METHOD FOR PRODUCING AN EXTERIOR TRIM PART FOR A MOTOR VEHICLE

Description

[0001] The present invention relates to a method for manufacturing an exterior trim part for a motor vehicle, comprising the following steps: Providing a base body defining the outer cladding part, wherein the base body consists of a light-transparent or translucent plastic material and has a designated visible side and a rear side opposite the visible side, wherein a plurality of protrusions are provided which project from the surface of the visible side of the base body and which are formed integrally with the base body; applying an opaque layer of paint to the visible side of the base body and to the protrusions of the base body.

[0002] With methods or exterior cladding parts known from the prior art, it has not been possible so far to design a base body in such a way that selective illumination can only occur in the area of ​​the raised areas when a light source is arranged in the area of ​​the back.

[0003] A generic process can be found in document DE 10 2017 120 532 A1. A process for manufacturing a housing for electronic components is described in US 2009 / 237939 A1.

[0004] The invention therefore aims to provide a method for manufacturing an exterior trim part for a motor vehicle with the features described above, which makes it possible to modify the base body of the exterior trim part in such a way that the exterior trim part is visually appealing in the areas of the protrusions and at the same time partially translucent.

[0005] To solve this problem, the invention provides a method described below: A method for manufacturing an exterior trim part for a motor vehicle, comprising the following steps: providing a base body defining the exterior trim part, wherein the base body is made of a light-transparent or translucent plastic material and has a designated visible side and a rear side opposite the visible side, wherein a plurality of protrusions projecting from the surface of the visible side of the base body are provided, which are integrally formed with the base body; applying an opaque paint layer to the visible side of the base body and to the protrusions of the base body;wherein in a further step the paint layer on the raised areas is partially or completely removed, so that these areas of the raised areas are again translucent to light, and that subsequently at least on these areas a translucent decorative layer or decorative film is applied, so that the outer cladding part is partially translucent to light in these areas.

[0006] In this context, the term "light" refers not only to the part of the electromagnetic spectrum visible to the human eye, i.e., wavelengths between approximately 380 and 780 nm, but also to the near-infrared and infrared wavelength range from 780 nm to 1 mm.

[0007] Advantageously, the inventive method allows the production of an exterior trim part of a motor vehicle which is selectively translucent in the areas of the protrusions for the display of a functional light or a signal light (especially in darkness or at night) while simultaneously maintaining a color optic when the lighting behind the exterior trim part is deactivated or the ambient light (especially during the day) overpowers the partial illumination of the exterior trim part.

[0008] The paint layer can be multi-layered. In particular, the multi-layered paint layer can include a primer layer and at least one coloring layer. The decorative layer or decorative film can also be multi-layered.

[0009] The decorative layer is applied as an additional color layer using a pad printing process. A preferred pad printing process comprises the following steps: Pad printing is an indirect gravure printing process in which ink is transferred from a printing plate to the substrate (in this case, the raised areas) as an ink layer by an elastic pad made of, for example, silicone rubber. The transfer of the ink layer to the substrate is achieved by applying pressure with appropriate pressure. The ink to be transferred can be applied to a so-called cliché, which serves as the printing plate. The ink can be applied to the cliché using a squeegee, roller, or brush. The pad then rests on this cliché, lifts off, carrying ink with it, and moves to the substrate.The tampon then lowers into the support structure, adapting to its shape and leaving the dye on the support structure. These movements can be performed, for example, by a moving unit or a robot.

[0010] In the case of a decorative foil, it is applied using a hot stamping process. A preferred hot stamping process comprises the following features: a hot stamping process for transferring a transfer layer (decorative foil) of a hot stamping foil at a stamping temperature and pressure onto a substrate (in this case, the raised areas), wherein the transfer layer is arranged on a carrier film and a release layer is arranged between the transfer layer and the carrier film and / or an adhesive layer is arranged on the transfer layer, and wherein a stamping die is provided for transferring the transfer layer of the hot stamping foil onto the substrate. Both the pad printing process and the hot stamping process have proven particularly suitable in tests for applying the decorative layer or the decorative foil to the raised areas (where the ink layer has been partially or completely removed).Advantageously, choosing these two processes (hot stamping or pad printing) eliminates the need for masking of surrounding areas to prevent coating errors. This reduces production costs and improves manufacturing quality.

[0011] To partially or completely remove the paint layer from the raised areas in the next step, the paint layer can preferably be partially perforated or completely ablated using laser radiation. Reducing the thickness of the paint layer by removing only a portion of it is also conceivable. The use of a laser ablation or laser perforation process enables this step to be carried out with high precision and speed.

[0012] In addition to selecting a material that is inherently transparent or translucent (i.e., allows light to pass through), the decorative layer or film can preferably be made translucent due to its thickness. The decorative layer can include a further color layer, particularly one containing metallic particles or flakes. The decorative film can include at least one metal foil. Advantageously, both variants result in a metallic appearance of the decorative layer or film.

[0013] In a further step, a sealing, transparent or translucent clear coat and / or an additional protective layer can be applied over the paint layer and the decorative layer, or over the paint layer and the decorative film. This additional protective layer can, in particular, comprise a silane or a silane compound, or a polyurethane or a polyurethane compound, or a polyurea or a polyurea compound.

[0014] Preferably, the base body has a wall thickness in the range of 0.8 mm to 5.5 mm.

[0015] The exterior trim part to be manufactured may in particular be a bumper trim, a radiator trim, a tailgate trim, a pillar trim, a door trim, a fender trim, a roof trim, or a spoiler of a motor vehicle, or a component, assembly, or part of the aforementioned parts.

