| 摘要 |
<p>A twin-shell lightweight acoustic trim part (11), in particular a self-supporting vehicle's headliner or a rear parcel shelf comprises a thermoplastic acoustically effective structural composite (5). This composite comprises at least three layers (2, 3, 4), in particular on its front side a skin layer (4), preferably a binder layer made of a thermoplastic non-woven or grid, a stiffening layer (3) made of a non-woven comprising polypropylene and glass fibres, and on its rear side a soft layer (2) consisting of a polyolefin foam. These layers are needle-punched together in order to set a desired airflow resistance R in the range of 200 Nsm -3 to 5000 Nsm -3 . In a preferred embodiment, the twin-shell lightweight acoustic trim part (11) comprises a core layer (8) which contains 50 parts of elastomeric foam sticks, 20 parts of glass fibres, 10 parts of polypropylene fibres material, and 20 parts bicomponent polyester fibres and preferably comprises additional 15% of recycled elastic foam material. This trim part is designed such that the thermoplastic bonded and acoustically effective structural composite (5) allows to absorb the uneven pressure forces of the elastomeric foam material (9) of the core layer (8) in order to achieve a smooth and soft touch feeling.</p> |
