaces to be reproduced and molding of these by plastic injection molding, electroplating of the plastic surface, decoration in the injection mold by IMD (in mold decoration), A print printed on a carrier film is molded from a carrier film in the injection molding process, the back-injection of printed and partially deformed and contour-following punched film inserts using FIM technology (Film Insert Molding) and metal foil back-injection. In addition to all these classic surface technologies, the representation of metallic surfaces on plastic components is currently very popular, as this surface suggests a high-quality and robust appearance like no other. In addition to the components decorated with real metal, i.e. veneered, joined or back-injected components with thin stainless steel or aluminum sheets, metal-coated plastic components are also particularly preferably used as decorative elements. A type of coating with which it is possible to achieve optically metallic surfaces is, for example, gas phase deposition, which includes the PVD process (physical vapor deposition) and its modified technologies, with for example CVD (Chemical Vapor Deposition) and PeCVD (Plasma-enhanced Chemical Vapor Deposition) and others. Thin metal layers are deposited on a plastic component in an evacuated vacuum chamber. The material to be deposited is in solid form. The evaporated material moves through the coating chamber and hits the component to be coated, where it forms a layer as a result of precipitation. The PVD process is generally suitable for producing metallic layers; however, it has proven to be problematic that the very thin metal coating does not have sufficient resistance to abrasion and corrosion without an additional protective layer. For this reason it is necessary to have a

To apply protective layer, such as a clear coat system. In order to achieve sufficient basic adhesion to the plastic component to be deposited, it is usually also necessary to paint an adhesion promoter. Recently, a surface with a chrome appearance can also be created by applying a coating from special coating systems.

However, the most widespread and industrially established method is the galvanic deposition of metals on plastic components. The components are first produced in an injection molding process, for example from butadiene-containing copolymers, for example from ABS or ABS/PC. After the injection molding process, the components are chemically pre-treated in order to then autocalalytically deposit a first thin metal layer on them, usually a thin layer of nickel or copper. In the further electroplating process, further metal layers are then deposited electrolytically until the electroplating process is usually completed with a deposited chrome layer.

Due to the galvanic, i.e. electrochemical deposition in electrolytes, in contrast to a surface decoration with foils or metal foils, by painting or in contrast to the PVD coating, the back of the component is always coated at the same time. Especially with regard to the desired conservation of resources, this undesired co-coating of the rear side of the component usually represents a disadvantage. Also in relation to mechanical ones Connections of the components to other components of the vehicle, for example by clipping, and for attachment, for example by welding, this galvanic deposition is usually disadvantageous. If additional light applications are desired, the otherwise galvanized, metallized rear side of the component needs to be treated. In the case of small quantities or sample parts, the deposited chrome layer can be removed mechanically after the electroplating process. For large series, however, this post-treatment is usually too expensive.

Another way to keep the back of the component free of chrome or metal is to use an overmolded film made of a galvano-inert material, such as polycarbonate. The film is usually deformed according to the geometry of the component, punched and then inserted into the cavity of the injection mold as a film insert. The film is compatible with the electroplating material used, made of ABS or ABS/PC.

Another option is to paint the back of the component with a galvano-inert paint system. Here either a ring can be placed around the areas to be transilluminated later or the entire rear side of the component is painted over the entire surface.

Each of the measures mentioned is in itself suitable for avoiding a galvanic coating on the rear side of the component or for removing the coating again after the galvanic process; however, it always requires additional processing of the component and thus causes additional costs.

This is where the invention aims to remedy the situation. The invention is based on the object of creating a galvanically decorated component in which the rear side of the component is uncoated without additional processing being required for this purpose. According to the invention, this object is achieved with the features of claim 1. With the invention, a galvanically decorated component is created in which the rear side of the component is uncoated without additional processing being required for this. Due to the recessed geometry introduced into the component, electroplating of the area between the geometry is prevented. Due to the recessed geometry, there is no or only slight and ineffective pickling during the pre-treatment of the component, no or only slight and ineffective activation and no or only slight deposits that are insufficient for the subsequent electrolytic deposition processes of nickel and other metals. Therefore, there is no current-carrying layer at the bottom of the geometric structure, which is why the areas enclosed by the geometry remain free of chrome or metal in the further electroplating process.

Other developments and refinements of the invention are specified in the remaining dependent claims. An embodiment of the invention is shown in the drawings and will be described in detail below. Show it:

FIG. 1 shows the schematic representation of a galvanically decorated component according to the invention in cross section;

FIG. 2 shows the plan view of the rear side of the galvanically decorated component according to FIG.

