Evaluations of the effects of different flame retardants combinations on particleboards produced using urea–formaldehyde resin

Nowadays, using flame-retardant chemicals is gaining importance in chipboard production. Melamine resins to produce chipboard are preferred to provide flame retardancy properties with a cost of approximately 2.5 times the urea–formaldehyde (UF) resin. In this study, the UF resin to produce the chipboard was preferred due to its economical availability. To improve the flame retardancy properties of the chipboard, phosphate-based and inorganic flame retardants were used in the chipboards. In chipboard production, oak, pine, poplar, sawdust, urea–formaldehyde resin as adhesive, flame retardant chemicals like triphenyl phosphate (TPP), ammonium polyphosphate (APP), and calcium gluconate (CaG) were used. Flame retardant chemicals were added to chipboards in single and double compositions and prepared by pressing method. Mechanical (tensile, bending, and surface strength), physical (humidity, density, formaldehyde emission), and fire (limiting oxygen index (LOI), cone calorimeter, and UL-94 vertical) tests were performed on wooden boards. It has been observed that the use of different types of flame retardant and their combinations in chipboard does not significantly change the mechanical properties. It was seen that the free formaldehyde emission rate decreased by using flame retardant added compared to the control sample. The chipboard samples with added flame-retardant chemicals have entered the V-0 rating in the UL-94. LOI values of the chipboard samples containing 50% CaG-50% APP and 50% TPP—50% CaG were observed as 29.7% and 29.8%, respectively. Besides, the highest heat release rate (HRR) reduction was obtained in the chipboard sample containing 50% CaG—50% APP.