Synthesis of Wood Lignin-Urea-Formaldehyde Resin Adhesive

Abstract

Lignin-urea-formaldehyde resin adhesive was synthesized with alkali lignin from gramineae waste pulping liquor. Alkali lignin was purified and hydroxymethylated with HCHO and then crosslinked with urea-formaldehyde resin, polyvinyl alcohol and melamine. Results showed that lignin content in purified alkali lignin was 86.91%, both binding strength and free HCHO content of urea-formaldehyde resin synthesized from hydroxymethylated lignin reached the optimum value. The proper lignin amount for preparing resin was 30%, and the binding strength at this condition was 4.56MPa, and free formaldehyde content was 0.049%.