Characterisation of solvent components in light organic solvent preservative (LOSP) treated pine sapwood boards

Light organic solvent preservative (LOSP) treatment of radiata pine (Pinus radiata D. Don) is an important component of the wood processing industry in New Zealand in the production of mouldings, plywood, fascia and weatherboards.Advantages of LOSP include the ability to treat product in final form and the absence of problems associated with other treatment methods, such as swelling, the need for further drying and disposal of treated wood waste. - The LOSP treatment used in this study was based on the Double Vacuum Process. The New Zealand Hazard Class H3 for LOSP treatment requires complete penetration of sapwood with preservative for timber up to 50 mm thick. For tin-based preservatives the minimum retention level is set at 0.08 % Sn (m/m). - Satisfactory penetration and retention of preservative are usually achived when solution uptake is between 30 and 40 L/cbm, but this level is often exceeded, particularly with sapwood (Dawson et. al. 1998). Excessive solvent retention can cause unsatisfactory paint curing and adhesion, resin bleeding, blistering, gloss loss and paint incompatibility.