The component selected as an exemplary embodiment is preferably intended for use in automobile construction. It is made from just one plastic using the injection molding process (so-called 1K component). The plastic can be any plastic that can be electroplated, preferably ABS (acrylonitrile butadiene styrene copolymer) or ABS-PC. The component has a front side 1, which usually forms the viewing side of the component after it has been installed in the vehicle. The component also has a back 2 . The component is solid. But it can also be provided between the front 1 and back 2 with a cavity for Increase the stability can be provided with ribs. Side walls 4 are formed on the component, which connect the front side 1 and the back side 2 to one another. On the back 2, the component is provided with at least one fastening element 5, which enables the component to be stably attached to other components of the vehicle. This can be tabs with which clipping is possible. But it can also be a matter of welding lugs, with which the component can be welded to other plastic components.

On the back 2, the component is also provided with at least one electroplating tab 6, which is used for electrical contacting during the electroplating process. Due to the electrical contact that forms the cathode, the metal located on the anode and to be applied to the component can be deposited on the component during the electrolytic bath.

On the back 2, a recessed geometry 7 is introduced into the component, which is designed in the manner of a groove. It has an all-round closed contour. It is a closed route. This one can

be (circular) ring-shaped. The recessed geometry 7 can also be designed in the manner of a polygon, for example in the manner of a square, pentagon, etc. Other shapes are also possible. Due to the recessed geometry 7 designed as a circumferentially closed contour, an enclosed area 8 or an island is created, which is delimited by the recessed geometry 7 . The recessed geometry 7 has very small dimensions. The geometry 7 preferably has a depth of 0.2 to 0.75 mm, preferably 0.35 to 0.5 mm, and a width of 0.05 to 0.5 mm, preferably 0.1 to 0.2 mm. The component is provided with a galvanic layer 9 . As can be seen from FIG. 1, the electroplated layer 9 extends from the front side 1 via the side walls 4 to the geometry 7 on the back side 2 of the component. The design of the recessed geometry 7 according to the invention in the form of a closed stretch has the following effect: as is known, plastics are usually not electrically conductive. For this reason, the surface of the plastic component must first be coated with a well-adhering, electrically conductive layer for subsequent electrolytic coating. The first step in the electroplating of plastics is therefore the roughening of the surface. This is usually done by pickling, which is done with the help of a liquid medium, for example a pickling agent, acid or lye. Due to the very small dimensions of the deepened geometry 7, the media of the pretreatment do not succeed in squeezing out the air cushion located in the geometry 7 or in completely filling or flooding the geometry 7. As a result, due to the geometry 7, there is no pickling and no activation. The geometry 7 thus remains untreated, at least in its basics.

The same applies to the further electroplating process. Here, too, the metals do not succeed in squeezing the air cushion out of geometry 7. As a result, no metals get into the bottom of geometry 7. Should metals nevertheless penetrate to the bottom, they cannot adhere to geometry 7 because pickling has not taken place. As a result, geometry 7 lacks a current-carrying (metal) layer. The further consequence of this is that there is no deposition of nickel and the other metals in the areas 8 or islands enclosed by the geometry 7 . The islands or areas 8 are free of chrome or metal after the component has been electroplated.

With the invention, a component produced by plastic injection molding is created which, in the exemplary embodiment, is provided with a recessed geometry 7 with very small dimensions on the rear side 2 . In the geometry 7 designed in the manner of a groove, there is no chemical pre-treatment and subsequently no galvanically deposited metal coating due to its design. The geometry 7 thus interrupts a galvanic coating in those areas 8 of the component which are completely surrounded by the geometry 7 . The technique according to the invention can be used with all components in order to save resources, in particular metals. In this case, the geometry 7 can be created in a simple manner by the shaping injection mold, for example by means of a web in the mold. The web then forms the geometry or groove in the component. The further the geometry 7 is moved into the area of the side walls 4, the larger the uncoated area 8 created after electroplating. No metal layer is formed in this enclosed area 8.

Claims

patent claims

1. Galvanically decorated component, which is produced from a plastic that can be electroplated by injection molding and which has a front (1) and a rear (2), characterized in that a recessed geometry (7) is introduced into the component, which has a circumferentially closed has contour.

2. Component according to claim 1, characterized in that the recessed geometry (7) is introduced into the back (2) of the component.

3. Component according to claim 1 or 2, characterized in that the recessed geometry (7) is annular.

4. Component according to one of the preceding claims, characterized in that the recessed geometry (7) is designed in the manner of a polygon.

5. Component according to claim 4, characterized in that the recessed geometry (7) is designed in the manner of a square.

6. Component according to one of the preceding claims, characterized in that the recessed geometry (7) is designed in the manner of a groove.

7. Component according to one of the preceding claims, characterized in that the recessed geometry (7) has a depth of 0.2 to 0.75 mm, preferably 0.35 to 0.5 mm.

8. Component according to one of the preceding claims, characterized in that the recessed geometry (7) has a width of 0.05 to 0.5 mm, preferably 0.1 to 0.2 mm.