Patent Publication Number: US-2005136212-A1

Title: Porous interior trim system and method of manufacturing same

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a porous interior trim system for a vehicle, and to a method for making the trim system.  
      2. Background Art  
      A known method of making an interior trim system, such as a flooring system, involves applying an air-impermeable polyethylene backing layer onto a carpet layer including tufted fibers woven into a spun bond polyester backing. The polyethylene backing layer binds the fibers to the polyester backing, thereby improving durability of the flooring system.  
      One known method of making an air-permeable flooring system includes applying a latex coating onto a back surface of a carpet layer. The latex coating wicks into the back surface of the carpet layer, thereby creating an air-permeable coating on the carpet layer. A disadvantage of this method, however, is that material and equipment costs are significant.  
     SUMMARY OF THE INVENTION  
      Under the invention, a method of making a porous interior trim system for a vehicle includes applying polyethylene particulate to a back side of a porous carpet layer; heating the carpet layer and the particulate; and molding the carpet layer and a porous layer to achieve a desired shape. Moreover, the polyethylene particulate forms a porous coating that is in direct contact with the porous layer.  
      Further under the invention, a method of making a contoured, porous sound insulating floor system for use with a motor vehicle includes applying polyethylene particulate to a back side of a porous carpet layer having fibers extending from a primary backing; heating the carpet layer and a porous, generally planar padding layer; and molding the carpet layer and the padding layer to achieve a desired non-planar configuration. The polyethylene particulate forms a porous coating on the back side of the carpet layer that bonds the fibers to the primary backing. The porous coating further bonds the carpet layer to the padding layer such that the porous coating is in direct contact with the padding layer.  
      A porous sound insulating floor system according to the invention includes a porous carpet layer having a primary backing and multiple fibers attached to the backing. The system further includes a porous coating on the backing and a porous layer in direct contact with the porous coating. The porous coating is formed from polyethylene particulate applied to the backing. Moreover, the porous coating bonds the fibers to the backing and further bonds the porous layer to the carpet layer.  
      While exemplary products and method of making the products in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic cross-sectional view of an interior trim system in accordance with the invention, the trim system including a carpet layer, an air-permeable or porous coating attached to the carpet layer, and a porous layer attached to the porous coating; and  
       FIG. 2  is a schematic view of an arrangement for making the trim system in accordance with the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)  
       FIG. 1  shows an interior trim system  10 , such as a flooring system or carpet system, that is positionable adjacent to a vehicle part  11 , such as a floor pan, of a motor vehicle. As additional examples, trim system  10  may be a package shelf covering, trunk liner, door panel covering, or other covering or lining system for use with the vehicle.  
      The trim system  10  includes an air-permeable, porous carpet layer  12  and an air-permeable, porous coating  14  attached to the carpet layer  12 . In the embodiment shown in  FIG. 1 , the trim system  10  also includes an air-permeable, secondary porous layer  16 , such as a padding layer, attached to and in direct contact with the porous coating  14 .  
      The carpet layer  12  has an appearance side or surface  18  that faces toward a vehicle interior, and a concealable back side or surface  20 . While the carpet layer  12  may have any suitable configuration, in the embodiment shown in  FIG. 1 , the carpet layer  12  includes natural and/or synthetic fibers  22 , such as tufted nylon fibers, that may be woven into, or otherwise connected to, a primary backing  24 , such as a porous, spun bond polyester backing. As another example, carpet layer  12  may include non-woven fibers provided with or without a backing.  
      The porous coating  14  is formed from polyethylene particulate that is applied on the back surface  20  of the carpet layer  12  and bonded to the carpet layer  12 , as explained below in detail. The porous coating  14  includes multiple voids or pores  26  that allow air to pass through the porous coating  14 . While the porous coating  14  may have any suitable thickness, in one embodiment of the invention, the porous coating  14  has a thickness in the range of 0.5 to 2 millimeters.  
      The porous layer  16  may be attached to the carpet layer  12  by the porous coating  14 . Furthermore, the porous layer  16  may comprise any suitable material including foam and/or fibers, such as natural and/or synthetic fibers. In the embodiment shown in  FIG. 1 , the porous layer  16  is a lightweight padding layer that comprises synthetic fibers, such as polyethylene terephthalate fibers, and/or cotton fibers mixed with binder fibers. As another example, the porous layer  16  may comprise one or more paper layers, filter media layers and/or padding layers.  
      Referring to  FIG. 2 , a method according to the invention for making the trim system  10  will now be described. While the trim system  10  may be manufactured using any suitable system,  FIG. 2  shows an exemplary system or arrangement, such as production line arrangement  28 , for manufacturing trim system  10 . Production line arrangement  28  includes a particulate application station  30 , a heating station  32  and a molding station  34 . Furthermore, the stations  30 - 34  are preferably, but not necessarily, disposed at the same location. The production line arrangement  28  may also include one or more conveyor systems  36  for transporting components within and/or between the stations  30 - 34 .  
      In the embodiment shown in  FIG. 2 , carpet layer  12  is provided to the particulate application station  30  as a completed carpet layer that was manufactured either at the same location or at a location different from the location of the production line arrangement  28 . The carpet layer  12  may also include a sintered polyethylene coating that was applied at the carpet manufacturing location using a conventional manufacturing process.  