[0016] The basic body can be provided or manufactured using an additive manufacturing process (e.g. 3D printing), injection molding, or thermoforming.

[0017] The transparent or translucent plastic material of the base body can include, in particular, polycarbonate, polymethyl methacrylate, polystyrene (e.g., PS, ABS, ASA), thermoplastic polyester (e.g., PET, PBT), polypropylene, or a biopolymer (e.g., cellulose acetate, polyhydroxybutyrate, polylactic acid, polyhydroxyalkaline). A further process step can involve arranging a light-emitting element behind the back of the base body to emit light.

[0018] Part of the invention also includes an outer cladding part, manufactured according to the method described above. Examples of implementation

[0019] The invention will now be explained with reference to drawings illustrating only one embodiment. These schematically depict: Figures 1 to 5 are cross-sectional views that illustrate the process for manufacturing the outer cladding part.

[0020] In the figures, identical or functionally equivalent elements are given the same reference symbols.

[0021] The inventive method for manufacturing an exterior trim part 1 for a motor vehicle comprises the following steps: providing a base body 2 defining the exterior trim part 1, wherein the base body 2 consists of a light-transparent or translucent plastic material and has a suitable visible side A and a rear side B opposite the visible side A, wherein a plurality of projections 3 are provided which extend from the surface of the visible side A of the base body 2 and are formed integrally with the base body 2 (cf. Fig. 1 ).

[0022] Applying an opaque color layer 4 to the visible side A of the base body 2 and to the elevations 3 of the base body 2 (see figure). Fig. 2 ).

[0023] In a further step, the color layer 4 on the elevations 3 is partially or completely removed, so that these areas 5 of the elevations 3 can again be penetrated by light (cf. Fig. 3 ).

[0024] Subsequently, at least on these areas 5, a light-transmitting decorative layer 6 or decorative film 6 is applied, so that the outer cladding part 1 is partially translucent in these areas 5 (cf. Fig. 4 ).

[0025] The decorative layer 6 is applied using a pad printing process. If a decorative foil 6 is used, it is applied using a hot stamping process.

[0026] The color layer 4 is partially perforated or completely removed using laser radiation so that the areas 5 of the elevations 3 can be penetrated by light again.

[0027] The decorative layer comprises a further color layer, in particular a further color layer containing metallic particles or flakes. In the case of the use of a decorative foil 6, this may comprise at least one metal foil.

[0028] In a further step, a sealing, transparent or translucent clear coat 7 and / or an additional protective layer 7 is applied over the color layer 4 and the decorative layer 6, or over the color layer 6 and the decorative film 6. If a protective layer 7 or an additional protective layer 7 is applied, this protective layer 7 may, in particular, comprise a silane or a silane compound.

[0029] The base body 2 has a wall thickness ranging from 0.8 mm to 5.5 mm.

[0030] The exterior trim part shown here only schematically can be a bumper cover, a radiator cover, a tailgate cover, a pillar cover, a door cover, a fender cover, a roof cover, or a spoiler of a motor vehicle, or a component, an assembly, or a part of the aforementioned parts.

[0031] In the Fig. 5 A further process step is shown, which is the arrangement of a luminaire element LQ for emitting light (indicated by the dotted lines) behind the back side B of the base body 2.

Claims

1. Method for producing an outer trim part (1) for a motor vehicle, comprising the following steps: - providing a base body (2) defining the outer trim part (1), wherein the base body (2) consists of a plastic material that is transparent or translucent to light and has an intended visible side (A) and a rear side (B) opposite the visible side (A), wherein a plurality of elevations (3) projecting from the surface of the visible side (A) of the base body (2) are provided and are formed integrally with the base body (2); - applying an opaque coloured layer (4) on the visible side (A) of the base body (2) and on the elevations (3) of the base body (2); characterised in that in a further step, the coloured layer (4) on the elevations (3) is partially or completely removed, so that light can again pass through these regions (5) of the elevations (3), and in that a decorative layer (6) or decorative foil (6) that can be irradiated by light is subsequently applied at least to these regions (5), wherein the decorative layer (6) is applied by means of a pad printing process or the decorative foil (6) is applied by means of a hot stamping process, such that the outer trim part (1) can be partially irradiated by light in these regions (5).

2. Method according to claim 1, characterised in that the coloured layer (4) is partially perforated or completely removed by means of laser radiation.

3. Method according to any one of the preceding claims, characterised in that the decorative layer (6) or the decorative foil (6) can be irradiated by light due to its layer thickness or foil thickness.

4. Method according to any one of the preceding claims, characterised in that the decorative layer (6) comprises a further coloured layer, in particular a further coloured layer having metallic particles or flakes, or the decorative foil (6) comprises a metal foil.

5. Method according to any one of the preceding claims, characterised in that in a further step a transparent or translucent clear lacquer layer (7) and / or an additional protective layer (7) is applied over the coloured layer (4) and the decorative layer (6) or over the coloured layer (6) and the decorative foil (6).

6. Method according to claim 5, characterised in that the additional protective layer (7) comprises, in particular, a silane or a silane compound.

7. Method according to any one of the preceding claims, characterised in that the base body (2) has a wall thickness in the range between 0.8 mm and 5.5 mm.

8. Method according to any one of the preceding claims, characterised in that the outer trim part is a bumper trim or a radiator trim or a tailgate trim or a pillar trim or a door trim or a wing trim or a roof trim or a spoiler of a motor vehicle, or a component or assembly or constituent part of the aforementioned parts.