Patent ID: 7906176

Claim:
A method of manufacturing a fire retardant structural board, the method comprising the steps of: (a) providing a structural mat constructed of randomly oriented natural fibrous material having a weight, thickness, and first and second surfaces; (b) orienting the structural mat to expose its first surface; (c) applying a first application of triglycidyl polyester binder and sodium borate pentahydride onto the first surface and into the thickness of the structural mat; (d) heating the structural mat to only partially cure the binder appliedonto the first surface; (e) turning the structural mat over to expose its second surface; (f) applying a second application of triglycidyl polyester binder and sodium borate pentahydride onto the second surface and into the thickness of the structural mat; (g) heating the second surface of the structural mat to cure the binderapplied onto the second surface and compressing the mat to a desired thickness; and (h) coating the second surface of the structural mat with a liquidcomposition that includes sodium borate penta hydride; (i) flash drying the liquid composition wherein the resulting fire retardant structural board having a class A burn rate certification as specified in the NFPA 101 life safety code or its equivalent; and (j) wherein steps are performed in sequential order: (a), (b), (c), (d), (e), (f), (g), (h), and (i).