US Patent 10167230 Ultra stable tile backer board formulation

A tile backer board has 29 wt % to 40 wt % of a magnesium oxide dry powder containing 80 wt % to 98 wt % of magnesium oxide, 14 wt % of 18 wt % of a magnesium chloride dissolved in water; 0.1 wt % to 10 wt % of a stabilizing material with a phosphorus-containing compound, reacting into an amorphous phase cementitious material. The phosphorus-containing compound is a phosphorous acid (A) or a phosphoric acid (B). 0.1 wt % to 30 wt % of an aggregate is added and then a reinforcing component is mixed in or the cement is poured onto the reinforcing component forming a tile backer board.