Patent ID: 7732043

Claim:
A ceiling tile comprising a slurry formed mat of a nominal thickness of between about ½ inch and about ¾ inch and having at least 75% mineral wool content and 3% binder by weight, the binder being distributed substantially throughout the thickness of the mat and serving to rigidify the mineral wool fibers, and a binder enhancement zone on a face side of the mat, the zone having a binder content per unit thickness substantially greater than the binder content per unit thickness of a main portion of the mat whereby approximately ⅕ to ¼ of the total binder content is in the binder enhancement zone and the remaining respective approximately ⅘ to ¾ binder content is distributed in the mat out of the binder enhancement zone whereby the hardness of the zone is greater than the hardness of the main portion of the mat such that the durability of the tile in resisting physical damage is increased while the overall binder content of the tile can be reduced and consequently the costs of the tile can be reduced.