Method for finishing motor vehicle parts and products produced therefrom

Abstract

A motor vehicle part provided with decorative element. The method of providing the decorative element comprises applying a plurality of paint layers to an electro-deposition coated panel, wherein the

Description

Introduction The present invention relates to a method of finishing a motor vehicle part using a laser, to motor vehicle parts obtained using the method of the invention and to motor vehicles, or components, comprising the motor vehicle part. Background to the Invention It is known to provide decoration to the surface of cars, including the doors, windows, bonnet, roof, bumpers, grilles, fenders and boot lid. Decoration is often added to confer uniqueness on the motor vehicle e.g. to make it personalised. Personalisation is especially desirable in higher end luxury vehicles, in which considerable attention is paid to the aesthetics of the entirety of the vehicle and uniqueness is highly desired. One of the ways in which decoration can be added to the exterior surface is via the use of stickers or decals. Another known way of decorating the exterior surface is by using a stencil and spray painting e.g. graphics onto the body work. Of course, whole sections of the exterior bodywork can also be sprayed if a change of colour is desired. A disadvantage associated with each of the above-described methods of decoration is that they are applied on top of the existing paint work and thus create an uneven surface finish which can be aesthetically displeasing, and thereby undesirable, especially for purchasers / owners of higher end vehicles. Furthermore, none of the known methods of decoration described above allow designs to be incorporated into the external surfaces of motor vehicles. Accordingly, it is an aim of the present invention to provide an alternative method of finishing a motor vehicle part so as to have a decorative element displayed thereon. A further aim is to provide an improved method of finishing a motor vehicle part having a decorative element displayed thereon, where the displayed decorative element is incorporated into the surface of the motor vehicle part providing an even surface finish. A still further aim is to provide a motor vehicle part having a decorative element displayed thereon, made using the method of the invention, and motor vehicles and components incorporating the motor vehicle part. Summary of the Invention Accordingly, the invention provides a method of finishing a motor vehicle part such that it has displayed thereon a decorative element; which method comprises: (i) applying a plurality of paint layers to an electro-deposition coated panel, wherein the plurality of paint layers comprise at least a first and a second basecoat layer; (ii) using a laser to selectively remove one or more paint layers, wherein the laser does not remove the electro-deposition coat. The motor vehicle part may be an internal or external part. In preferred embodiments it is an external part, for example it is part of, or is incorporated into, the door, bonnet or roof of a motor vehicle, especially that of a car. More generally, the invention relates to the use of a laser to finish a motor vehicle part such that it has displayed thereon a decorative element, by selectively removing one or more paint layers. In use of the invention a finish can be obtained that is more even than hitherto achievable. It becomes possible to incorporate a wide range of designs into the surface decoration of the motor vehicle. Details of the Invention The invention hence provides a method of decorating a motor vehicle part; which method comprises: (iii) applying a plurality of paint layers to an electro-deposition coated panel, wherein the plurality of paint layers comprise at least a first and a second basecoat layer; (iv) using a laser to selectively remove one or more paint layers, wherein the laser does not remove the electro-deposition coat. In a typical use of the invention, the laser can be directed or applied with such power and / or for such duration that in one region of decoration one or more paint layers are removed and in another region a different number of paint layers are removed; for example, in one region of decoration one paint layer is removed and in another region two paint layers are removed. Removing a given layer exposes the layer below and so if the exposed and thus now visible layers differ in any respect, e.g. reflectivity, colour, whether gloss, silk or matt etc, varied and intricate designs are creatable. On top of the lasered surface one or more translucent or transparent final or top coats can be applied to finish the decorating process. An advantage of the method of the present invention is therefore that it allows detailed, decorative elements to be incorporated into the surface of vehicle parts with the result that the finished surface is even and thereby aesthetically pleasing to the eye and to the touch. In some embodiments of the invention, more than two basecoat layers may be present. In a preferred embodiment of the invention, the plurality of paint layers comprise at least a first, a second and a third basecoat layer. The decorative element may comprise first and second regions and the method may comprise removing one or more paint layers in a first region and removing a different number of paint layers in a second region. Different top surfaces of underlying paint layers can thus selectively be exposed and become visible, creating the decoration. In embodiments, the first and second basecoat layers, and the third basecoat layer where present, are different colours. ln embodiments a method is provided comprising removing different numbers of layers of paint in different regions to expose underlying basecoats of different colours, thereby creating the decorative element. More specifically, the method may comprise removing one paint layer in a first region and removing two paint layers in another region. A basecoat layer is a layer of paint that contains colour, although the specifics of the colour are immaterial to the invention. Examples of suitable colours include white, black, silver, grey, red, blue, green, orange, yellow, purple and pink. Different coloured effects are also achieved by variation in hue, shade, reflectivity and other effects. Typically, basecoats in adjacent layers have different appearance, whether as a result or colour and / or hue and / or reflectivity and / or paint effects, etc. Decoration is applied to the motor vehicle part by selectively removing different numbers of layers to expose layers of different appearance. There are generally four main categories of basecoat: solid, metallic, pearlescent and matte. Solid paints only contain the colour and are thus often the cheapest and easiest type of paint to apply. Metallic paints are similar to solid paints but contain a small amount of powdered metal. The type of metal can vary although typically aluminium is used. The metal particles reflect more incident light than solid paint which creates a sparkling effect commonly referred to as the “metallic” effect. Pearlescent paints use ceramic crystals rather than metal particles, which both reflect and refract light. One of the effects achieved is that referred to as the “two tone” effect. Matte paints are typically grey or black and reduce or prevent the reflection of light giving the car a flat appearance which is extremely popular in high end luxury vehicles. When particularly bright colours, for example yellow, are used as basecoats, it is often necessary to apply several basecoat layers in order to achieve the desired colour. Referring to the layers of paint on the panel, the first basecoat layer is the basecoat layer closest to the electro-deposition coated panel - note it may be adjacent to the panel or there may be one or more intermediate layers. The first and second basecoat layers, and indeed further basecoat layers (e.g. a third basecoat layer) where present, may be the same colour. Alternatively, the first and second basecoat layers, and indeed further basecoat layers (e.g. a third basecoat layer) where present, can be different colours