TEMPERATURE BEHAVIOUR IN PARTICLEBOARD DURING PRESSING

Abstract

The objective of the present work was to investigate the behaviour of core and face temperatures of particleboard glued with 8% tannin-formaldehyde adhesive. The boards were manufactured with three replication per treatment, with density of 0,7 g/cm³ and 27 kgf/cm² of pressing specific pressure. Pine flakes (40, 75 and 110 mm long and 0,5 and 1,0 mm thick) and eucalypt particles were used and two pressing temperatures (140 and 180ºC) along with two mat moisture content (17 and 21%) were employed. The curves of temperature rise with pressing time indicated a fast temperature rise during the first 100 seconds of pressing, remaining at a plateau possible after reaching water boiling temperature. The temperature increased again, but on a more gradual form, after the lost mat moisture. It was possible to observe that mat formed by flakes of larger thicknesses showed faster initial temperature rise. The main factor that influenced the temperature behaviour at the board core was the mat moisture content. The higher the mat moisture content, the faster the temperature rise.

Keywords

• elevação da temperatura
• chapas aglomeradas
• tanino-formaldeído