Low density acoustical gypsum boards having a perforated cover sheet that have good sound absorption properties and are generally clear of falling gypsum dust. The invention optionally provides a cover sheet having a pattern producing a textured visual effect particularly when viewed from a distance. The acoustical gypsum boards can be produced on modified existing gypsum board lines.

 
Web www.patentalert.com

> Dual injection of two polymeric filtration aids for gypsum removal from phosphoric acid/gypsum slurry

~ 00345