Abstract: A porous facing material comprises a nonwoven web containing interfused thermoplastic elastomeric fibers. The interfused thermoplastic elastomeric fibers comprise a blend of at least two thermoplastic elastomers of a different tensile modulus. The nonwoven web has a basis weight in a range of from 100 to 1500 grams per square meter and a thickness of from 0.2 to 3.5 millimeters, and is abrasion resistant. Acoustically attenuating composites, which have an airflow resistance of from 100 to 10000 mks rayls, and which include a porous facing material secured to a porous backing, are also disclosed. Methods of making and using the foregoing articles are also disclosed.

Abstract: A new acoustic insulating sheet material comprises in laminar assembly a) a primary sound absorbing sheet, and b) a dense porous membrane that i) has an air-flow resistance of about 5000 rayls or less and ii) has an Acoustic Value Ratio as defined herein of at least 3000. Preferably, the membrane is about 200 micrometers or less in thickness, and more preferably is about 150 micrometers or less in thickness. Also, the Acoustic Value Ratio is preferably at least 7,000. The described membrane can also be used alone to acoustically insulate a space, e.g., by mounting it in planar array over an air gap and in position to attenuate noise from a noise source.