Effect of Boric Acid Addition into Urea Formaldehyde Adhesive on Properties of Rubberwood Plywood

Abstract

In this study, the effect of boric acid addition (5%, 10% and 15% w/w of solid content of resin) into urea formaldehyde resin (UF) on resin properties was evaluated. Shear strength, formaldehyde emission content, white rot (Trametes versicolor) and brown rot (Gloeophyllum striatum) resistance and subterranean termite (Coptotermes gestroi) resistance of rubberwood plywood which was produced with UF resin added boric acid in certain amount were also investigated. It revealed that the addition of boric acid into UF resin help decrease pH of resin to acid condition. It caused the decreasing gel time and increasing solid content of UF resin. Formaldehyde emission content of rubberwood plywood produced with UF resin added boric acid was decreased. Boric acid addition into UF resin enhanced white rot and brown rot resistance. Subterranean termite resistance of rubberwood plywood produced with UF resin added boric acid was improved. However, boric acid addition into UF resin did not negatively affected on shear strength of rubberwood plywood.