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 industria l refiner fibers in combination with the CTMP using urea-formaldehyde resin as a binder. The physical properties and the formaldehyde content of the M DF were determined. The results reveal that MDF made from CTMP of waste par ticle- 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 h igher compared with MDF from chemo-thermo-mechanical pulps from waste panel s. However, the thickness swelling of MDF made from pulps derived from wast e panels is clearly lower compared with that of MDF made from industrial TM P. 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.