| abstract |
Gypsum/fiber board, especially for use as floor board, is fabricated by preparing a binder consisting of at least 60% by weight of calcium sulfate alpha hemihydrate, and at most 35% by weight calcium sulfate beta hemihydrate, the balance, if any, inert material such as grinding residues from finished plaster board, in an amount of 100 parts by weight of the binder to 20 parts by weight of fiber, especially cellulose fiber or a mixture of cellulose fiber from scrap paper with reinforcing fiber. This dry mixture combined is with water in an amount such that no water can be expressed from the prepared mix by the subsequent pressing step and the prepared mix is then pressed in a peripherally-closed form such that the finished gypsum/fiber board will have a raw density of at least 1.5 g/cm2. |