Soya based phenolic resin for plywood manufacture

Phenolic and amino resins have been the preferred adhesives for the production of weather and moisture resistant wood-based panel products. Environmental concerns and the higher cost of petroleum based resins have resulted in the development of technologies to replace phenol by bio-materials for panel production. Natural bio-materials such as Cardanol (CNSL), tannin, lignin etc., have been tried as substitutes for phenol in the development of PF for panel products at IPIRTI. Hence a study was initiated to develop phenol-soya formaldehyde adhesive for the manufacture of exterior grade plywood. In this study the condition for denaturing soya flour were optimized to maximize its incorporation into the final polymerized structure. Soya flour was made to react with phenol and formalin in presence of caustic to make durable adhesives. About 40 % substitution of phenol by soya was optimized for making exterior grade plywood having strength properties confirming to relevant specifications (IS: 848-2006 and IS: 303-1989). The adhesive developed on laboratory scale meets the requirement of IS 848: 2006 (Anon 2006) for boiling water proof grade plywood. The panels were evaluated for mechanical properties as per IS: 303:1989 (Anon 1989) and the results conforms to the requirement of relevant specifications.