Thermo-hydrolytic recycling of urea-formaldehyde resin-bonded laminated particleboards

Abstract

The large global production of particleboards creates an equal quantity of particleboard waste after completion of their service life. Given increasing demand for green products and government environmental policies, it is urgent to develop technologies to recycle these used composite panels into valuable raw materials. This study was conducted to recover particles from waste laminated particleboards using various thermo-hydrolytic treatments. The recovered particles were used as raw materials with different substitutions of fresh particles to manufacture particleboard panels. The performance of the resulting particleboards was evaluated in terms of their mechanical properties and formaldehyde emissions. The nitrogen content of the control and resulting particles were measured to determine the resin removal in recycled particles. The results suggested that different thermo-hydrolytic treatments did not have significant influence on particles size distribution. Approximately 65% of urea-formaldehyde resin was removed from the particleboards treated at 140 °C/20 min. Particles recycled at 140 °C/20 min were comparable to fresh particles in terms of mechanical properties and formaldehyde emissions, and 100% of the recycled particles were used in the manufacture of particleboard without an adverse impact on the board performance.