Isocyanat-Verleimung von Spanplatten unter Berücksichtigung spezieller Holzargen

In laboratory particleboards whose surface and core layers were bonded with phenolic formaldehyde resin and isocyanate respectively, a certain influence can be noted of the use of specific wood species for core layers that consist exclusively of chips from those wood species. Of all investigated wood species (alder, poplar, spruce, pine, birch, beech and oak) alder showed maximum values with regard to dry and wet internal bond whereas minimum values were recorded for beech and oak. The very low wet internal bond values for beech and oak were particularly remarkable. Wool particles were produced from cut poplar particles in the laboratory and used for the core layer. The other wood species were mixed with these poplar wool particles and with cut pine particles at a ratio of 50:50. In most wood species the addition of poplar wool particles produced better wet internal strength values than were achieved with unmixed core layers. Poplar wool particles improve wet internal bond properties of beech and oak particleboards to a far greater extent than do cut pine particles.