CURING BEHAVIOR OF WOOD ADHESIVES UNDER HIGH-PRESSURE STEAM .1.

The curing behavior of aqueous phenol formaldehyde (PF) resol resin un der steam-injection heating was investigated using several analytical methods. The results were as follows: (1) The curing reaction of 2-hyd roxybenzyl alcohol as a model compound, under steam-injection at 160 d egrees C was followed by rapid formation and then breakdown of the eth er group. (2) By steam-injection at the higher temperature of 160 degr ees C, it was revealed that the PF resin immediately cured to some deg ree in a few minutes; after that, it did not reach a full cure. The re sin also accompanied the rapid disappearance of the ether structure. I n the resin heated by steam-injection, free water hindered the curing reaction, and by-products were contained. At the lower temperature of 120 degrees C, the curing reaction of the resin was somewhat delayed c ompared to that heated under conventional hot-platen heating.