Patent ID: 8133354

Claim:
An acoustic panel comprising: from 0 to about 75 wt % mineral wool; more than 0 to about 30 wt % inorganic materials selected from the group consisting of calcium sulfate, calcium carbonate, clay and mixtures thereof; more than 0 to about 15 wt % binder selected from the group consisting of starch, latex, a combination of starch and cellulosic fibers, kraft paper gel and mixtures thereof; from about 25 to about 70 wt % perlite; from about 10 to about 40 wt % cellulosic fiber; wherein about 25 wt % to about 100 wt % of the cellulosic fiber and about 20 wt % to about 80 wt % of the inorganic materials are provided by paper sludge obtained from pulp and paper processing waste, said paper sludge including cellulosic fiber and inorganic materials selected from the group consisting of clay, calcium carbonate and mixtures thereof.