Abstract:
A combination of layered materials for producing a vehicle headliner is provided. The layers include a head impact countermeasure (HIC) layer of co-extruded thermoplastic and a rigid foam layer laid adjacent to the HIC layer and made of a thermoplastic. The layers are subsequently molded together to form the headliner.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates generally to vehicle headliners and particularly to vehicle headliners of laminated construction.  
       BACKGROUND OF THE PRIOR ART  
       [0002]     The interior roof of motor vehicles is commonly outfitted with a vehicle headliner. The vehicle headliner provides several benefits. For example, the headliner provides thermal insulation to help keep the vehicle interior at a comfortable temperature. The headliner also provides acoustical dampening to reduce the level of noise inside the passenger compartment for the vehicle. The headliner also provides a decorative finish to the interior of the vehicle roof.  
         [0003]     Additional structures are often positioned between the vehicle headliner and the roof of the vehicle. These additional structures provide a head impact countermeasure (HIC) to reduce the risk of head injury in the event of an accident. The HIC is generally formed of a plastic and positioned between the headliner and the vehicle roof and operates by deforming under the impact force of a vehicle occupant&#39;s head. During deformation, the HIC dissipates crash energy and thereby provides a degree of protection to the vehicle occupant.  
         [0004]     The HIC structures are commonly positioned between the headliner and the vehicle roof by one or more methods known in the art. These methods include adhering the HIC structure to the headliner and fastening it to the vehicle roof and peripheral structure. Regardless of the method used to position the HIC structure, an undesirable assembly step is introduced to the manufacture of the vehicle or its headliner. Also, undesirable tooling expenses are incurred in creating the requisite molds or other devices used to form and assemble the HIC structures separately from the headliner.  
         [0005]     It is also desirable to improve the recyclability of vehicle headliners. Presently, vehicle headliners are formed from several layers of materials. One of these materials is glass mat or fiberglass. Other adhesives and cross-linked resins such as polyol and isocyanate are also used to secure the layers to each other. These materials, adhesives and resins make recycling vehicle headliners less than desirable since they are difficult, if not impossible, to remove from the headliner prior to recycling. However, when left in, these materials reduce the usefulness of the resultant recycled material.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     In light of these issues identified with the prior art, a vehicle headliner is provided having a combination of layered materials. The layers include a head impact countermeasure (HIC) layer of co-extruded thermoplastic and a rigid foam layer laid adjacent to the HIC layer and made of a thermoplastic. The layers are subsequently molded together to form the headliner.  
         [0007]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0008]      FIG. 1  depicts a cross-section exploded view of a vehicle roof and headliner. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0009]     Turning to  FIG. 1 , a vehicle roof  10  is shown in a cross section taken normal to the axial length of the vehicle. Vehicle roof  10  is of a generally planar shape and formed of metal or composite material, such as fiber reinforced plastic. The roof  10  has exterior surface which is open or exposed to the elements and an interior which is coverable the vehicle headliner assembly as described herein. Beams  12  are provided at the outer edges of the vehicle roof  10  provide rigidity to the roof  10 . A protrusion  14  is provided on a vertical pillar supporting the roof  10 . The protrusion  14  may be used to retain the vehicle headliner as described later herein.  
         [0010]     A HIC layer  20  is provided by a co-extruded polypropylene composite formed into woven fabrics or sheets, such as those which are commercially available under the trademark PURE from LANKHORST-INDUTECH. The HIC layer  20  preferably spans less than the width of the roof  10  and is preferably located so as to result in a spaced relationship from beam  12  after the headliner is molded as described later herein. The spaced relationship provides a crush space between the HIC layer  20  and beams  12  after the headliner is molded and positioned in the vehicle. A rigid foam layer  22  of a material such as polyester or polypropylene  22  is layered beneath the HIC layer  20 . A light blocking layer  24  may be provided above the head HIC layer  20  to preventing the transmission of visible light through the various layers of the headliner assembly. The light blocking layer  24  may also operate as an acoustical damper to reduce the level of noise in the vehicle. Additionally, an acoustical scrim layer  26  may be provided below the rigid foam layer  22 . The acoustical scrim layer operates to also reduce or operates to reduce the level of noise in the passenger compartment of the vehicle. A decorative finish may be provided by foam layer  28  and fabric  30  as an outer layer which is exposed to the vehicle interior. The layers  24 ,  26 ,  28  and fabric  30  are preferably formed of a polyester or polypropylene thermoplastic. To simplify the molding process described later herein, it is preferable that layers  22 ,  24 ,  26  and  28  have a melting temperature approximately equal to the melting layer of the surface of the co-extruded polypropylene used in the HIC layer.  
         [0011]     To produce a vehicle headliner, the layers of the vehicle headliner are placed one upon another inside of a heated mold. The mold has two halves which form an internal cavity conforming to the desired finished shape of the vehicle headliner. Once the desired layers have been placed in the mold, the mold is closed for a predetermined amount of time allowing the desired layers to fuse together into a unitary vehicle headliner assembly.  
         [0012]     Once the completed headliner assembly is removed from the mold it may be trimmed of excess material and openings formed therein using methods known in the art. The unitary headliner assembly may then be installed in the vehicle by placing it against the roof  10  and snapping the periphery of the headliner assembly above the protrusions  14 . The headliner assembly may also be retained by a peripheral trim molding as in known in the art.  
         [0013]     Since the unitary headliner assembly includes a HIC layer  20 , additional vehicle or headliner assembly steps are avoided, as are tooling costs associated with a separate HIC structure.  
         [0014]     A unitary headliner assembly formed from the layers described herein may be recycled by removing the headliner assembly from the vehicle and shredding the entire assembly. The resultant shredded material is composed of polypropylene or polyester thermoplastic, depending on the materials chosen for forming the headliner, and free of glass fibers, adhesives, and resins.  
         [0015]     While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize alternative designs and embodiment for practicing the invention. Thus, the above described preferred embodiment is intended to be illustrative of the invention that may be modified within the scope of the following appended claims.