Evaluation of Melamine-Modified Urea-Formaldehyde Resin for Plywood Flooring Adhesive Application

A melamine-modified urea-formaldehyde (MUF) resin, as a plywood flooring adhesive, was synthesized in the laboratory with a formaldehyde/(urea + melamine) mole ratio of 1.48. The physical characteristics of the MUF resin including nonvolatile solids, specific gravity, pH, free formaldehyde, and viscosity, etc., were determined. The MUF resin was mixed with an extender, pinenut flour and NH4Cl. The mixture contained approximately 39 percent resin solids, 55.8 percent total solids, and 44.2 percent water. The mixture gel time with the catalyst was 1.9 minutes at 100 degrees C. Laboratory plywood panels with the MUF resin adhesive mixture were made using Korean wood species. The plywood panels were tested for tension shear strength after 3-hour soak (60 degrees C water) aging method, modulus of rupture, formaldehyde emission, and surface abrasion according to the procedures of KS F 3101, and KS F 3114. The test results showed that the MUF resin can be used for Ondol plywood flooring production.