Multilayer automotive trim part for noise attenuation comprising at least two fibrous layers (10, 30) and at least one air permeable intermediate film layer (20) between the at least 2 fibrous layers (10, 30), whereby the trim part is air permeable, and at least one of the fibrous layers (10, 30) is a mixture of fibers consisting of 10 to 40% of binder fibers, 10 to 70% of recycled fibers and 10 to 70% of self-crimped fibers and wherein the total amount of said fibers adds to 100% by weight.
The invention relates to a multilayer sound attenuating trim part for a vehicle, in particularly a trim part or cladding used for the interior of a vehicle, for instance as inner dash or as part of the floor covering or for the exterior of a vehicle, for instance as trim part or cladding in the engine bay area or as part of an under body trim component as well as to the method of producing such part.
Sound attenuation is an important factor in the design of a car. For sound attenuation fibrous materials are used in mass spring acoustic systems as well as in single or multilayer absorbing systems.
The choice of a particular sound insulating material for a given application is determined not only by its ability to attenuate sound but by other considerations as well. These include cost, weight, thickness, fire resistance, etc. Well-known sound attenuating materials include felts, foams, compressed fibrous felt materials, glass wool or rock wool, and recycled fabrics including shoddy materials.
For instance U.S. Pat. No. 5,298,694 discloses an acoustical insulating web to be used as an absorbing layer, comprising melt-blown microfibers and crimped bulking fibres in a weight ratio of about 40:60 to about 95:5. The crimped bulking fibers disclosed are mechanically crimped fibers or thermally crimped fibers. These types of crimp are mainly used to aid the production process of the fibrous material felt layer, however they do not have a prolonged effect on the product performance during its use.
Read more: Fibrous automotive cladding
