Lightweight dash insulator construction

Abstract

A sound insulating component includes a decoupling layer disposed under a cap layer comprising a thermoplastic cellular foam. Advantageously, the cap layer has sufficient rigidity to maintain a predetermined shape and has an airflow resistance that allows a predetermined amount of airflow through the sound insulating component. In another embodiment, a hybrid sound insulating component includes a cap layer and a decoupling layer with an airflow control layer interposed thereof. A method of making the sound control components is also provided.

1 . A sound insulating component comprising:
 a cap layer comprising a thermoplastic cellular foam, the cap layer having sufficient rigidity to maintain a predetermined shape and having an airflow resistance that allows a predetermined amount of airflow through the sound insulating component; and   a decoupling layer disposed between the vehicle sheet metal and the cap layer, the decoupling layer comprising a sound absorbing material.   
     
     
         2 . The sound insulating component of  claim 1  wherein the thermoplastic cellular foam is an open cell foam. 
     
     
         3 . The sound insulating component of  claim 1  wherein the thermoplastic cellular foam comprises a plastic selected from the group consisting of polyurethane, expandable polystyrene, expandable polypropylene, expandable polyethylene, and combinations thereof. 
     
     
         4 . The sound insulating component of  claim 1  wherein the thermoplastic cellular foam has a volume density from 1.0 to 4.0 lbs/ft3. 
     
     
         5 . The sound insulating component of  claim 1  having a surface density less than or equal to 0.055 lb/ft2. 
     
     
         6 . The sound insulating component of  claim 1  wherein the cap layer has a thickness from 0.04 inches to 0.5 inches. 
     
     
         7 . The sound insulating component of  claim 1  having an airflow resistance from 400 MKS rayls to 4500 MKS rayls. 
     
     
         8 . The sound insulating component of  claim 1  having an airflow resistance from 500 MKS rayls to 3000 MKS rayls. 
     
     
         9 . The sound insulating component of  claim 1  having an airflow resistance greater than MKS 2500 rayls. 
     
     
         10 . The sound insulating component of  claim 5  having an airflow resistance from 3000 MKS rayls to MKS 4500 rayls. 
     
     
         11 . The sound insulating component of  claim 1  wherein the cap layer has a shear modulus from 0.1 MPa to 1.5 MPa 
     
     
         12 . The sound insulating component of  claim 1  wherein the decoupling layer comprises a moldable thermoplastic foam. 
     
     
         13 . The sound insulating component of  claim 12  wherein the moldable thermoplastic foam has a density from 1.0 to 4.0 lbs/ft3. 
     
     
         14 . The sound insulating component of  claim 12  wherein the decoupling layer comprises a component selected from the group consisting of a polyurethane molded or sheet foam, a non-woven vertically lapped PET or PET-cotton fiber blend, and combinations thereof. 
     
     
         15 . The sound insulating component of  claim 12  wherein the vehicle component is selected from the group consisting of dash insulators, wheelhouse covers, quarter trim panels, engine side, vehicle floor pan, trunk components, doors and side coverings. 
     
     
         16 . A sound insulating component comprising:
 a cap layer comprising a thermoplastic cellular foam, the cap layer having sufficient rigidity to maintain a predetermined shape and having an airflow resistance that allows a predetermined amount of airflow through the sound insulating component;   an airflow control layer disposed between the cap layer and the decoupler layer providing the sound insulating component with a predetermined airflow resistance; and   a decoupling layer, the decoupling layer comprising a sound absorbing material.   
     
     
         17 . The sound insulating component of  claim 16  wherein the airflow control layer has an airflow resistance from 300 MKS rayls to 4500 MKS rayls. 
     
     
         18 . The sound insulating component of  claim 17  configured as a hybrid dash insulator. 
     
     
         19 . A method of forming a sound insulating component comprising a cap layer comprising a thermoplastic cellular foam, the cap layer having sufficient rigidity to maintain a predetermined shape and having an airflow resistance that allows a predetermined amount of airflow through the sound insulating component; and a decoupling layer disposed below the cap layer, the decoupling layer comprising a sound absorbing material, the method comprising:
 a) molding a sheet of a thermoplastic cellular foam to a sheet of a sound absorbing material to form the sound insulating component wherein the sheet of thermoplastic cellular foam forms the cap layer and the sheet of sound absorbing material forms the decoupling layer.   
     
     
         20 . The method of  claim 19  wherein the sheet of a thermoplastic cellular foam and the sheet of a sound absorbing material are heated prior to or during step a).