allowing multi-coloured decoration of the panel, and this is preferred. In the examples described herein, used for illustration, the first basecoat layer was white and the second basecoat layer was black. In the method of the invention, the basecoat layers may be applied directly on top of each other. Alternatively, the basecoat layers may be separated by one or more different paint layers. For example the first and second basecoat layers may be separated by one or more clearcoat layers. In a preferred embodiment of the invention, at least one clearcoat layer exists between the first and second basecoat layers. A clearcoat layer is a layer of paint that doesn’t contain any colour or pigment. Rather, it may be a glossy and translucent, preferably substantially transparent, layer that when applied as the final paint layer forms the final interface with the environment. It may be a lacquer. A clearcoat layer can be between paint layers and can additionally or alternatively be the top or final layer facing the external environment (subject to optional finishing such as polishing, etc). A clearcoat layer applied as a final layer suitably contains one or more UV inhibitors which prevent UV rays from the sun fading the colour of the vehicle. In a preferred embodiment of the invention, the final paint layer is a clearcoat layer. In some embodiments, multiple clearcoat layers may be present underneath the final clearcoat layer. In the examples described herein, two clearcoat layers were applied on top of the second basecoat layer. In a preferred embodiment of the invention, at least two clearcoat layers are applied on top of each of the first and second basecoat layers. When painting external vehicle parts, routinely the first basecoat layer is applied on top of a primer layer. The primer layer serves several purposes: it serves as a leveller, it prevents the vehicle from corrosion, heat differences, bumps, stone-chips and UV light and it also improves the ease of application of the next paint layer preventing flaking and / or chipping. In a preferred embodiment of the invention, the motor vehicle part comprises at least one primer layer between the electro-deposition coated panel and the first basecoat layer. An electro-deposition coated panel is a component, not limited by shape, to which an electro-deposition coating has been applied. Electro-deposition coating is conventional and very generally is or comprises an immersion wet paint finishing process that uses electrical current to attract a paint product to the surface of a component. Known electro-deposition coating systems apply an electrical charge to either the component to be coated or the paint forming the coating. The component is then lowered into a paint bath and the paint particles are attracted to the component forming an even, continuous, low profile film over the entire surface of the component. The process continues until the desired film thickness is reached. After several rinsing steps, the paint is oven cured. The method of the invention uses a laser to selectively remove paint layers. It is preferred that the coating achieved by the electro-deposition process remains intact after laser treatment of its surface. The laser does not remove the coating, meaning the coating or at least a functional residue thereof remains. It is preferred that the laser application is controlled so the laser does not penetrate to or into that coating -penetration of the electro-deposition coat can cause flaking or peeling. When a primer layer is present between the electro-deposition coated panel and the first basecoat layer, it is preferred that the laser does not remove the primer layer, meaning the primer layer or at least a functional residue thereof remains. That is, it is preferred that the laser application is controlled so the laser does not penetrate to or into the primer layer. The type of laser used to remove the paint layers is not a feature of the invention. Examples of suitable lasers include CO2 type, Fibre type and UV type lasers. The laser may be operated manually or via a robot. The creation of some decorative elements may be further aided by use of a stencil to guide the laser. In some instances the laser treatment may represent the final step in the method of finishing of the motor vehicle part. In other instances, the method may comprise an additional step of applying at least one further outer paint layer post laser treatment. Preferably, the at least one further outer paint layer comprises a clearcoat layer. In general, the overall thickness of the plurality of paint layers applied to the electrodeposition coated panel should not exceed about 1 mm, preferably about 800pm, even more preferably about 600pm, and most preferably about 450pm. The invention is not limited by the type of decorative element displayed on the external vehicle part; however, for the purpose of example only, the decorative element may comprise a picture, image, lettering, numerals or combinations thereof. The decorative element may also comprise differences in colour. The motor vehicle part may be an internal or external part, though preferably it is an external part. The motor vehicle part may be any part of a motor vehicle, wherein the motor vehicle is preferably a car. For example, the external part may be a door, a bonnet, a roof, a bumper, a grille, a fender, a boot lid, or any component thereof, of a motor vehicle which is preferably a car. In one preferred embodiment of the invention, the part is a vehicle door or a component thereof. In a further preferred embodiment of the invention, the part is a vehicle roof or a component thereof. ln a still further preferred embodiment of the invention, the part is a vehicle bonnet or a component thereof. Accordingly, also provided by the invention is a motor vehicle door comprising the motor vehicle part of the invention. Further provided is a motor vehicle roof comprising the motor vehicle part of the invention. Still further provided is a motor vehicle bonnet comprising the motor vehicle part of the invention. Although the motor vehicle can be any motor vehicle, preferably the motor vehicle is a car. As such, also provided by the invention is a car comprising the decorated vehicle part of the invention. Examples The invention is now illustrated in the following example with reference to the accompanying drawing in which: Fig. 1 is a photograph of an electro-deposition coated panel to which the method of the invention has been applied. Referring to figure 1, a panel (1) is shown which is A6 in size. The panel is an electrodeposition coated panel to which several paint layers were applied. The first paint layer applied was a white primer, followed by, in consecutive order, an arctic white basecoat layer, a clearcoat layer, a black diamond basecoat layer and two further clearcoat layers. Polish was then applied. A Speedy 400 flexx laser (Trotec) was used to selectively remove paint layers from the aforementioned panel. The resolution of the laser was set at 500 dpi and the speed velocity at 50. Several different power settings were tested within the range of the laser power output. A range of power settings cut through and completely removed the black diamond basecoat layer to expose the artic white basecoat layer, without removing that white layer and without penetration to the electro-deposited layer, which was left intact by the lasering. 5 Following this demonstration of selective removal of one or more paint layers, a decoration can be applied onto a painted car panel that has been painted with, in order from the starting panel: say, at least a primer layer, a first basecoat, a clearcoat, a second basecoat, a clearcoat and a third basecoat. The laser is applied in a first region to remove the third basecoat - this exposes the colour of the second basecoat. The 10 laser is applied in a second region to remove the third basecoat and the intervening clearcoat and the second basecoat - this exposes the colour of the first basecoat. The resultant decoration is made of three differently coloured regions and is then given a final, top clearcoat layer which helps to produce an even finish. 15 CM

