Acoustically absorbent ceiling tile having barrier facing with diffuse reflectance

Abstract

An acoustically absorbent ceiling tile 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 facing has highly diffuse reflectance of light, and a reflectance of greater than about 86%. The use of the facing improves the acoustic absorption of ambient sound at frequencies below about 1200 Hz. The facing provides a barrier to moisture and particles including microorganisms so that the ceiling tile is suitable for use in environments in which cleanliness is critical.

1 . A ceiling tile comprising:
 a core of acoustically absorbing material having two major surfaces; and   a facing for covering the core on at least one major surface thereof, the facing comprising a flash spun plexifilamentary film-fibril sheet having a coherent surface, having a basis weight of no greater than about 140 g/m 2 , 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 and having a light reflectance of greater than about 86%.   
   
   
       2 . The ceiling tile of  claim 1 , wherein the acoustic absorption of the ceiling tile at a frequency below about 1200 Hz is at least about 5% higher than the acoustic absorption of the ceiling tile without the facing. 
   
   
       3 . The ceiling tile of  claim 1 , wherein the delamination resistance of the flash spun sheet is at least about 0.028 N/m. 
   
   
       4 . The ceiling tile of  claim 1 , wherein the facing is perforated. 
   
   
       5 . The ceiling tile of  claim 1 , wherein the flash spun plexifilamentary film-fibril sheet comprises particulate filler having a refractive index greater than the refractive index of the polymer. 
   
   
       6 . The ceiling tile of  claim 1 , wherein the core of acoustically absorbing material has a noise reduction coefficient of between about 0.3 and about 0.9 and the noise reduction coefficient of the ceiling tile is approximately equivalent to the noise reduction coefficient of the core. 
   
   
       7 . The ceiling tile of  claim 1 , wherein the facing has a Parker surface smoothness not less than 6 micrometers. 
   
   
       8 . The ceiling tile of  claim 1 , wherein the facing has a tensile strength of at least about 20 N/2.54 cm. 
   
   
       9 . The ceiling tile of  claim 1 , wherein the facing comprises a graphical image printed thereon. 
   
   
       10 . The ceiling tile of  claim 1 , wherein the facing is free of nutrients that support growth of microorganisms. 
   
   
       11 . The ceiling tile of  claim 1 , wherein the facing has a log reduction value of at least about 2. 
   
   
       12 . The ceiling tile of  claim 1 , wherein the facing comprises a polymer selected from the group consisting of polyethylene and polypropylene. 
   
   
       13 . A method of improving acoustic absorption and light reflectance in an environment comprising:
 (a) providing a ceiling tile comprising a core of acoustically absorptive material covered by a facing of flash spun sheet having 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 and having a light reflectance of greater than about 86%; and   (b) positioning the ceiling tile within the environment to cause ambient sound to be absorbed and light to be reflected by the ceiling tile.