Wood-based panels giant Egger and University of G\u00f6ttingen jointly developed so-called unoriented-strand boards (USB) made of soft hardwoods such as silver birch, alder, poplar and willow. The project, which was funded by the German ministry of food and agriculture (BMEL), is to help making better material use of the fairly large, untapped German resources of soft hardwoods.<\/p>\n
According to a press release issued by Fachagentur Nachwachsende Rohstoffe (FNR), a government agency charged with the implementation of the project, the results were very positive. The mechanical and technical properties of soft hardwood USB would range somewhere between regular OSB and particleboard.<\/p>\n
As a part of the project, the partners produced both pure soft-hardwood USB and USB made of a mix of soft hardwoods and pine as well as pure pine USB. Both USB types containing hardwoods performed at least as well or even better than the pure pine USB, according to FNR. Volatile organic compound (VOC) emissions, in particular, were lower in soft-hardwood USB and in mixed products.<\/p>\n
In USB, wooden particles and strands are not \u201coriented\u201d, like in normal OSB, but scattered randomly. The board can be produced on normal particleboard production lines.<\/p>\n
Soft hardwoods account for roughly 10% of German forestlands and they are being made little material use of so far, according to FNR. However, the supply of soft hardwoods is not large enough to allow for a full replacement of softwoods in OSB \u2013 or USB \u2013 production, which is why a mix of both types of wood was tested as well.<\/p>\n
Among the soft hardwoods tested, alder showed the best performance-mix with the lowest VOC and formaldehyde emissions. The bending strength of alder USB is comparable to that of pine OSB\/3 and the swelling rate was lower than in pine boards. Willow performed second best on average, with an even higher bending strength than alder. Birch and poplar USB also performed similarly or better than pine USB in most parameters.<\/p>\n