Method for steam pressing composite board having at least one finished surface

摘要

In a method for making composite wood products having a market ready finished side, a mat is formed of wood fibers treated with a binder. The mat is loaded into a press cavity formed between two press platens. The first press platen is a conventional hot press platen free of ports. The conventional platen can be smooth or patterned to emboss one surface of the finished product. The other press platen is a steam injection platen which has steam injection ports. The press cavity is sealed and the mat is fully consolidated. A first quantity of steam is injected through the steam injection ports into the mat at a sufficient pressure and for a sufficient time to raise the temperature of at least a portion of a thickness of the mat to 100ºC. The injected steam is allowed to vent from the mat through the steam injection ports, carrying with it trapped air and moisture. A second quantity of steam is injected from the steam injection ports into the mat at a sufficient pressure and for a sufficient time to cure the binder. The second quantity of steam is vented from mat through the steam injection ports before the press cavity is unsealed.