STEAM INJECTION PRESSING

A process developed at the U.S. Forest Products Laboratory injects saturated steam into a flakeboard mat during press closure to reduce the time needed to bring the centerline of the flakeboard to resin curing temperatures. Total press time for a ½ in. (13 mm), 40 lb/ft 3 (641 kg/m 3 ), phenolic-bonded flakeboard has been reduced by 60%, without degrading internal bond or flexure properties. Control over plasticization of the mat reduces press closing pressures and provides a means to significantly alter the vertical density profile.