Use of fiber material from chemothermomechanically processed waste particleboard and fiberboard

Subject Chemo-thermo-mechanical pulps (CTMP) were made from waste particle- and fibreboards. Medium density fiberboards (MDF) were made from industrial refiner fibers in combination with the CTMP using urea-formaldehyde resin as a binder. The physical properties and the formaldehyde content of the MDF were determined. The results reveal that MDF made from CTMP of waste particle- and fibreboards meet the standards according to EN 622-5, type MDF. The bending strength and internal bond of MDF made from industrial TMP is higher compared with MDF from chemo-thermo-mechanical pulps from waste panels. However, the thickness swelling of MDF made from pulps derived from waste panels is clearly lower compared with that of MDF made from industrial TMP. Furthermore, MDF made from pulps derived from waste panels show a lower formaldehyde content than MDF from virgin fibers. It seems that residues of chemicals from the pulping process (CTMP) act as a formaldehyde scavanger.