      At the particulate application station  30 , polyethylene particulate, such as powder, chopped fibers, chips, flakes and/or pellets, is applied to the back surface  20  of the carpet layer  12 . In the embodiment shown in  FIG. 2 , for example, polyethylene particulate is deposited from a hopper  38  on the carpet layer  12  so that the loose particulate may make direct contact with the primary backing  24  and the fibers  22  over the entire back surface  20 .  
      Next, the carpet layer  12 , with the polyethylene particulate deposited thereon, is transferred to heating station  32  either manually or automatically. The carpet layer  12  is then heated in any suitable manner, such as in a first convection oven  40 , such that the polyethylene particulate at least partially melts to form porous coating  14 . Porous coating  14  may also seep or otherwise pass into the primary backing  24 .  
      The porous layer  16  may also be heated in any suitable manner at the heating station  32 , at the same time as the carpet layer  12 , such as in a second convection oven  42 . Alternatively, carpet layer  12  and porous layer  16  may be heated together, such as in the same oven.  
      Next, the carpet layer  12 , with porous coating  14 , and the porous layer  16  are transferred to molding station  34  where the carpet layer  12  and porous layer  16  may be combined together and molded into a desired shape to form the trim system  10 . Moreover, the porous coating  14  forms the interface between the carpet layer  12  and the porous layer  16 .  
      In the embodiment shown in  FIG. 2 , molding station  34  includes a mold  44  having first and second mold sections  46  and  48 , respectively, that each have a non-planar mold surface. The mold  44  is movable between an open position, shown in  FIG. 2 , and a closed position (not shown) for compressing together the carpet layer  12  and the porous layer  16 , and for shaping the carpet layer  12  and the porous layer  16  into a three dimensional molded shape. Alternatively, one or both mold sections  46  and  48  may have a planar mold surface.  
      One or more additional layers may also be positioned between the mold sections  46  and  48 , such that the additional layers may be molded with and attached to the carpet layer  12  and porous layer  16 . For example, one or more additional layers may be attached to the porous layer  16  during the molding process, such as with an adhesive. Alternatively, one or more additional layers may be attached to the porous layer  16  prior to positioning the porous layer  16  between the mold sections  46  and  48 .  
      In the embodiment shown in  FIG. 2 , the porous layer  16  has a planar configuration when initially positioned between the mold sections  46  and  48 , such that the porous layer  16  and carpet layer  12  may be simultaneously molded into a desired shape. Alternatively, the porous layer  16  and/or any additional layers may be molded in a separate molding operation such that each layer has a three dimensional molded shape, such as a shape corresponding to the mold surfaces of mold sections  46  and  48 , prior to positioning such layer or layers between the mold sections  46  and  48 .  
      Upon sufficiently cooling, either during or after the molding step, the porous coating  14  bonds the fibers  22  to the primary backing  24 , thereby locking the fibers  22  in place. The porous coating  14  further bonds the carpet layer  12  to the porous layer  16  such that the porous coating  14  is in direct contact with the porous layer  16 . As a result, no additional adhesive is required between the porous coating  14  and the porous layer  16 , although additional adhesive may be used.  
      After the molding step, the trim system  10  may be trimmed, such as with a water jet, knife, or any suitable cutting device, if desired. Alternatively, the trim system  10  may be trimmed during or prior to the molding step.  
      With the process described above, the carpet layer  12  and the porous layer  16  may be attached together and molded into a desired shape in one molding step. Furthermore, heating of the carpet layer  12  and/or porous layer  16  may also be performed in the mold  44 , such that the heating step may be performed simultaneously with or immediately prior to the molding step. For example, a heating fluid such as air or steam may be introduced into the mold  44  to heat the carpet layer  12  and/or the porous layer  16 . As another example, one or both mold sections  46  and  48  may be heated in any suitable manner, such as with a heating fluid, so that one or both mold sections  46  and  48  may be used to heat the carpet layer  12  and/or the porous layer  16 . In addition, application of the polyethylene particulate to the carpet layer  12  may occur while the carpet layer is positioned in the mold  44 .  
      Under the invention, the entire trim system  10  may be formed as an air-permeable system. For example, trim system  10  may be formed as an air-permeable flooring system that is configured to maximize sound absorption. While each layer of the trim system  10  may have any suitable air-permeability, in one embodiment of the invention, the carpet layer  12  has an airflow resistance in the range of 0 to 500 mks Rayls, the porous coating  14  has an airflow resistance in the range of either 0 to 500 mks Rayls or 2,500 to 10,000 mks Rayls, the porous layer  16  has an airflow resistance in the range of 0 to 500 mks Rayls, and the entire trim system  10  has an airflow resistance in the range of either 0 to 500 mks Rayls or 2,500 to 10,000 mks Rayls.  
      Furthermore, the air-permeability of the porous coating  14  may be controlled based on the particle size, type and/or amount of the polyethylene particulate applied to the carpet layer  12 . As a result, the porous coating  14  may be formed to have any suitable airflow resistance.  
      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.