Low-cost natural binder for particleboards production: study of manufacture conditions and stability

Nowadays, the majority of adhesives used in particleboards (PB) manufacture are formaldehyde-based. In the present research work a low-cost bioadhesive, based on the combination of thick spent sulfite liquor (TSSL) with wheat flour, was tested for the production of three-layer particleboards, at different conditions (particleboards target density, pressing time, pressing temperature, wood type and binder age). It was possible to produce particleboards with densities ranging from 682 kg m(-3) to 783 kg m(-3), at pressing temperatures from 180 to 210 degrees C, and pressing times between 8 and 10 min. All the particleboards produced in these conditions were in accordance with the internal bond strength requirements of standard EN 312 for particleboards type P2 (0.35 N mm(-2)). The best result (0.69 +/- 0.01) N mm(-2) was obtained for particleboards pressed for 10 minutes at 200 degrees C with the recycled wood mix. Regarding resin stability, the particleboards manufactured with the binder, stored for 30 days, presented good internal bond strength ((0.58 +/- 0.02) N mm(-2)), above the requirements of standard EN 312 for particleboards type P2