The bending properties of aspen waferboard can be improved by increasing the resin content and/or board density. These options, however have limited effect and are very costly. On the other hand, panels produced with longer, oriented stands have demonstrated significant improvements in bending strength and stiffness. The panel industry has recently used wafers or strands up to approximately 102mm (4in), however, the utilization of much longer material is practical. In addition to more efficient use of the wood resource, structural panels with improved properties can penetrate more demanding applications, particularly as future engineering materials, and overcome some problems experienced with traditional wood composites such as creep. The overall objective of the study was to demonstrate that by using long strands, coupled with appropriate strand alignment, strand thickness, and face-to-core layer ratio, a structural panel can be produced with superior strength and stiffness in the aligned direction while maintaining adequate properties in the cross direction. The specific objective for this year's work was to establish the improved performance using panels produced in structural sizes and under conditions that parallel those of the industry more closely. Manufacturers of oriented strandboard and waferboard can use the information to produce high performance OSB panel products with minimal effects on production parameters and costs.
This study was undertaken in response to the many troubleshooting enquiries received from manufacturers and users of overlaid panel products as demand for and production of these products increase. In the past, Canada was without an independent laboratory for conducting overlay tests in accordance with Canadian and United States standards. During the past three years, Forintek staff have acquired the expertise and the testing equipment needed to effectively evaluate overlays in accordance with standard test procedures. Information on the various types of decorative overlays and coatings used to finish wood-based panels was summarized in terms of properties, adhesives used, and typical applications. A computer and a hard copy file database was developed from information gathered from the literature, from visits to mills and other facilities, and from discussions with industry representatives and other colleagues. A dedicated Overlay Testing Laboratory was established at Forintek with all the necessary test equipment and with displays of the reference standards and overlay and edgebanding materials. Three particleboard manufacturers provided Forintek with samples overlaid with melamine-impregnated paper for evaluation in accordance with standard test procedures. Two common problems with which Forintek has been successful in providing guidance to the industry are described.
Virtually all mills located in Canada have at least considered, or implemented scanning technology. Scanning not only enables mills to ensure that closer to optimum recovery and productivity is obtained, but it also avails the opportunity to manage more efficiently operations and provide a basis for quality and operations control.
Previous research at Forintek Canada Corp. showed that by optimizing aspen strand alignment, strand length, strand thickness, and face-to-core (f/c) layer composition, three layer oriented strandboard (OSB) panels can be produced with bending properties significantly exceeding those of CSP commercial plywood. Also, the creep behaviour under room conditions was comparable for the two panel types. The specific objective for this year's work was to extablish the improved performance using panels produced in structural sizes and under conditions that parallel those of the industry more closely.
The ultimate objectives over the three-year period of the study are to establish a centre of expertise, a testing facility, and a quality assurance program at Forintek Canada Corp. for the overlay panel industry.