The Performance of UF Adhesive

Performance of urea-formaldehyde (UF) resin can be improved by modified low molar ratio UF resins were developed to improve water resistance properties and reduce the formaldehyde emission of its bonded products. Usually by control of process reaction pressure. The effects of modifier feeding amount can be test by Fourier transform infrared spectroscopy measurement. The viscosity, pH value, solid content, free formaldehyde content, pot time, and curing time of the UF resins were also tested according to National Standards methods. The results show that the modified 1.00 molar ratio Urea Formaldehyde (UF) resins show lower free formaldehyde content and higher boiling-water-resistance comparing with unmodified ones. The boiling-water-resistant bonding strength of poplar plywood bonded with modified UF resin at 140 degrees C hot-press temperature can reach type I grade (100 degrees C water bath 3h) plywood requirement and the formaldehyde emission can meet the E0 grade plywood need.

Formaldehyde-to-urea mole ratio (F/U) affects formaldehyde emission from particleboard and plywood bonded with urea-formaldehyde (UF) adhesives, and how this ratio affects certain other adhesive and board properties. It is difficult to measure the dependence of various properties on the mole ratio or determine lower limits of the mole ratio for a particular property because of the range in resin, board, and testing parameters used in the cited studies. However, the available data at least suggest some limitations on F/U to UF resin and the affected to particleboard systems for the maintenance of acceptable properties.