Application of cure-accelerated phenol-formaldehyde (PF) adhesives for three-layer medium density fiberboard (MDF) manufacture

This study was conducted to optimize hot pressing time and adhesive content for the manufacture of three-layer medium density fiberboard (MDF) through the cure acceleration of phenol-formaldehyde (PF) adhesives by adding thre e carbonates (propylene carbonate, sodium carbonate, and potassium carbonat e) in the core layer. Carbonate type, carbonate level, PF resin content, an d hot pressing time were evaluated on the basis of the performance of MDF p anels prepared. The application of cure-accelerated PF adhesives by the add ition of propylene carbonate reduced both PF resin content and total hot pr essing time by 38% and 29%, respectively, for the manufacture of quality th ree-layer MDF panels (19.1 mm thickness) under the hot-pressing temperature of 205 degreesC. The optimum concentration of propylene carbonate for cure acceleration of PF resin was found to be 3 wt% by weight based on the resi n solids. Bending properties, on one hand, were independent of carbonate ty pe and level, and complied with the minimum requirements by ANSI. Internal bond (IB) strength, on the other hand, was closely related with carbonate t ypes and level used.