Study on Optimization Technology of Plywood by Using Powder Larch Tannin PF Adhesive

The preparation of powder larch (Larix) tannin phenol formaldehyde (TPF)adhesive and technology of hot pressing of plywood were studied. The results demonstrated that the ideal mixing ratio of powder TPF and water was 10∶9 by weight and the bonding strength was improved after laying the blended liquid adhesive for 24 h. Adding flour by 5 % or 5 % of flour together with 5 % of wood powder can strengthen the bonding strength of plywood. The optimum parameters of Masson's Pine ( Pinus massoniana ) plywood manufacturing technology by using TPF adhesive were as following: moisture content of veneer 7%~8%, resin consumption 275 g/m 2 for double sides, veneers assembly time about 1 h, hot pressing temperature as 140 ℃, hot pressing time as 0.9 min/mm of thickness for general plywood and hot pressing pressure as 1.0~1.2 MPa.