Claims

1. A method of finishing a motor vehicle part such that it has displayed thereon a decorative element; which method comprises:(i) applying a plurality of paint layers to an electro-deposition coated panel, wherein the plurality of paint layers comprise at least a first and a second basecoat layer;(ii) using a laser to selectively remove one or more paint layers, wherein the laser does not remove the electro-deposition coat.

2. A method according to claim 1, wherein the plurality of paint layers further comprises a third basecoat layer.

3. A method according to claim 1 or claim 2, wherein the decorative element comprises first and second regions and the method comprises removing one or more paint layers in a first region and removing a different number of paint layers in a second region.

4. A method according to any previous claim, wherein the first and second basecoat layers, and the third basecoat layer where present, are different colours.

5. A method according to any previous claim, comprising removing a different number of layers of paint in different regions to expose underlying basecoats of different colours, thereby creating the decorative element.

6. A method according to any previous claim comprising removing one paint layer in a first region and removing two paint layers in another region.

7. A method according to any previous claim, wherein at least one clearcoat layer exists between the first and second basecoat layers.

8. A method according to any previous claim, wherein at least one primer layer exists between the electro-deposition coated panel and the first basecoat layer.

9. A method according to claim 8, wherein the laser does not remove the primer layer.

10. A method according to any previous claim, comprising applying a clearcoat layer to the decorative element as a final layer.

11. A method according to any previous claim, wherein the decorative element comprises a picture, image, lettering, numerals or combinations thereof.

12. A method according to any previous claim, wherein the decorative element comprises differences in colour.

13. A method according to any previous claim, comprising the additional step of applying at least one clearcoat layer post laser treatment.

14. A method according to any previous claim, wherein the motor vehicle part is a external motor vehicle part.

15. A method according to any previous claim, wherein the motor vehicle part is a vehicle door or a component thereof.

16. A method according to any previous claim, wherein the motor vehicle part is a vehicle roof or a component thereof.

17. A method according to any previous claim, wherein the motor vehicle part is a vehicle bonnet or a component thereof.

18. A method according to any previous claim, wherein the vehicle is a car.

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