Sound-Absorbing Lining for Motor Vehicles, Particularly Engine Hood Lining

Abstract

The invention relates to a self-supporting, sound-absorbing lining for the engine bonnet of motor vehicles, comprising at least one layer of open-cell foamed material which on at least one side is covered with a covering nonwoven, an open-pored coating that connects the covering nonwoven to the layer of foamed material being applied to at least one side of the layer of foamed material. In order to improve this type of lining with regard to its dimensional stability at temperatures of up to 180° C. and when in a damp environment and without using nonwovens made from synthetic mineral fibres, the invention proposes that the coating be formed from a powder mixture that consists of at least one thermoplastic component, at least one cross-linking component and mineral microbodies, preferably hollow microbodies.

1 . Self-supporting lining ( 1 ,  1 ′,  1 ″) that absorbs airborne sound, for motor vehicles, particularly in the form of an engine hood lining or engine-side face wall lining, having at least one open-cell foam material layer ( 2 ;  2 . 1 ,  2 . 2 ) that is laminated to a non-woven fabric cover ( 3 ,  4 ) on at least one side, whereby an open-pore coating ( 5 ) that connects the non-woven fabric cover with the foam material is applied on at least one side of the foam material layer, wherein the coating ( 5 ) is formed from a powder mixture that is composed of at least one thermoplastic component, at least one cross-linking component, and mineral micro-bodies.  
   
   
       2 . Lining according to  claim 1 , wherein at least two foam material layers ( 2 . 1 ,  2 . 2 ) are present, wherein the coating ( 5 . 3 ) is also applied between at least two of the foam material layers ( 2 . 1 ,  2 . 2 ).  
   
   
       3 . Lining according to  claim 1 , wherein the foam material layer ( 2 ) or foam material layers ( 2 . 1 ,  2 . 2 ) are formed from duroplastic foam material.  
   
   
       4 . Lining according to  claim 1 , wherein it is laminated to a non-woven fabric cover ( 3 ,  4 ) on both sides.  
   
   
       5 . Lining according to  claim 1 , wherein the coating ( 5 . 1 ,  5 . 2 ) is applied to both sides of the foam material layer ( 2 ).  
   
   
       6 . Lining according to  claim 1 , wherein the non-woven fabric cover ( 3 ) or the non-woven fabric covers ( 3 ,  4 ) are formed from polyester fibers or mixtures containing polyester fibers.  
   
   
       7 . Lining according to  claim 1 , wherein the coating ( 5 ;  5 . 1 ,  5 . 2 ,  5 . 3 ) is composed of 15-45 wt.-% thermoplastic plastic, 8-25 wt.-% duroplastic binder, and 50-70 wt.-% mineral micro-bodies.  
   
   
       8 . Lining according to  claim 1 , wherein the coating ( 5 ;  5 . 1 ,  5 . 2 ,  5 . 3 ) is composed of 20-30 wt.-% thermoplastic plastic, 10-20 wt.-% duroplastic binder, and 55-65 wt.-% mineral micro-bodies.  
   
   
       9 . Lining according to  claim 1 , wherein the mineral micro-bodies are formed from hollow mineral micro-bodies.  
   
   
       10 . Lining according to  claim 1 , wherein the thermoplastic component of the coating ( 5 ;  5 . 1 ,  5 . 2 ,  5 . 3 ) is a plastic from the group of polyolefins, copolyesters, or copolyamides.  
   
   
       11 . Lining according to  claim 1 , wherein the cross-linking component of the coating ( 5 ;  5 . 1 ,  5 . 2 ,  5 . 3 ) is formed from phenolic resin, melamine resin, melamine/phenolic resin, and/or epoxy resin.  
   
   
       12 . Lining according to  claim 1 , wherein the coating ( 5 ) contains 2-6 wt.-% phenolic resin binder and 8-15 wt.-% melamine resin binder.  
   
   
       13 . Lining according to  claim 1 , wherein the coating ( 5 ,  5 . 1 ,  5 . 2 ,  5 . 3 ) is applied to the foam material layer ( 2 ) or the non-woven fabric cover ( 3 ,  4 ) with a weight per surface area in the range of 50 to 200 g/m 2 .  
   
   
       14 . Lining according to  claim 1 , wherein the micro-bodies have a grain size less than/equal to 400 μm, preferably less than/equal to 300 μm.  
   
   
       15 . Lining according to  claim 1 , wherein it is free of mineral fibers, particularly free of glass fibers.  
   
   
       16 . Lining according to  claim 1 , wherein the foam material layer ( 2 ;  2 . 1 ,  2 . 2 ) and/or the non-woven fabric cover ( 3 )/the non-woven fabric covers ( 3 ,  4 ) are made to be hydrophobic and/or oleophobic.