Korean filler raw materials for plywood adhesives

Korean-source residues from walnut, pinenut, and ginkgonut shells were eval uated as fillers in adhesives for bonding plywood made from New Zealand rad iata pine veneer. The nutshell residues were prepared by drying to a 6 to 8 percent moisture content and by grinding the dry material in a laboratory Wiley mill to a 75-mu m (200-mesh) screen size. The nutshell residue filler s were compared to a furfural-process residue filler (control) commonly use d in adhesives of the United States for bonding structural plywood and lami nated veneer lumber. Plywoods were uniformly assembled (around 30 min, asse mbly time) and cured at two hot press times (4 and 5 min.) for each filler type and tested for physical properties per the U.S. Product Standard PS 1- 95. All plywood made with the adhesives containing the Korean nutshell resi due fillers were comparable in shear strength and wood failure quality to t he control-bonded plywood. The results indicated that the Korean nutshell r esidues would be suitable as fillers for structural plywood adhesives.