Effect of Boron Addition to Adhesive and/or Surface Coating on Fire-Retardant Properties of Particleboard

Mustafa Kemal Yalinkiliç, Yuji Imamura, Munezoh Takahashi, Zafer Demirci


Boron added to urea formaldehyde (UF) resin during manufacture of board from waste tea leaves was combined with a fire-retardant coating system containing boron to further reduce combustibility. Boric acid (BA) and borax (BX) were used as boron compounds separately or in a mixture of 5:1 (BA:BX, w/w) in aqueous solutions of UF resin. A BA+BX mixture was also added to a 40% aqueous solution of trimethylolmelamine (TMM) (as a binding agent) and applied to the board surface. Fire-retardant properties were determined according to the Japanese Industrial Standard JIS A 1322.

Thickness swelling and water absorption levels were not changed remarkably by boron addition to UF resin, while static bending and internal bond strengths were reduced to some extent. However, BX addition suppressed the adverse effect of BA on board strength, probably by buffering its acidic pH to almost neutral levels, while BA reduced the glowing or smoldering effect of BX. Panels with or without added boron showed no ignition after the flame source was cut off after 13 min. Surface coating with the boron-added TMM improved fire retardance. To limit the reduction of strength properties due to boron addition to the resin, fire-retardant surface coating can be applied to impart a required level of fire protection.


Boron;bio-based composite;fire retardance;surface coating;particleboard;UF;waste tea leaves

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