MODIFIED LIGNOSULFONATE AS ADHESIVE

Oxidized lignosulfonate (LS-OB) displays a high crosslinking during thermal condensation. When LS-OB was used as a partial substitute of urea-formaldehyde (UF) in wood adhesive, a positive effect on the curing of resin could be observed. With 30-40% substitution, no detriment in strength properties of particleboard was observed. Polycondensation of lignin and UF could occur between methylol groups in UF resin and hydroxyl and carbonyl groups in lignin, through ether bonds and methylene bridges. A high surface activity of LS-OB would reduce the surface tension of binder solution and facilitate its distribution on wood particles, improving consequently the strength properties of particleboard. (C) 1994 John Wiley & Sons, Inc.