Method of sound-deadening for vehicles

摘要

For under hood sound-deadening of vehicles a molded sheet (14) of impregnated non-woven fabric sheet material having a weight in the range 0.5 to 0.75 kg/m2 and a density in the range of 350 to 425 kg/m3 is used. The material includes a blend of polyester staple fibers having an average decitex in the range 2.5 to 4.0 dtex typically 3.2 dtex. The impregnant includes 10 to 35% by dry weight carboxylated styrene-butadiene copolymer in which the styrene content is not less than 55%, 5 to 10% by dry weight carboxylated styrene-butadiene copolymer in which the styrene content is not more than 50%, 50 to 70% by dry weight mineral filler, and up to 3.5% by dry weight melamine formaldehyde resin. Pigment may also be added. The fabric sheet material is preferably clipped to the hood underside to provide a small air gap between the material and the hood, but alternatively the sheet material may be bonded by adhesive to the hood underside.