A multi-stage cascade use of wood composite boards

A multi-stage cascade model was implemented on wood composite boards in four stages: particle boards → 100% recycling → middle density fibreboards → 100% recycling → paper liner. Preparation of composite boards bonded with urea-formaldehyde resin was simulated on plates 400 x 400 mm and final fiber was pulped using semi-production refiners to create the conditions closed to real. Mass changes and losses were observed during a whole simulated life process.
Results confirmed a deterioration of mechanical strength of recycled particle boards, the flexural strength in 13% and internal bond strength in 34% and slight increasing of the modulus of elasticity in static bending in 1.3%. Termomechanical pulping for the fineness in range 13°SR-24°SR (Schopper-Riegler) was chosen as appropriate for a fibrous board preparation from recycled chips, but their mechanical properties are at lowest levels compared to the requirements of standards. A low quality paper liner containing OCC, to improve its strength, was produced in the last stage of cascading.