Hardboard

Hardboard consists of lignocellulosic fibre (e.g. wood, straw, bagasse) of thickness of up to 8 mm and a density ≥ 900 kg/m³. Hardboard is manufactured using heat and pressure. Most hardboards are produced in a "wet process", where a fibre moisture content of more than 20 % at the forming stage is common. In these hardboards, one face is rough due to the use of a mesh screen for dewatering. Boards manufactured in the "dry process" exhibit smooth surfaces on both sides. The panels are bonded primarily by felting of the fibres and their inherent adhesive properties. Usually, only small amounts of a synthetic binder are added to the fibres. By incorporating additives (e.g. hydrophobic agents, fungicides, fire retardants) or post-treatments certain properties of the board can be altered. Due to their visco-elastic behaviour boards can be shaped during processing, and bends with a radius less than 25 cm are possible.