Properties of flame-retardant high density fiberboard synergized with industrial by-product

High density pine fiberboard (HDF) with good fire performance was successfully prepared by using flame retardants of industrial by-product(mainly composed of aluminum trihydrate Al(OH)₃), zinc borate (2ZnO·3B₂O₃·3.5H₂O) and boric acid (H₃BO₃). The mechanical properties, flame retardancy and char morphology were characterized and analyzed. The results show that there is a good synergistic effect on the flame-retardancy between Al(OH)₃ and 2ZnO·3B₂O₃·3.5H₂O and H₃BO₃ which can enhance the char formation up to 22.2% and reduce the total heat release with a dop of 32%, while the mechanical properties are well maintained. The limited oxygen index (LOI) of the flame retardancy board can reach up to 36.4% and the vertical burning test can reach V-0.