Patent ID: 7332114

Claim:
A continuous process for manufacturing a sound absorbing tile having an NRC above 0.5 and made from a slurry comprising, on a wet basis about 53 to about 68 wt % quick setting cement, about 17% to about 48 wt % water, about 0.05 to about 5 wt % fibers and about 0.01 to about 10 wt % foaming agent, said tile having pores comprising interconnected voids and having a porosity from 75 to 95% by volume of said tile, said process comprising the steps of: (i) mixing the cement, the water, the foaming agent but without incorporation of a prefabricated foam with the fibers in an amount of from 0.05 to 5% by weight based on the final weight of the tile into a slurry, under first mixing conditions; subsequently (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry under second mixing conditions, using a blender comprising a barrel equipped with a rotating shaft, wherein the shear is lower under the second mixing conditions than under the first mixing conditions; (iii) subsequently depositing said slurry on at least one moving facer comprised of a glass mat to form said tiles or precursor thereof from said cellular slurry; and (iv) finally allowing said cellular slurry to set into the tile or a precursor thereof; and (v) optionally finishing the tile or precursor thereof.