Properties and decay resistance of preservative-treated Douglas-fir flakeboard

The effect of pretreatment of Douglas-fir flakes with CCA-C, borate, and azaconazole on properties of flakeboard was studied. Flakes had higher retention levels of CCA-C and borate in their ends than in their centers. The distribution of chemicals was uniform in panels, which indicates that the chemicals did not migrate during hot-pressing. Treatment markedly enhanced resistance to brown rot (Postia placenta). Borate-treated panels had large thickness swelling and often delaminated when exposed to hot, wet conditions. In static bending and internal bond tests, strength reduction for borate- and CCAC-treated panels was evident. Azaconazole showed no deleterious effect on strength