Making water resistant gypsum board by adding an aqueous wax emulsion to an aqueous slurry of a calcium sulfate material and host particles

摘要

A process for making a gypsum board with improved water resistance involves adding an aqueous wax emulsion to an aqueous slurry of calcium sulphate and host particles. The emulsion is stable under which e slurry is maintained. The wax-containing slurry is passed onto a flat porous forming surface where most of the water is drained off to form a filter cake. The filter cake is pressed to remove additional water and form a board. The board is then fried to remove the remaining free water, and to heat the core of the board to a temperature sufficient to melt the wax.