Abstract:
A plastic composite element for a motor vehicle. The plastic composite element includes an outer covering and a separating means placed between flexible and rigid foam layers. The separating means prevents the rigid foam from penetrating the flexible foam and/or prevents a deformation of the outer covering.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional of U.S. application Ser. No. 10/204,677 filed Nov. 7, 2002, hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a plastic composite element, such as an interior lining element for a motor vehicle.  
         [0004]     2. Background Art  
         [0005]     U.S. Pat. No. 5,851,457 discloses a method for producing a seat cushion.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention provides a method for producing a plastic composite element and a corresponding plastic composite element that may be produced at low costs. The plastic composite element may include an outer covering, flexible foam, rigid foam, and a separating means.  
         [0007]     The use of the term flexible foam is to be understood as a distinction over the rigid foam which is also to be applied, and is to express that the flexible foam is more flexible than the rigid foam. Therefore, the flexible foam may also include so-called semi-rigid foams, such as polyurethane foams having a specific weight of e.g., 0.11 to 1.18 g/m 3 . The rigidity of the flexible foam can be adjusted by the mixing ratio of the components, which are normally two, and can be adapted to the demands made on the comfort and/or safety of the respective application, the shape of the composite element, the thickness of the flexible foam, and/or the thickness and rigidity of the rigid foam.  
         [0008]     The outer covering may consist of a plastic material, e.g., a deep-drawn polyvinyl chloride (PVC), and comprise a relief and/or decoration on the visible surface. Typical reliefs may include grained imitation leathers. The outer covering may be a shaped part which can be prefabricated accordingly.  
         [0009]     The separating means between flexible and rigid foam may be produced by deep drawing, deep-drawn parts of plastics being suitable for reasons of costs, e.g. parts made of acrylic butadiene styrene (ABS), polyvinyl chloride (PVC) or polystyrene (PS). The initial thickness of the shaped part used as the separating means may be between 0.1 and 0.7 mm, depending on the material used and the shape. The separating means may prevent a change which is detrimental to aesthetics, haptics, shape, and/or safety that may occur in the flexible foam and/or the outer covering or the composite element due to the compressive stresses arising during the back-foaming with rigid foam and possibly becoming visible upon removal of the composite element from the mold.  
         [0010]     For lining purposes the outer covering is placed into a correspondingly formed lower mold and the flexible foam material which forms the flexible foam is then applied to the back side of the outer covering. Depending on the temperature of the flexible foam material, the shape and the environment, it will take some time, normally a few seconds, until a foaming and thus an increase in volume of the flexible foam material occurs. Prior to or during foaming of the flexible foam material the shaped part is brought into contact with the flexible foam material. The shaped part may be mounted on a correspondingly shaped upper mold and held in the upper mold; for instance, by vacuum application at the back side, locking or clamping.  
         [0011]     Further advantages, features and details of the invention will become apparent from the claims and the following description in which one embodiment is described in detail with reference to the drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  shows a detail of the production of a plastic composite element according to the invention; and  
         [0013]      FIG. 2  shows a cross section through a plastic composite element according to the invention. 
     
    
     DETAILED DESCRIPTION  
       [0014]      FIG. 1  shows a detail of the production of a plastic composite element  1  according to the invention, namely the lining of the outer covering  2  with a flexible foam  3  and the application of a shaped part  4  as a separating means between the flexible foam  3  and the rigid foam  5  to be applied subsequently. To this end a predeterminable amount of the flexible foam material, which after foaming yields a PU semi-rigid foam with a specific weight between 0.11 and 0.18 g/cm 3 , is applied to the back side  2   a  of the outer covering  2  which is put into a lower mold  6  and has previously been produced as a deep-drawn part from polyvinyl chloride (PVC), possibly by using the illustrated lower mold  6 , and which is provided on its surface  2   b  with a decoration and/or a relief.  
         [0015]     Subsequently, the upper mold  7 , including the mounted shaped part  4  that has been produced by deep drawing from an ABS plastic material with an initial thickness adapted to the mechanical properties required, and the lower mold  6  are joined while the flexible foam  3  is foaming and still deformable. At a temperature of the lower and upper molds  6 ,  7  of e.g., about 45° C. and a suitable flexible foam material, the foaming process starts and thus the increase in volume of the flexible foam material after about 10 to 12 seconds after application to the outer covering  2 . Lower and upper molds  6 ,  7  remain closed until the complete hardening of the flexible foam  3 . After the mold has been opened, the composite of outer covering  2 /flexible foam  3 /shaped part  4  is lined in a further step of the method with a rigid foam  5 .  
         [0016]     In the illustrated embodiment, the shaped part  4  is fixed by vacuum application at the back side to the upper mold  7  which to this end comprises connection channels  8  between a vacuum chamber  9 , which can be brought into operative communication with a vacuum pump (not shown) and can be aerated, if necessary, and the mold surface  7   a  of the upper mold  7  that is oriented towards the back side  4   a  of the shaped part  4 . Alternatively or in addition, the shaped part  4  can also be fixed by clamping or locking to the upper mold  7 .  
         [0017]      FIG. 2  is a cross-sectional view showing a plastic composite element  1  according to the invention, which may be an element of an interior trim for a door of a motor vehicle. The outer covering  2  may be prefabricated by deep drawing. On its surface  2   b  directed to the interior of the motor vehicle, it may comprise a leather-like texture or graining. In an area of the interior trim of the door that may form a ledge of the door window, the outer covering is lined with the flexible foam  3 . The hardness of the flexible foam  3  and the thickness of the flexible foam layer are adapted to the respective application, in particular to the demands made on comfort and/or security.  
         [0018]     The flexible foam  3  may be lined with the rigid foam  5  with intermediate placement of the shaped part  4  which has also been prefabricated by deep drawing and consists of an ABS plastic material having an initial thickness of 0.3 mm. The shaped part  4  is connected on its edge portions in planar contact with the outer covering  2  and by the flexible foam  3  to said covering, so that the rigid foam  5  is reliably prevented from penetrating the area of the flexible foam  3  between the outer covering  2  and the shaped part  4 . Outside the shaped part  4  and in particular in an area in which the demands made on comfort and/or safety do not require a flexible foam  3 , the rigid foam  5  can come into direct contact with the outer covering  2  and directly line said covering.  
         [0019]     While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.