Patent ID: 8365862

Claim:
A method of manufacturing a sound absorption material, the method comprising: forming a low density fibrous web to act as a porous bulk absorber, the low density fibrous web having a density of more than about 10 kg/m 3 and less than about 120 kg/m 3 , and containing a proportion of bi-component fibers, each bi-component fiber having a core material and a sheath material around the core material, the sheath material having a lower melting point than the core material; applying a thin facing layer directly to the low density fibrous web, wherein the facing layer is a non-adhesive type film that is adhesively compatible with the sheath material; heating the low density fibrous web to a temperature sufficient to soften the sheath material of at least some of the bi-component fibers; and pressing the facing layer and low density fibrous web together under low pressure such that at least part of the facing layer directly contacts the softened sheath material of at least some of the bi-component fibers to form an adhesive bond between the facing layer and the fibrous web, and the fibrous web remains a low density fibrous web after release of said low pressure.