| abstract |
A wet laid basemat for an acoustical ceiling tile comprising on a dry weight basis, 50% or more mineral wool fiber, including shot, less than 9% binder, and between 5 and 20% chopped strand glass fiber, and, optionally, minor amounts of other constituents, whereby the chopped strand glass fibers serve to promote and/or maintain voids in the mat such that the dry basemat has a density of between about 7-1/2 to about 10-1/2 lbs. per cubic foot and an NRC substantially greater than.55. |