Press-induced lateral resin flow and its effects on resin area coverage on composite wood strands

Abstract

Resin flow during hot pressing affects resin area coverage on the wood surface and penetration into the wood substrate, and further affects the bonding performance of wood composite products. This study explored the flowing characteristics of a phenolic resin on a wood strand surface and its effects on resin area coverage under various conditions. The results indicated that the heat and pressure of hot pressing made the resin flow and significantly increased the resin area coverage. Three factors, i.e., compaction ratio of wood strands, pressing temperature, size and thickness of resin spots, had effects on resin flow and resin area coverage. The resin area coverage after hot pressing increased with compaction ratio and reached the optimum value of compaction ratios ranging from 1.25 to 1.30. The pressing temperature, however, gave very similar effects on resin flow and resin area coverage when the pressing temperature was far above the temperature at which the resin begins to flow. The small resin spots generally showed a higher increase in resin area coverage than the big spots. However, this effect was somehow masked by the effect of spot thickness, which demonstrated a more significant effect on the resin flow and resin area coverage.