The interactions between wax and UF resin in medium density fibreboard

Through the use of fluorescently labelled paraffin wax and UF resin, fluorescence microscopy has been used to simultaneously visualise wax and resin components on medium density fibreboard (MDF) fibre. To simulate differing application methods, the wax and resin were applied to fibre either separately or as a mixture. Visualisation on unpressed fibre and in panels suggests the application order can lead to differing wax-resin behaviours and how each interact with fibre. Both qualitative and quantitative analyses of wax and resin distribution on fibre established that the main differences in behaviours were due to wax and occur on pressing. Applying wax first to fibre led to wax droplet agglomeration in panels whereas applying wax after resin or as a mixture appeared to allow wax to be retained as relatively smaller droplets within the resin matrix. This also manifested itself in differences in wax overlap with resin in panels, where a relatively low overlap was observed when applying wax first, despite a substantially higher overlap in unpressed fibre. Application of wax after resin or as a mixture resulted in the wax generally staying with the resin. The observed differences in wax distribution were also correlated with panel cold water soak properties.