Acoustic absorber with barrier facing

Abstract

An acoustic absorber includes a core of acoustically absorbing material having two major surfaces, and a facing for covering the core on at least one major surface. The facing comprises a porous flash spun plexifilamentary film-fibril sheet having a coherent surface and comprising a plurality of pores having a pore diameter between about 100 nm and about 20,000 nm and a mean pore diameter of less than about 20,000 nm. The use of the facing improves the acoustic absorption of ambient sound at a frequency below about 1200 Hz. The facing provides a barrier to moisture and particles including microorganisms so that the absorber is suitable for use in environments in which cleanliness is critical.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention relates generally to an acoustic absorber, particularly for use in building interiors, that is highly resistant to the penetration of water and fine particles including microorganisms and is essentially sound transparent in the voice frequency range.[0003]2. Description of the Related Art[0004]Acoustically absorbing materials are known in the art for use reducing the amount of noise and / or reverberation within a given space, such as a building interior. Acoustically absorbing materials, i.e., materials having a high absorption coefficient, reduce noise by absorbing acoustic energy. There are various types of acoustically absorbing materials. One of the most common types utilizes fibrous materials to dissipate sound energy by friction within the interfibrous voids. In general, the greater the thickness and the higher the density of the absorber, the greater is the acoustic absorption of the absorber, partic...

AI Technical Summary

Benefits of technology

[0011]a facing for covering the core on at least one major surface, the facing comprising a porous flash spun plexifilamentary film-fibril sheet having a coherent surface, having a basis weig

Problems solved by technology

Therefore, known solutions to achieve appreciable absorption at low frequencies tend to be expensive.

While the fiber-based sound absorbers are generally inexpensive and are an effective solution for sound absorption over a wide frequency range, they have inherent disadvantages, such as possible release of particulates into the air, collection of dust and harboring bacteria and mold on their surface and inside the voids, as the area is not cleanable.

Facings which are acoustically reflective undesirably contribute to the ambient noise.

Thin, commonly 6-35 micrometers, impervious film facings are acoustically transparent in the low and mid frequencies, but they are acoustically reflective at high frequencies, as such they do not allow sound waves to pass.

Thin film facings also have a serious drawback of not being durable enough to sustain everyday use and should be a

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