摘要 |
<p>PROBLEM TO BE SOLVED: To obtain building board products of high strength from the waste material of wood cement by cutting the waste of cement plates reinforced with wood substance and binding the cut pieces with a synthetic resin binder and forming them into plates. SOLUTION: The waste cement plates reinforced with wood substance are cut into pieces 1-3 mm thick, 2-10 mm wide and 5-20 mm long. These pieces are mixed with 5-25 wt.% of a synthetic resin binder, when necessary, other materials, too. The starting mixture is scattered on the mold plate, pressed with a pressure of 2-5 Mpa at 100-200 deg.C for 10-30 minutes to form the objective building plates. The synthetic resin binder is preferably a thermally setting binder, for example, an alkali-resistant powdery resol type phenol resin or a moisture-curable urethane prepolymer. The pieces of the waste material may be further smaller and the products of high strength can be obtained, even when the amount of the binder is not increased.</p> |