Sound absorbing panel for a vehicle and its method of manufacture

Abstract

A substrate is provided for a sound absorbing panel, the substrate having an acoustic absorptive inner portion and an acoustic flow-resistive outer portion having a first layer on a first side of the inner portion and a second layer on a second side of the inner portion. The inner portion may include a foam material or a fibrous material and each outer portion may include a structural material. The inner portion, also referred to as a core portion, may include at least one of a sound absorbing material, an airbag device and an impact cushion material.

1 . A sound absorbing panel, comprising: 
 a sheet composed of a binding agent and fiber, with the sheet having a first side and a second side with each of the first and second side including a scrim layer; and    a fabric layer bound to one of the first side and second side with a porous adhesive.    
   
   
       2 . The sound absorbing panel of  claim 1 , wherein the binding agent is one of an elastomer material and a thermoplastic material.  
   
   
       3 . The sound absorbing panel of  claim 1 , wherein the other of the first and second side includes a barrier layer.  
   
   
       4 . The sound absorbing panel of  claim 3 , wherein a second scrim layer is bound to the barrier layer.  
   
   
       5 . A substrate for a sound absorbing panel, the substrate comprising: 
 an acoustic absorptive inner portion; and    an acoustic flow-resistive outer portion having a first layer and a second layer, wherein the first layer is on a first side of the inner portion and the second layer is on a second side of the inner portion.    
   
   
       6 . The substrate of  claim 5 , wherein the inner portion includes one of a foam material and fiberglass material.  
   
   
       7 . The substrate of  claim 5 , wherein the outer portion includes a structural material.  
   
   
       8 . The substrate of  claim 7 , wherein the structural material has a weight in the range of about 200 to 1000 grams per square meter.  
   
   
       9 . A sound absorbing panel for a vehicle, the sound absorbing panel comprising: 
 a core portion;    a first outer layer configured to adhere to the core portion; and    a second outer layer configured to adhere to the core portion;    wherein, the core portion is contained between the first and second outer layer.    
   
   
       10 . The sound absorbing panel of  claim 9 , wherein the core portion includes at least one of a sound absorbing material, an airbag device and an impact cushion material.  
   
   
       11 . The sound absorbing panel of  claim 9 , including a scrim layer bound to the core portion by a porous adhesive.  
   
   
       12 . A composite panel for a vehicle, the composite panel comprising: 
 an acoustic absorptive layer; and    an acoustic flow resistive layer bound to the acoustic absorptive layer with a porous adhesive.    
   
   
       13 . The composite panel of  claim 12 , wherein the acoustic absorptive layer is one of a vertically lapped fibrous mat and a sheet comprising a plurality of co-joined beads of material.  
   
   
       14 . The composite panel of  claim 13 , wherein the bead material is polypropylene.  
   
   
       15 . The composite material of  claim 14 , wherein the polypropylene includes a coating that co-joints the beads into a sheet.  
   
   
       16 . A headliner panel for a vehicle comprising: 
 a first layer of acoustic flow resistive material;    a second layer of acoustic absorptive material coupled to the first layer; and    a third layer of acoustic flow resistive material coupled to the second layer,    wherein the acoustic flow resistive material provides a plurality of air passages configured to attenuate sound.    
   
   
       17 . The headliner panel of  claim 16 , wherein the layers are coupled with a porous adhesive.  
   
   
       18 . A method of making a sound absorbing panel, the method comprising the steps of: 
 providing a substrate composed of a binding agent and fiber, with the substrate having a first side and a second side;    providing a fabric layer having a porous adhesive;    placing a scrim layer on the first side of the substrate;    placing the fabric layer on the first side of the substrate;    placing the substrate/fabric layer combination in a three-dimensional forming tool having two mating members; and    applying heat to the substrate/fabric layer combination;    wherein the fabric layer is bound to the substrate, forming the sound absorbing panel.    
   
   
       19 . The method of  claim 18 , wherein the binding agent is one of an elastomer material and a thermoplastic material.  
   
   
       20 . The method of  claim 18 , including the step of adding a colorant containing carbon black to the substrate prior to the step of applying heat.  
   
   
       21 . The method of  claim 20 , wherein the concentration of the carbon black is in the range of 0.0000001 to 1.0% by weight.  
   
   
       22 . A method of making a sound absorbing panel, the method comprising the steps of: 
 providing a substrate composed of an elastomer binding agent and fiber, with the substrate having a first side and a second side;    providing a film adhesive layer;    placing the film adhesive layer on the first side of the substrate; and    moving the substrate/film adhesive layer combination through a hot roll process at a pre-selected speed, temperature and pressure, wherein the film adhesive layer is bonded to the substrate and becomes an open, porous  11  adhesive layer.    
   
   
       23 . The method of  claim 22 , including the step of applying a web adhesive to the substrate prior to moving through the roller.