Low thickness sound absorptive multilayer composite

Abstract

A sound absorptive multilayer composite having an air-impermeable barrier, an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅔ the final composite thickness, and a semipermeable airflow-resistive decorative membrane having an airflow resistance of about 500 to about 4000 mks Rayls can provide improved acoustic performance while maintaining a low thickness.

1 . A sound absorptive multilayer composite comprising in order: 
 a) a semipermeable airflow-resistive decorative membrane having an airflow resistance of about 500 to about 4000 mks Rayls,    b) an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about 2/3 the total composite thickness, and    c) an air-impermeable barrier.    
     
     
         2 . A composite according to  claim 1  wherein the composite has a cavity depth at least 90% of the total composite thickness, with the cavity depth being measured from the air- impermeable barrier innermost side to the membrane outermost side.  
     
     
         3 . A composite according to  claim 1  wherein the composite has a cavity depth at least 95% of the total composite thickness, with the cavity depth being measured from the air- impermeable barrier innermost side to the membrane outermost side.  
     
     
         4 . A composite according to  claim 1  wherein the membrane has an airflow resistance of about 500 to about 1500 mks Rayls.  
     
     
         5 . A composite according to  claim 1  wherein the membrane is colored or textured to provide a decorative appearance.  
     
     
         6 . A composite according to  claim 1  wherein the membrane comprises a nonwoven web.  
     
     
         7 . A composite according to  claim 1  wherein the membrane comprises knit or woven fabric comprising microdenier yarns.  
     
     
         8 . A composite according to  claim 1  wherein the membrane comprises multicomponent fibers.  
     
     
         9 . A composite according to  claim 1  wherein the membrane comprises split or splittable bicomponent fibers.  
     
     
         10 . A composite according to  claim 1  wherein the core has a thickness at least about ¾ the total composite thickness.  
     
     
         11 . A composite according to  claim 1  wherein the core has an airflow resistance less than about 2000 mks Rayls.  
     
     
         12 . A method for making a multilayer sound absorptive composite comprising: 
 a) providing a stack of layers comprising in order an air-impermeable barrier, an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅔ the final composite thickness, and a semipermeable airflow-resistive decorative membrane having an airflow resistance of about 500 to about 4000 mks Rayls, and    b) laminating the stack of layers together under sufficient heat and pressure to form a unitary sound absorptive multilayer composite.    
     
     
         13 . A method according to  claim 12  wherein the composite has a cavity depth at least 90% of the total composite thickness, with the cavity depth being measured from the air- impermeable barrier innermost side to the membrane outermost side.  
     
     
         14 . A method according to  claim 12  wherein the composite has a cavity depth at least 95% of the total composite thickness, with the cavity depth being measured from the air- impermeable barrier innermost side to the membrane outermost side.  
     
     
         15 . A method according to  claim 12  wherein the membrane has an airflow resistance of about 500 to about 1500 mks Rayls.  
     
     
         16 . A method according to  claim 12  wherein the membrane is colored or textured to provide a decorative appearance.  
     
     
         17 . A method according to  claim 12  wherein the membrane comprises a nonwoven web.  
     
     
         18 . A method according to  claim 12  wherein the membrane comprises knit or woven fabric comprising microdenier yarns.  
     
     
         19 . A method according to  claim 12  wherein the membrane comprises multicomponent fibers.  
     
     
         20 . A method according to  claim 12  wherein the membrane comprises split or splittable bicomponent fibers.  
     
     
         21 . A method according to  claim 12  wherein the core has a thickness at least about ¾ the total composite thickness.  
     
     
         22 . A method according to  claim 12  wherein the core has an airflow resistance less than about 2000 mks Rayls.