Composition suitable for making acoustical tiles, comprising gypsum, composition suitable for making acoustical tiles, comprising mineral wool and gypsum and the acoustical tile per se

摘要

The present invention relates to a composition comprising, according to one embodiment, gypsum in an amount less than 58 percent of dry solid components, cellulosic fibers, a lightweight aggregate material and a binding agent, whereby it comprises at least about 15 percent by weight of gypsum and at least about 13 percent by weight of cellulosic fibers. According to another embodiment the composition comprises mineral wool, gypsum in an amount less than 58 percent of dry solid components, cellulosic fibers, a lightweight aggregate material and a binding agent, whereby it comprises at least about at least about 10 percent by weight of mineral wool, at least about 10 percent by weight of gypsum, and at least about 13 percent by weight of cellulosic fibers. The percentages are based on 100 percent of dry solid components without the addition of water. The gypsum/cellulosic fibers composition is combined with a lightweight aggregate material and a binder to form a composition which is used in a water-felting process to manufacture acoustical ceiling tiles and panels. The preferred source of the cellulosic fiber is a composite gypsum/cellulose fiber material which is prepared by mixing the gypsum and cellulosic fiber material with sufficient water to form a dilute slurry which is then heated under pressure to calcine the gypsum, converting it to an alpha calcium sulfate hemihydrate. The resulting composite material comprises cellulosic fibers physically interlocked with calcium sulfate crystals. Another source of both gypsum and cellulosic fibers is waste (scrap) gypsum wallboard. Expanded perlite is the preferred lightweight aggregate material. There is further suggested an acoustical tile manufactured from the above-described composition.