SURFACE INACTIVATION IN VENEER DRYING PROCESS AND ITS EFFECTS ON BONDING STRENGTH

Veneer drying process is an important stage in the production of wood based composites such as plywood and LVL panels. Because veneer drying becomes a bottleneck in the production process due to the inefficient equipment and methods. Although drying temperatures between 90-160°C may be considered normal, increased temperatures are being used to reduce the overall drying time and increase capacity. However, the reduction in drying time often results in an increase in drying related defects such as checks, splits and warp and decrease in wettability. Surface inactivation is one of these defects which occur on wood surfaces with heat effect and results in the loss of bonding ability. Surface inactivation is defined as physical and chemical modifications on the wood surfaces that results in reduced ability of the adhesive to properly wet, flow, penetrate and cure. Many investigations have been conducted to improve adhesion of inactivated wood surfaces, but no comprehensive solution has been revealed so far