Development of a cornstarch adhesive for laminated veneer lumber bonding for use in engineered wood flooring

To produce aldehyde-free engineered wood flooring, we developed a cornstarch-based adhesive for laminated veneer lumber bonding. Polyvinyl alcohol was used as the tackifier, wheat flour as the filler, and polyisocyanate prepolymer as the reinforcing agent. After the application of the cornstarch adhesive to the engineered wood flooring, we found that the cornstarch adhesive had excellent adhesion in the laminated wood parquet. The properties of the cornstarch-based adhesive met the requirements of GB/T 14074-2006, GB/T 20241-2006, and GB/T 18103-2006 for non-structure interior adhesives. When lumber veneer (thickness, <= 2.2 mm) was used, the engineered wood flooring showed good dimensional stability after 1-2 min of hot-pressing pretreatment (temperature, 100-120 degrees C; pressure, 0.83 MPa). The main physical and chemical properties also met the requirements of GB/T18103-2000, Engineered Wood Flooring. The emission of formaldehyde during production was <= 0.05 mg/l, lower than the GB/T18103-2000 requirement of <= 0.124 mg/l. The results of this study provide practical and forward-looking guidelines for expanding the application of biomass-based adhesives in the manufacture of laminated veneer lumber.