Patent Publication Number: US-2016236451-A1

Title: Method for Manufacturing a Vehicle Outer Surface Component and Vehicle Outer Surface Component

Description:
The invention relates to a method for producing a vehicle outer surface component and to a vehicle outer surface component. 
     A vehicle outer surface component of this type may be a cover for a roof opening system, for example, such as a sunroof or a spoiler roof, or an exterior molding component of a vehicle. 
     DE 10 2008 064 233 A1 describes a door sill panel having an in-mold film, at least sections of which form the surface of the door sill panel and which is made of polycarbonate or a comparable plastic material. A plastic component made of a translucent plastic material is molded onto the back of the in-mold film by injection molding and can be used as a light guide for a light source. Another plastic component made of opaque plastic material is injected onto the plastic component made of translucent plastic. This additional plastic component made of opaque plastic material can form the base component for the door sill panel and can ensure that the door sill panel has sufficient rigidity to withstand the mechanical loads that will be placed on the component. In addition, the front side of the in-mold film that forms the surface portion can be provided with a hard coating of polysiloxane. However, a hard polysiloxane coating of this type is not sufficiently scratch resistant. Scratches in the plastic material cannot be easily repaired. 
     It is the object of the invention to provide a method for producing a vehicle outer surface component as described in the introductory part of the specification that will provide an improved vehicle outer surface component, and to provide such a vehicle outer surface component. 
     This object is attained according to the invention by a method for producing a vehicle outer surface component comprising the following steps:
         preparing a base component made of a thermoplastic material in an injection mold by injecting a thermoplastic material into the injection mold or by placing a prefabricated base component made of a thermoplastic material therein and   injecting a covering layer of a scratch self-healing plastic material into the closed injection mold to coat the base component.       

     The object is further attained by a vehicle outer surface component which has a layered structure comprising at least a base layer and a covering layer, the covering layer being produced from a scratch self-healing plastic material. 
     Advantageous embodiments of the invention are specified in each of the dependent claims. 
     The method according to the invention is therefore characterized in that, for producing a vehicle outer surface component, a coating, in particular a “clear-coat” or transparent coating of a soft plastic material which is scratch self-healing is used and is injected as the covering layer. Self-healing means that when damaged, the plastic material of the covering layer is capable of healing itself or being healed to a full reversal of the damage as long as the molecular structure or the molecular network of the plastic material of the covering layer is not excessively damaged or destroyed when damaged or scratched. Such plastic materials are “soft” in the sense that they yield to damage rather than being injured or scratched—as is the case with hard materials. The restoration properties are dependent on the glass point of the material. By applying heat from external heat sources, the material temperature can be increased so as to induce a self-repair of the material. The material can also be repaired by polishing the surface. 
     Thus with the method according to the invention, rather than placing a finished coated film into the mold as the covering layer, the base layer prepared or produced in the injection mold is coated with the injected covering layer. 
     A base component made of thermoplastic material can be prepared in an injection mold either by injecting a thermoplastic material into the injection mold or by placing a prefabricated base component made of thermoplastic material therein. An emplaced base component can also be coated in the injection mold before the covering layer is injected. 
     The base component is particularly layered, and if it is an emplaced part, it can be a film, e.g. made of plastic or of a compound or composite material, in particular with a PU matrix or resin matrix. 
     It is particularly preferable for the plastic material of the covering layer to be a PUR (polyurethane) or PUA (polyurea) and particularly to be produced with a high-gloss surface. PUR and PUA have self-healing characteristics, even if the covering layer is produced as very thin, e.g. in a layer thickness of 0.1 mm to 2.0 mm. 
     The PUR or PUA is preferably a UV-resistant plastic material. This enables vehicle outer surface components according to the invention to be used permanently without material changes occurring as a result of UV radiation. In the case of transparent roof components, UV radiation is prevented from reaching the vehicle interior. 
     According to an expedient embodiment of the method, before the covering layer is injected an intermediate layer or functional layer can be applied to the base component in the injection mold, so that the covering layer is then applied to this intermediate layer or functional layer. This enables vehicle outer surface components according to the invention having additional functions and characteristics to be produced. 
     Expedient process sequences, both individually and in combinations, are preferred for producing vehicle outer surface components. For instance, the base component and/or the intermediate layer or functional layer can be formed as transparent, translucent or colored and can be formed with a smooth, grained or structured surface and/or can be formed as having text or a graphic pattern. For example, manufacturer names or logos can be introduced into a transparent intermediate layer or functional layer and then covered with a transparent, scratch-proof covering layer. 
     According to a preferred method variant, the base component can be produced with a structured surface and covered with a clear covering layer, so that although the surface structure is protected and covered with a smooth layer, it is still transparent. A structured surface is produced, e.g. by using a correspondingly negatively molded surface of a mold half or turnover plate mold of the injection mold. A structured surface contains, e.g. graining, a printed text or graphic applied to the base component, or an overmolded 3-D structure. 
     The intermediate layer or functional layer can also expediently contain at least one light guide or can be formed as a light guide layer, a design layer or a touch-sensitive layer for generating a signal, or can contain an antenna device or heating wires, or can be formed as a three-dimensional structure in at least one partial area. These configurations may also be used individually or in combination. 
     Finally, the covering layer may also be colorized if transparency is not required and a colored design is desired instead. 
     A vehicle outer surface component according to the invention is produced in particular according to a method as described above or according to any one of claims  9  to  14 . For instance, in the vehicle outer surface component, the functional layer can be a light guide layer or can at least contain a light guide, can be a design layer or a touch-sensitive layer for generating a signal, or can contain an antenna device or heating wires. 
     The vehicle outer surface component can be, e.g. pillar molding, a door sill panel or a fixed or movable, particularly a transparent cover for a roof module. 
    
    
     
       In the following, the invention will be specified in greater detail in the context of embodiment examples of a vehicle outer surface component according to the invention, with reference to the set of drawings. The drawings show: 
         FIG. 1  a sectional view of a vehicle outer surface component according to the invention; and 
         FIG. 2  a sectional view of another vehicle outer surface component. 
     
    
    
       FIG. 1  shows a schematic sectional representation of a vehicle outer surface component  1 , e.g. in the form of a cover for a roof module. A base layer  2  made of a thermoplastic material is formed with a structured upper side  3  or surface. Base layer  2  is coated with a covering layer  4  which is made of a self-healing plastic, e.g. PUR or PUA, and particularly comprises clear plastic, so that structured upper side  3  is transparent. Surface  5  of covering layer  4  may be formed as smooth and high-gloss or also as structured. 
     A vehicle outer surface component  1  as shown in  FIG. 2  contains, on base layer  2 , an intermediate layer or functional layer  6 , onto which covering layer  4  is applied. Intermediate layer or functional layer  6  contains, e.g. heating wires  7  of a heating device. 
     The individual features of the invention disclosed in the description in the context of the embodiment examples and in the figures may be combined in any technically expedient arrangements and configurations with the subject matter of the invention in its general form. 
     LIST OF REFERENCE SIGNS 
       1  vehicle outer surface component 
       2  base layer 
       3  structured upper side 
       4  covering layer 
       5  surface 
       6  intermediate layer or functional layer 
       7  heating wire