Ultralight trim composite
An ultra light, noise reducing composite ( 1 ) comprises an acoustically transparent, light weight film ( 6 ) between an underlay layer ( 5 ) and an air flow resistance layer ( 4 ). This composite allows to easily tune the acoustic properties by balancing the absorption and sound transmission behaviour of the composite ( 1 ). This air flow resistance layer ( 4 ) has an air flow resistance of between 500 Ns/m3 and 10,000 Ns/m3 and an area mass between 200 g/m2 and 3,000 g/m2. The underlay layer ( 5 ) has a stiffness value in the range between 100 Pa and 100,000 Pa. The light weight film ( 6 ) may consist of a synthetic foil and preferably has a thickness of 0.01 mm.
1. An ultralight trim composite ( 1 ) comprising a first acoustically effective layer ( 4 ) and a second underlay layer ( 5 ), characterized in that for the balancing of the absorption and sound transmission behaviour of the composite, the first acoustically effective layer ( 4 ) has an air flow resistance R between 500 Ns/m 3 and 10,000 Ns/m 3 and has an area mass m A between 200 g/m 2 and 3,000 g/m2, the second underlay layer ( 5 ) has a very low compression force deflection modulus, i.e. a stiffness value S D in the range between 100 Pa and 100,000 Pa and in addition comprises an acoustically transparent, very thin and light weight film ( 6 ) between the second underlay layer ( 5 ) and the first acoustically effective layer ( 4 ), which film interacts with this underlay layer ( 5 ) in the manner of an acoustic foil absorber ( 9 ).
2. Composite according to claim 1 , wherein the second underlay layer ( 5 ) is a backfoamed layer.
3. Composite according to claim 1 , wherein the second foam underlay layer ( 5 ) consists of a foam slab.
4. Composite according to claim 3 , wherein the foam slab comprises an open pored skin.
5. Composite according to claim 1 , wherein the film ( 6 ) is perforated in order to increase the absorption properties.
6. Composite according to claim 5 , wherein the film ( 6 ) is microperforated.
7. Composite according to claim 1 , wherein the film ( 6 ) is unperforated in order to increase the transmission loss.
8. Composite according to claim 1 , wherein the first acoustically effective layer ( 4 ) has a thickness of 0.5 mm to 8.0 mm.
9. Composite according to claim 8 , wherein the first acoustically effective layer ( 4 ) has an area weight of about 1 kg/m 2 .
10. Composite according to claim 1 , wherein the second foam underlay layer ( 5 ) acting as a decoupler layer, has a thickness of about 20 mm.
11. Composite according to claim 1 , wherein the film layer has a thickness of about 0.01 to 1.0 mm.