Combustion properties of medium-density fiberboards coated by a mixture of calcite and various fire retardants

Abstract

The properties of wood and wood-based panels may be affected by many factors, such as fungi, insects, humidity, and fire. For reducing these influences, wood and woodbased panels can be treated with various chemicals, including a PVC-based layer and various dyes, or coated with wood veneers or foils, depending on the structure of the material and its intended use. Generally, the panels are coated in order to increase the areas in which they can be used, improve their strength characteristics, and enhance their aesthetic appeal (Thoemen et al. 2010;İstek et al. 2010).The coating process is a technique in which various materials can be applied to the surfaces of paper, paper board, wood, and wood panels. The materials used for coating may include clay, calcite, some other pigments, an adhesive mixture, or some other suitable materials. Thus, the coatings that are used improve the properties of the coated materials, such as their aesthetic appeal, smoothness, opacity, quality of the applied colors, or other surface properties. The term 'coating process' is also used with reference to lacquered and varnished wood and wood panels (Lavigne 1986). Currently, clay and calcite are commonly used as coating materials for many applications because they increase the strength and the physical and surface properties of the materials to which they are applied. Fire retardants (FRs), such as borax (BX), boric acid (BA), and zinc borate (ZB), can be added to the coating mixture to increase the desirable combustion properties of materials, depending on their intended uses (Casey 1961). Generally, chemicals used as FRs may affect many properties of materials. It was found that FRs combined with boron reduced the mechanical properties and surface quality of wood panels (Baysal et al. 2006;Ustaömer 2008). Generally, FRs do not prevent the burning of wood and wood panels. Some of them do increase the temperature at which combustion can occur. Thus, the rate at which a fire will propagate is decreased due to the increased ignition temperature and the time required to reach that temperature (Örs et al. 1999). Some FRs, when in wood, reduce the temperature, resulting in thermal degradation of the wood. The result is pyrolysis gases that are less combustible (and more char), which then results in less flaming combustion to propagate the flames. Therefore, for increasing the combustion performance of wood and wood panels, they must be coated with various

Investigation of some surface properties and thermogravimetric analysis of veneer sheets treated with fire retardants

“…The highest residual char amounts were obtained from ammonium sulfate for poplar and Scots pine; zinc borate for beech; borax for alder,. Boron materials as fire retardant chemicals were investigated by several researchers during the last decades (Tomak et al 2012, Tondi et al 2014, Salman et al 2014, Yuksel et al 2014, Istek et al 2013, Roth et al 2007, Jin et al 2014, Qu et al 2011. Parallel to the previous studies, our results showed that the impregnation of boron materials (Zinc borate and borax) enhanced the resistance against fire (Uner et al 2016).…”

Effects of Coating with Calcite together with Various Fire Retardants on the Fire Properties of Particleboard

“…Compared with similar studies using MDF (Istek et al 2013;Özçifci and Okcu 2008), the values determined in the present study were higher. The effect of BA on the fire property of the particleboard was greater than that of the BX, MEL, and DOL.…”

Thermal analysis of Oriental beech wood treated with some borates as fire retardants

“…The highest residual char content (75%) was achieved for the sample impregnated with 4,70% DOT among the all treated samples. Fire retardancy of borates were investigated by several researchers during the last decades (Tomak et al 2012, Tondi et al 2014, Salman et al 2014, Yuksel et al 2014, Istek et al 2013, Roth et al 2007, Jin et al 2014, Qu et al 2011). Parallel to the previous studies, our results showed that the impregnation of borates (BX, BA, BA+BX (1:1), BA+BX (7:3) and DOT) enhanced the resistance against to fire.…”