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CTMP versus TMP in moisture resistant bonded MDF

: Roffael, E.; Dix, B.; Hennecke, U.; Krug, D.; Stephani, B.

BioComposites Centre, Bangor:
Tenth Panel Products Symposium 2006. Proceedings : Llandudno, Wales, UK, 11, 12, 13 October 2006
Bangor, Gwynedd, 2006
ISBN: 1-84-220-094-1
European Panel Products Symposium <10, 2006, Llandudno>
Fraunhofer WKI ()
Mitteldichte Faserplatte (MDF); Feuchtebeständigkeit; Hydrolyseresistenz; Aufschlussverfahren; Thermomechanischer Aufschluss (TMP); chemo-thermomechanischer Aufschluss; physikalisch-technologische Eigenschaft; medium density fibreboard (MDF); moisture resistance; hydrolysis resistance; pulping method; thermomechanical pulp (TMP); chemo-thermomechanical pulps (CTMP); physical-technological property

Nowadays pulps for the industrial manufacture of medium density fibre boards (MDF) are prepared by using the thermo-mechanical technique. Thermo-mechanical pulps (TMP) are mostly bonded with acid curing urea formaldehyde resins (UF-resins) and melamine modified urea formaldehyde resins (MUF-resins). During thermo-mechanical pulping wood is degraded by hydro-thermal treatment leading to formation of different chemical compounds. Evidence has been adduced that degradation products have a negative bearing on the bondability of the fibres with binders such as alkaline curing phenol formaldehyde resins (PF-resins) or polymers based on 4,4´-diphenylmethandiisocyanat (PMDI) for making moisture resistant bonded boards.
Results of research work carried out by the University of Göttingen, the Fraunhofer-Institute of Wood Research (WKI) in Braunschweig and the Institute of Wood Technology Dresden (IHD) have proved that chemo-thermo-mechanical pulps (CTMP) are superior to TMP on bonding with moisture resistant binders including PF-resins and PMDI binders. MDF made from CTMP pulps are of higher mechanical strength and superior hydrolysis resistance compared to boards from TMP.
The paper explains the difference in behaviour of TMP and CTMP towards bonding and elucidate in depth the possibilities of using the chemo-thermo-mechanical pulping method for making moisture resistant bonded MDF.